1
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Kim D, Elf P, Nilsson F, Hedenqvist MS, Larsson A. In-Depth Understanding of the Effect of the Distribution of Substituents on the Morphology and Physical Properties of Ethylcellulose: Molecular Dynamics Simulations Insights. Biomacromolecules 2024; 25:4046-4062. [PMID: 38913613 PMCID: PMC11238332 DOI: 10.1021/acs.biomac.4c00166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/26/2024]
Abstract
Ethylcellulose (EC) is a crucial cellulose derivative with widespread applications, particularly in the pharmaceutical industry, where precise property adjustments through chemical modification are imperative. The degree of substitution (DS) and the localization of substituents along the cellulose chains are pivotal factors in this process. However, the impact of the substituent location within the repeating unit of EC remains unexplored. To address this gap, we conducted molecular dynamics simulations on amorphous EC, comparing randomly and uniformly substituted ethyl groups in the repeating units. This comprehensive study of pairwise interactions revealed significant differences in intramolecular and intermolecular hydrogen-bonding capabilities, depending on whether the hydroxyl groups were substituted at C2, C3, or C6. While our simulations demonstrated that substituent localization in the repeating unit influenced the density, number of hydrogen bonds, and conformations, the DS emerged as the dominant determinant. This insight led us to propose and validate a hypothesis: a straightforward linear function using the properties of uniform models and molar fractions can predict the properties of randomly substituted EC with a given DS. This innovative approach is anticipated to contribute to the selection of cellulose derivatives with desirable properties for the pharmaceutical industry and new applications in other fields.
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Affiliation(s)
- Donghyun Kim
- Applied
Chemistry, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
- FibRe
Centre for Lignocellulose-based Thermoplastics, Department of Chemistry
and Chemical Engineering, Chalmers University
of Technology, SE-412 96 Gothenburg, Sweden
- Wallenberg
Wood Science Center, Chalmers University
of Technology, SE-412 96 Gothenburg, Sweden
| | - Patric Elf
- Department
of Fibre and Polymer Technology, School of Engineering Sciences in
Chemistry, Biotechnology and Health, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
- FibRe
Vinnova competence center, KTH Royal Institute
of Technology, SE-100 44 Stockholm, Sweden
| | - Fritjof Nilsson
- Department
of Fibre and Polymer Technology, School of Engineering Sciences in
Chemistry, Biotechnology and Health, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
- FibRe
Vinnova competence center, KTH Royal Institute
of Technology, SE-100 44 Stockholm, Sweden
- FSCN
research centre, Mid Sweden University, 85170 Sundsvall, Sweden
| | - Mikael S. Hedenqvist
- Department
of Fibre and Polymer Technology, School of Engineering Sciences in
Chemistry, Biotechnology and Health, KTH
Royal Institute of Technology, SE-100 44 Stockholm, Sweden
- FibRe
Vinnova competence center, KTH Royal Institute
of Technology, SE-100 44 Stockholm, Sweden
- Wallenberg
Wood Science Center, KTH Royal Institute
of Technology, SE-100 44 Stockholm, Sweden
| | - Anette Larsson
- Applied
Chemistry, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
- FibRe
Centre for Lignocellulose-based Thermoplastics, Department of Chemistry
and Chemical Engineering, Chalmers University
of Technology, SE-412 96 Gothenburg, Sweden
- Wallenberg
Wood Science Center, Chalmers University
of Technology, SE-412 96 Gothenburg, Sweden
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2
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Simon J, Schlapp-Hackl I, Sapkota J, Ristolainen M, Rosenau T, Potthast A. Towards Tailored Dialdehyde Cellulose Derivatives: A Strategy for Tuning the Glass Transition Temperature. CHEMSUSCHEM 2024; 17:e202300791. [PMID: 37923704 DOI: 10.1002/cssc.202300791] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 11/03/2023] [Accepted: 11/03/2023] [Indexed: 11/07/2023]
Abstract
The derivatization of dialdehyde cellulose (DAC) has received increasing attention in the development of sustainable thermoplastics. In this study, a series of dialcohol celluloses were generated by borohydride reduction, which exhibited glass transition temperature (Tg ) values ranging from 23 to 109 °C, depending on the initial degree of oxidation (DO) of the DAC intermediate. However, the DAC derivatives did not exhibit thermoplastic behavior when the DO of the modified DAC was below 26 %. The influence of introduced side chains was highlighted by comparing DAC-based thermoplastic materials obtained by either oximation or borohydride reduction. Our results provide insights into the generation of DAC-based thermoplastics and highlight a strategy for tailoring the Tg by adjusting the DO during the periodate oxidation step and selecting appropriate substituents in subsequent modifications.
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Affiliation(s)
- Jonas Simon
- Department of Chemistry, Institute of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences Vienna (BOKU), Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria
| | - Inge Schlapp-Hackl
- Department of Bioproducts and Biosystems, Aalto University, FI-00076, Aalto, Finland
| | - Janak Sapkota
- NE Research Center, UPM Pulp Research and Innovations, 53200, Lappeenranta, Finland
| | - Matti Ristolainen
- NE Research Center, UPM Pulp Research and Innovations, 53200, Lappeenranta, Finland
| | - Thomas Rosenau
- Department of Chemistry, Institute of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences Vienna (BOKU), Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria
| | - Antje Potthast
- Department of Chemistry, Institute of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences Vienna (BOKU), Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria
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3
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Chiriac AP, Ghilan A, Croitoriu A, Serban A, Bercea M, Stoleru E, Nita LE, Doroftei F, Stoica I, Bargan A, Rusu AG, Chiriac VM. Study on cellulose nanofibrils/copolymacrolactone based nano-composites with hydrophobic behaviour, self-healing ability and antioxidant activity. Int J Biol Macromol 2024; 262:130034. [PMID: 38340942 DOI: 10.1016/j.ijbiomac.2024.130034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 01/29/2024] [Accepted: 02/05/2024] [Indexed: 02/12/2024]
Abstract
The multiple uses of cellulose nanofibrils (CNFs) originate from their availability from renewable resources, and are due to their physico-chemical properties, biodegradability and biocompatibility. At the same time, reducing sensitivity to humidity, increasing interfacial adhesion and hydrophobic modification of the CNF surface to diversify applications and improve operation, are current targets pursued. This study focuses on the preparation of a novel gel structure using cellulose nanofibrils (CNFs) and poly(ethylene brassylate-co-squaric acid) (PEBSA50/50), a bio-based copolymacrolactone. The primary goal is to achieve the gel with reduced sensitivity to humidity and enhanced hydrophobic behaviour. The new system was characterized in comparison to its constituent components using various techniques, such as Fourier transform infrared spectroscopy, thermal analysis, X-ray diffraction, and NIR - chemical imaging. Rheological tests demonstrated the formation of the CNF_PEBSA50/50 gel as a result of physical interactions between the two polymeric partners and revealed self-healing abilities for the prepared gels. Determination of the contact angle, surface free energy, as well as dynamic measurements of the vapour sorption of the CNF_PEBSA50/50 system, confirmed the achievement of the study's aim. Furthermore, the CNF_PEBSA50/50 network was utilized to encapsulate citric acid, resulting in the creation of a new bioactive composite with both antioxidant and antimicrobial activity.
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Affiliation(s)
- Aurica P Chiriac
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania.
| | - Alina Ghilan
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Alexandra Croitoriu
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Alexandru Serban
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Maria Bercea
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Elena Stoleru
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Loredana Elena Nita
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Florica Doroftei
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Iuliana Stoica
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Alexandra Bargan
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Alina Gabriela Rusu
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
| | - Vlad Mihai Chiriac
- Petru Poni Institute of Macromolecular Chemistry, 41 A Grigore Ghica Voda Alley, 700487 Iasi, Romania
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4
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Shi Y, Geng L, Fan P, Yuan Y, Zhao J, Zhang Y. Mechanical properties and physicochemical characteristics of cotton fibers during combing process. Int J Biol Macromol 2024; 261:129791. [PMID: 38325253 DOI: 10.1016/j.ijbiomac.2024.129791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/17/2024] [Accepted: 01/25/2024] [Indexed: 02/09/2024]
Abstract
This study employs a combination of experiments and molecular dynamics to analyze the mechanical properties and surface damage characteristics of cotton fibers during the combing process. Additionally, it investigates the alterations in physical and chemical properties at the atomic scale resulting from mechanical damage. Raw cotton (RC) is combed to 1st combed cotton (1st CC), 2nd combed cotton (2nd CC) and 3rd combed cotton (3rd CC). It was found that the mechanical properties and crystallinity showed an increasing and then decreasing trend with the process of combing, and the degree of surface tearing increased, and the binding energy of C and O shifted to a lower position. The breaking strength of cotton fibers first increased by 7.4 % and then decreased by 11 % and 7.7 % respectively, and the crystallinity was CrI (RC) = 70.8 %, CrI (1st CC) = 75.3 %, CrI (2nd CC) = 72.7 %, and CrI (3rd CC) = 71.8 % respectively. The C-O bond and the C-C bond at the amorphous regions are broken after combing lead to the cellulose chain to break, resulting in a decrease in the breaking strength of the fibers. The C-O bond as well as the C-O-C bond angles changes significantly during stretching, and the increase in ordering of the amorphous regions causes an increase in crystallinity.
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Affiliation(s)
- Yuhua Shi
- Collage of Mechanical and Electrical Engineering, Tarim University, Alar, Xinjiang 843300, China; Modern Agricultural Engineering Key Laboratory at Universities of Education Department of Xinjiang Uygur Autonomous Region, Alar, Xinjiang 843300, China
| | - Liuyuan Geng
- Collage of Mechanical and Electrical Engineering, Tarim University, Alar, Xinjiang 843300, China; Modern Agricultural Engineering Key Laboratory at Universities of Education Department of Xinjiang Uygur Autonomous Region, Alar, Xinjiang 843300, China
| | - Pengwei Fan
- Collage of Mechanical and Electrical Engineering, Tarim University, Alar, Xinjiang 843300, China; Modern Agricultural Engineering Key Laboratory at Universities of Education Department of Xinjiang Uygur Autonomous Region, Alar, Xinjiang 843300, China
| | - Yang Yuan
- Collage of Mechanical and Electrical Engineering, Tarim University, Alar, Xinjiang 843300, China; Modern Agricultural Engineering Key Laboratory at Universities of Education Department of Xinjiang Uygur Autonomous Region, Alar, Xinjiang 843300, China
| | - Jun Zhao
- Collage of Mechanical and Electrical Engineering, Tarim University, Alar, Xinjiang 843300, China; Modern Agricultural Engineering Key Laboratory at Universities of Education Department of Xinjiang Uygur Autonomous Region, Alar, Xinjiang 843300, China
| | - Youqiang Zhang
- Collage of Mechanical and Electrical Engineering, Tarim University, Alar, Xinjiang 843300, China; Modern Agricultural Engineering Key Laboratory at Universities of Education Department of Xinjiang Uygur Autonomous Region, Alar, Xinjiang 843300, China.
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5
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Zhao H, Zhan J, Yun H, Mu H, Zhang D, An L, Yao H, Zhang G. Deciphering the intricate dielectric relaxation processes of cellulose paper: Extraction of distribution of relaxation time and analysis of degradation characteristics. Carbohydr Polym 2024; 324:121497. [PMID: 37985048 DOI: 10.1016/j.carbpol.2023.121497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 11/22/2023]
Abstract
Cellulose material is a dielectric with intricate microscopic relaxation processes due to its complex structure. However, conventional models and curve fitting methods used for tracing and analyzing these processes often fail to capture crucial dielectric information. This paper aimed to extract the Distribution of Relaxation Time (DRT), the most fundamental and effective dielectric information providing the time scale and relative contribution of all microscopic relaxation processes. First, a distributed extended Debye model with infinite branches was constructed based on the microscopic nature of dielectric relaxation. Then, an implicit equation of the DRT function was established, inspired by the mathematical principles of infinite subdivision and summation. To obtain the numeral solution of the DRT function, a regularization method was proposed and validated. Finally, the approach was applied to cellulose insulating paper with varying degradation degrees. The relaxation process with a long time constant played a significant role, and variations during the degradation process were attributed to reduced activation energy. With clear physical interpretation and robust mathematical foundation, our method sheds light on the intricate dielectric relaxation processes in cellulose. This not only enhances the theoretical understanding and practical application of cellulose materials but also provides valuable insights for the analysis and application of other materials.
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Affiliation(s)
- Haoxiang Zhao
- State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, China; Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, the Netherlands.
| | - Jiangyang Zhan
- State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, China.
| | - Hao Yun
- China Nuclear Power Operation Technology Corporation., Ltd, Wuhan, China.
| | - Haibao Mu
- State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, China.
| | - Daning Zhang
- State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, China.
| | - Lixuan An
- Department of Data Analysis and Mathematical Modelling, Ghent University, Ghent, Belgium.
| | - Huanmin Yao
- State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Guanjun Zhang
- State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, China.
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6
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Sun S, Wang Q, Wang X, Wu C, Zhang X, Bai J, Sun B. Dry torrefaction and continuous thermochemical conversion for upgrading agroforestry waste into eco-friendly energy carriers: Current progress and future prospect. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167061. [PMID: 37714342 DOI: 10.1016/j.scitotenv.2023.167061] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/11/2023] [Accepted: 09/11/2023] [Indexed: 09/17/2023]
Abstract
Agroforestry Waste (AW) is seen as a carbon neutral resource. However, the poor quality of AW reduced its potential application value. Even more unfortunately, chlorine in AW led to the formation of organic pollutants such as dioxins under higher temperatures. Alkali and alkaline earth metals (AAEMs) in ash may deepen the reaction degree. Co-pretreatment of dry torrefaction and de-ashing followed by thermochemical conversion is a promising technology, which can improve raw material quality, inhibit the release of organic pollutants and transform AW into eco-friendly energy carriers. In order to better understand the process, theoretical basis such as the structural characteristics, thermal properties and separation methods of structural components of AW are described in detail. In addition, dry torrefaction related reactors, process parameters, kinetic analysis models as well as the evaluation methods of torrefaction degree and environmental impact are systematically reviewed. The problem of ash accumulation caused by dry torrefaction can be well solved by de-ashing pretreatment. This paper provides a comprehensive discussion on the role of the two- and three-stage conversion technologies around dry torrefacion, de-ashing pretreatment and thermochemical conversion in products quality enhancement. Finally, the existing technical challenges, including suppression of gaseous pollutant release, harmless treatment and reuse of torrefaction liquid product (TPL) and reduction of torrefaction operating costs, are summarized and evaluated. The future research directions, such as vitrification of the reused TPL (after de-ashing or acid catalysis) and integration of oxidative torrefaction with thermochemical conversion technologies, are proposed.
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Affiliation(s)
- Shipeng Sun
- Engineering Research Centre of Oil Shale Comprehensive Utilization, Ministry of Education, Northeast Electric Power University, Jilin City, Jilin 132012, PR China; School of Energy and Power Engineering, Northeast Electric Power University, Jilin City, Jilin 132012, PR China
| | - Qing Wang
- Engineering Research Centre of Oil Shale Comprehensive Utilization, Ministry of Education, Northeast Electric Power University, Jilin City, Jilin 132012, PR China; School of Energy and Power Engineering, Northeast Electric Power University, Jilin City, Jilin 132012, PR China.
| | - Xinmin Wang
- Engineering Research Centre of Oil Shale Comprehensive Utilization, Ministry of Education, Northeast Electric Power University, Jilin City, Jilin 132012, PR China; School of Energy and Power Engineering, Northeast Electric Power University, Jilin City, Jilin 132012, PR China
| | - Chunlei Wu
- Engineering Research Centre of Oil Shale Comprehensive Utilization, Ministry of Education, Northeast Electric Power University, Jilin City, Jilin 132012, PR China; School of Energy and Power Engineering, Northeast Electric Power University, Jilin City, Jilin 132012, PR China
| | - Xu Zhang
- Engineering Research Centre of Oil Shale Comprehensive Utilization, Ministry of Education, Northeast Electric Power University, Jilin City, Jilin 132012, PR China; School of Energy and Power Engineering, Northeast Electric Power University, Jilin City, Jilin 132012, PR China
| | - Jingru Bai
- Engineering Research Centre of Oil Shale Comprehensive Utilization, Ministry of Education, Northeast Electric Power University, Jilin City, Jilin 132012, PR China; School of Energy and Power Engineering, Northeast Electric Power University, Jilin City, Jilin 132012, PR China
| | - Baizhong Sun
- School of Energy and Power Engineering, Northeast Electric Power University, Jilin City, Jilin 132012, PR China
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7
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List R, Gonzalez-Lopez L, Ashfaq A, Zaouak A, Driscoll M, Al-Sheikhly M. On the Mechanism of the Ionizing Radiation-Induced Degradation and Recycling of Cellulose. Polymers (Basel) 2023; 15:4483. [PMID: 38231912 PMCID: PMC10708459 DOI: 10.3390/polym15234483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/13/2023] [Accepted: 10/23/2023] [Indexed: 01/19/2024] Open
Abstract
The use of ionizing radiation offers a boundless range of applications for polymer scientists, from inducing crosslinking and/or degradation to grafting a wide variety of monomers onto polymeric chains. This review in particular aims to introduce the field of ionizing radiation as it relates to the degradation and recycling of cellulose and its derivatives. The review discusses the main mechanisms of the radiolytic sessions of the cellulose molecules in the presence and absence of water. During the radiolysis of cellulose, in the absence of water, the primary and secondary electrons from the electron beam, and the photoelectric, Compton effect electrons from gamma radiolysis attack the glycosidic bonds (C-O-C) on the backbone of the cellulose chains. This radiation-induced session results in the formation of alkoxyl radicals and C-centered radicals. In the presence of water, the radiolytically produced hydroxyl radicals (●OH) will abstract hydrogen atoms, leading to the formation of C-centered radicals, which undergo various reactions leading to the backbone session of the cellulose. Based on the structures of the radiolytically produced free radicals in presence and absence of water, covalent grafting of vinyl monomers on the cellulose backbone is inconceivable.
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Affiliation(s)
- Richard List
- Department of Chemical Engineering, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
- UV/EB Technology Center, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
| | - Lorelis Gonzalez-Lopez
- Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA
| | - Aiysha Ashfaq
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| | - Amira Zaouak
- Research Laboratory on Energy and Matter for Nuclear Science Development, National Center for Nuclear Science and Technology, Sidi-Thabet 2020, Tunisia;
| | - Mark Driscoll
- UV/EB Technology Center, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
| | - Mohamad Al-Sheikhly
- Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA
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8
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Mileo PGM, Krauter CM, Sanders JM, Browning AR, Halls MD. Molecular-Scale Exploration of Mechanical Properties and Interactions of Poly(lactic acid) with Cellulose and Chitin. ACS OMEGA 2023; 8:42417-42428. [PMID: 38024724 PMCID: PMC10652380 DOI: 10.1021/acsomega.3c04880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 12/01/2023]
Abstract
Poly(lactic acid) (PLA), one of the pillars of the current overarching displacement trend switching from fossil- to natural-based polymers, is often used in association with polysaccharides to increase its mechanical properties. However, the use of PLA/polysaccharide composites is greatly hampered by their poor miscibility, whose underlying nature is still vastly unexplored. This work aims to shed light on the interactions of PLA and two representative polysaccharide molecules (cellulose and chitin) and reveal structure-property relationships from a fundamental perspective using atomistic molecular dynamics. Our computational strategy was able to reproduce key experimental mechanical properties of pure and/or composite materials, reveal a decrease in immiscibility in PLA/chitin compared to PLA/cellulose associations, assert PLA-oriented polysaccharide reorientations, and explore how less effective PLA-polysaccharide hydrogen bonds are related to the poor PLA/polysaccharide miscibility. The connection between the detailed chemical interactions and the composite behavior found in this work is beneficial to the discovery of new biodegradable and natural polymer composite mixtures that can provide needed performance characteristics.
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Affiliation(s)
| | | | - Jeffrey M. Sanders
- Schrödinger,
Inc., 1540 Broadway, New York, New York10036, United States
| | - Andrea R. Browning
- Schrödinger,
Inc., 01 SW Main St #1300, Portland, Oregon 97204, United States
| | - Mathew D. Halls
- Schrödinger,
Inc., 5820 Oberlin Dr., San Diego, California 92121, United States
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9
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Daicho K, Fujisawa S, Saito T. Linear Correlation between True Density and Crystallinity of Regenerated and Mercerized Celluloses. Biomacromolecules 2023; 24:661-666. [PMID: 36583854 DOI: 10.1021/acs.biomac.2c01067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Regenerated and mercerized celluloses are widely used in our daily life and industries. Examples include clothes, medical supplies, and separation membranes. In such applications, the true density is an important derived physical quantity for refining the structural designs of regenerated and mercerized celluloses. Here, we report the true density-crystallinity correlation of regenerated and mercerized celluloses. Seven samples were prepared through either dissolution-regeneration or mercerization, and the true density of each sample was measured by helium gas pycnometry. The crystallinity was evaluated by solid-state 13C nuclear magnetic resonance spectroscopy based on the ratio of the carbon atoms in the crystallite core to those at crystallite surfaces and in the surrounding amorphous matrix. We found that the true density of regenerated and mercerized celluloses is directly proportional to crystallinity, irrespective of the preparation process. Additionally, the molecular packing density at the crystallite surfaces was found to be similar to that in the amorphous matrix.
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Affiliation(s)
- Kazuho Daicho
- Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo113-8657, Japan
| | - Shuji Fujisawa
- Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo113-8657, Japan
| | - Tsuguyuki Saito
- Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo113-8657, Japan
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10
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Cremer G, Danthine S, Van Hoed V, Dombree A, Laveaux AS, Damblon C, Karoui R, Blecker C. Variability in the substitution pattern of hydroxypropyl cellulose affects its physico-chemical properties. Heliyon 2023; 9:e13604. [PMID: 36879748 PMCID: PMC9984446 DOI: 10.1016/j.heliyon.2023.e13604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Hydroxypropyl cellulose (HPC) is a water-soluble polymer with many applications in food, pharmaceutical, medical, or paints industries. Past studies have reported that differences in functionality can occur between products of similar pharmaceutical grades. Understanding the origin of these differences is a major challenge for the industry. In this work, the structure and physico-chemical properties of several HPC samples of the same commercial grade were studied. Structural analysis by NMR and enzymatic hydrolysis were performed to study molar substitution and distribution of substituents along the polymer chain respectively. Water-polymer interactions, surface properties as well as rheological and thermal behavior were characterized to tentatively correlate them with the structure, and gain new insights into the structure-function relationship of this polymer. The differences in structure revealed between the samples affect their properties. The unexpected behavior of one sample was attributed to a more heterogeneous substitution pattern, with the coexistence of highly and weakly substituted regions along the same polymer chain. The more block-like distribution of substituents has a great effect on the clouding behavior and surface tension reduction ability of the polymer.
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Affiliation(s)
- Gilles Cremer
- Laboratory of Food Science and Formulation, GxABT, University of Liege, Belgium
| | - Sabine Danthine
- Laboratory of Food Science and Formulation, GxABT, University of Liege, Belgium
| | | | | | | | - Christian Damblon
- MolSys Research Unit, Faculty of Sciences, University of Liege, Belgium
| | - Romdhane Karoui
- Univ. Artois, Univ. Lille, Univ. Littoral Côte D'Opale, Univ. Picardie Jules Verne, Univ. of Liege, INRAE, Junia, UMR-T 1158, BioEcoAgro, F-62300, Lens, France
| | - Christophe Blecker
- Laboratory of Food Science and Formulation, GxABT, University of Liege, Belgium
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11
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Gibbon C, Di Pietro P, Storr M, Broughton D, Skylaris CK. Using molecular dynamics to simulate realistic structures of nitrocellulose of different nitration levels. Phys Chem Chem Phys 2023; 25:3190-3198. [PMID: 36622755 DOI: 10.1039/d2cp05550c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Nitrocellulose is a reactive derivative of cellulose, one of the most commonly occurring natural materials. Nitration of cellulose decreases the stability of the structure, meaning less is understood about its structure and reactions. Although cellulose is often found in fully crystalline forms, nitrocellulose is more commonly paracrystalline, or amorphous. We present a protocol based on molecular dynamics simulations for creating realistic structures of nitrocellulose, particularly focusing on the crystallinity of the systems being created. We will also provide a detailed analysis of the geometric and dynamical parameters used to quantify the degree of crystallinity for the structures created here, with nitration levels varying from 0-14.14 wt% nitrogen content. Paracrystalline cellulose was not created using the protocol designed here, although it was found that the more nitrated a nitrocellulose system, the more the structure tends to paracrystallinity. This is due to a decrease in the number of hydrogen bonds present, and an increase in the size of the functional groups pushing the chains apart and weakening the interactions between the chains of the structure. The structures created are representative of realistic systems, which in the future will be able to be used to build further understanding of long-term storage of nitrocellulose.
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Affiliation(s)
- Catriona Gibbon
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
| | | | - Mark Storr
- AWE Aldermaston, Reading, Berkshire, RG7 4PR, UK
| | | | - Chris-Kriton Skylaris
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
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12
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Simon J, Fliri L, Sapkota J, Ristolainen M, Miller SA, Hummel M, Rosenau T, Potthast A. Reductive Amination of Dialdehyde Cellulose: Access to Renewable Thermoplastics. Biomacromolecules 2023; 24:166-177. [PMID: 36542819 PMCID: PMC9832504 DOI: 10.1021/acs.biomac.2c01022] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The reductive amination of dialdehyde cellulose (DAC) with 2-picoline borane was investigated for its applicability in the generation of bioderived thermoplastics. Five primary amines, both aliphatic and aromatic, were introduced to the cellulose backbone. The influences of the side chains on the course of the reaction were examined by various analytical techniques with microcrystalline cellulose as a model compound. The obtained insights were transferred to a 39%-oxidized softwood kraft pulp to study the thermal properties of thereby generated high-molecular-weight thermoplastics. The number-average molecular weights (Mn) of the diamine celluloses, ranging from 60 to 82 kD, were investigated by gel permeation chromatography. The diamine celluloses exhibited glass transition temperatures (Tg) from 71 to 112 °C and were stable at high temperatures. Diamine cellulose generated from aniline and DAC showed the highest conversion, the highest Tg (112 °C), and a narrow molecular weight distribution (D̵ of 1.30).
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Affiliation(s)
- Jonas Simon
- Department
of Chemistry, Institute of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences
Vienna (BOKU), Konrad-Lorenz-Strasse
24, Tulln3430, Austria
| | - Lukas Fliri
- Department
of Bioproducts and Biosystems, Aalto University, Aalto0076, Finland
| | - Janak Sapkota
- NE Research
Center, UPM Pulp Research and Innovations, Lappeenranta53200, Finland
| | - Matti Ristolainen
- NE Research
Center, UPM Pulp Research and Innovations, Lappeenranta53200, Finland
| | - Stephen A. Miller
- The
George and Josephine Butler Laboratory for Polymer Research, Department
of Chemistry, University of Florida, Gainesville, Florida32611-7200, United States
| | - Michael Hummel
- Department
of Bioproducts and Biosystems, Aalto University, Aalto0076, Finland
| | - Thomas Rosenau
- Department
of Chemistry, Institute of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences
Vienna (BOKU), Konrad-Lorenz-Strasse
24, Tulln3430, Austria,
| | - Antje Potthast
- Department
of Chemistry, Institute of Chemistry of Renewable Resources, University of Natural Resources and Life Sciences
Vienna (BOKU), Konrad-Lorenz-Strasse
24, Tulln3430, Austria,
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13
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Functionalization of Conductive Polymers through Covalent Postmodification. Polymers (Basel) 2022; 15:polym15010205. [PMID: 36616554 PMCID: PMC9824246 DOI: 10.3390/polym15010205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 12/19/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023] Open
Abstract
Organic chemical reactions have been used to functionalize preformed conducting polymers (CPs). The extensive work performed on polyaniline (PANI), polypyrrole (PPy), and polythiophene (PT) is described together with the more limited work on other CPs. Two approaches have been taken for the functionalization: (i) direct reactions on the CP chains and (ii) reaction with substituted CPs bearing reactive groups (e.g., ester). Electrophilic aromatic substitution, SEAr, is directly made on the non-conductive (reduced form) of the CPs. In PANI and PPy, the N-H can be electrophilically substituted. The nitrogen nucleophile could produce nucleophilic substitutions (SN) on alkyl or acyl groups. Another direct reaction is the nucleophilic conjugate addition on the oxidized form of the polymer (PANI, PPy or PT). In the case of PT, the main functionalization method was indirect, and the linking of functional groups via attachment to reactive groups was already present in the monomer. The same is the case for most other conducting polymers, such as poly(fluorene). The target properties which are improved by the functionalization of the different polymers is also discussed.
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14
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Current Challenges and Perspectives for the Catalytic Pyrolysis of Lignocellulosic Biomass to High-Value Products. Catalysts 2022. [DOI: 10.3390/catal12121524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Lignocellulosic biomass is an excellent alternative of fossil source because it is low-cost, plentiful and environmentally friendly, and it can be transformed into biogas, bio-oil and biochar through pyrolysis; thereby, the three types of pyrolytic products can be upgraded or improved to satisfy the standard of biofuel, chemicals and energy materials for industries. The bio-oil derived from direct pyrolysis shows some disadvantages: high contents of oxygenates, water and acids, easy-aging and so forth, which restrict the large-scale application and commercialization of bio-oil. Catalytic pyrolysis favors the refinement of bio-oil through deoxygenation, cracking, decarboxylation, decarbonylation reactions and so on, which could occur on the specified reaction sites. Therefore, the catalytic pyrolysis of lignocellulosic biomass is a promising approach for the production of high quality and renewable biofuels. This review gives information about the factors which might determine the catalytic pyrolysis output, including the properties of biomass, operational parameters of catalytic pyrolysis and different types of pyrolysis equipment. Catalysts used in recent research studies aiming to explore the catalytic pyrolysis conversion of biomass to high quality bio-oil or chemicals are discussed, and the current challenges and future perspectives for biomass catalytic pyrolysis are highlighted for further comprehension.
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15
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Mechanism Analysis of Ethanol Production from Cellulosic Insulating Paper Based on Reaction Molecular Dynamics. Polymers (Basel) 2022; 14:polym14224918. [PMID: 36433045 PMCID: PMC9695054 DOI: 10.3390/polym14224918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/16/2022] Open
Abstract
The paper/oil system is the main component of transformer insulation. Indicator plays a vital role in assessing the aging condition of local hot spots of transformer insulation paper. The cellulosic insulating paper is mainly composed of cellobiose. This study uses the molecular dynamics method based on reactive force field (ReaxFF) to pyrolyze the insulating paper. Various production paths of ethanol were studied at the atomic level through ReaxFF simulations. A model consisting of 40 cellobioses was established for repeated simulation at 500 K-3000 K. Besides, to explore the relationship between the intermediate products and ethanol, the combination model of intermediate products (levoglucosan, acetaldehyde, 2,2-dihydroxyacetaldehyde) was established for repeated simulation. The simulation results showed that the increase in temperature can accelerate the production of ethanol from insulating paper and its pyrolysis intermediate products, which matched the related experimental results. This study can provide an effective reference for the use of ethanol as an indicator to assess the aging condition of the local hot spots of transformers.
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16
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Li J, Zhang F, Zhong Y, Zhao Y, Gao P, Tian F, Zhang X, Zhou R, Cullen PJ. Emerging Food Packaging Applications of Cellulose Nanocomposites: A Review. Polymers (Basel) 2022; 14:polym14194025. [PMID: 36235973 PMCID: PMC9572456 DOI: 10.3390/polym14194025] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/26/2022] [Accepted: 08/31/2022] [Indexed: 12/04/2022] Open
Abstract
Cellulose is the most abundant biopolymer on Earth, which is synthesized by plants, bacteria, and animals, with source-dependent properties. Cellulose containing β-1,4-linked D-glucoses further assembles into hierarchical structures in microfibrils, which can be processed to nanocellulose with length or width in the nanoscale after a variety of pretreatments including enzymatic hydrolysis, TEMPO-oxidation, and carboxymethylation. Nanocellulose can be mainly categorized into cellulose nanocrystal (CNC) produced by acid hydrolysis, cellulose nanofibrils (CNF) prepared by refining, homogenization, microfluidization, sonification, ball milling, and the aqueous counter collision (ACC) method, and bacterial cellulose (BC) biosynthesized by the Acetobacter species. Due to nontoxicity, good biodegradability and biocompatibility, high aspect ratio, low thermal expansion coefficient, excellent mechanical strength, and unique optical properties, nanocellulose is utilized to develop various cellulose nanocomposites through solution casting, Layer-by-Layer (LBL) assembly, extrusion, coating, gel-forming, spray drying, electrostatic spinning, adsorption, nanoemulsion, and other techniques, and has been widely used as food packaging material with excellent barrier and mechanical properties, antibacterial activity, and stimuli-responsive performance to improve the food quality and shelf life. Under the driving force of the increasing green food packaging market, nanocellulose production has gradually developed from lab-scale to pilot- or even industrial-scale, mainly in Europe, Africa, and Asia, though developing cost-effective preparation techniques and precisely tuning the physicochemical properties are key to the commercialization. We expect this review to summarise the recent literature in the nanocellulose-based food packaging field and provide the readers with the state-of-the-art of this research area.
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Affiliation(s)
- Jingwen Li
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China
| | - Feifan Zhang
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China
| | - Yaqi Zhong
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China
| | - Yadong Zhao
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China
- School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
- Correspondence: (Y.Z.); (X.Z.)
| | - Pingping Gao
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China
| | - Fang Tian
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China
| | - Xianhui Zhang
- Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Institute of Electromagnetics and Acoustics, Xiamen University, Xiamen 361005, China
- Correspondence: (Y.Z.); (X.Z.)
| | - Rusen Zhou
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Patrick J. Cullen
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia
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17
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Shi YX, Li SH, Zhao ZP. Molecular simulations of the effects of substitutions on the dissolution properties of amorphous cellulose acetate. Carbohydr Polym 2022; 291:119610. [DOI: 10.1016/j.carbpol.2022.119610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/29/2022] [Accepted: 05/09/2022] [Indexed: 11/17/2022]
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18
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Mechanical Properties and Diffusion Studies in Wax-Cellulose Nanocomposite Packaging Material. Int J Mol Sci 2022; 23:ijms23169501. [PMID: 36012758 PMCID: PMC9409333 DOI: 10.3390/ijms23169501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 08/14/2022] [Accepted: 08/19/2022] [Indexed: 11/23/2022] Open
Abstract
This article focuses on the study related to the estimation of packaging material properties of cellulose–wax nanocomposite using molecular dynamics simulation (MDS). Cellulose based packaging material is gaining lot of importance due to its good material properties and low cost. Cellulose with small amount of plant-derived wax (nonacosane-10-ol and nonacosane-5,10-diol) offers higher mechanical strength and modulus of elasticity compared to the conventional synthetic polymer materials. In this article, in addition to the estimation of mechanical properties, the thermal stability of the proposed ecofriendly cellulose–wax composite is evaluated by estimating the glass transition temperature which essentially provides critical information on the glassy state and rubbery state of this biopolymer. The glass transition temperature of this composite changes significantly compared to that of pure cellulose (which also suffers from poor mechanical strength). Transport properties such as diffusion volume and diffusion coefficient of oxygen, nitrogen, and water are estimated using the results obtained from MDS. The diffusion coefficients of these species within the cellulose–wax composite are analyzed using the diffusion volume and interaction energies of these constituents with the wax and cellulose.
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19
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Liu B, Lv F, Fan X, Li Y, Jiang B. Molecular Dynamics Study of the Influence of Nano SiO2 on the Thermodynamic Properties of PMIA Composites. Polymers (Basel) 2022; 14:polym14153134. [PMID: 35956649 PMCID: PMC9370881 DOI: 10.3390/polym14153134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/25/2022] [Accepted: 07/28/2022] [Indexed: 12/04/2022] Open
Abstract
The poly-m-phenyleneisophthalamide (PMIA) is widely used in the electrical field due to its numerous favorable characteristics, but its poor thermal conductivity limits its application. In this study, PMIA was modified with nano-silica (SiO2) to improve its thermal and mechanical properties. Using iso-phthalic acid and m-phenylenediamine as monomers, the changes in the thermodynamic properties and microstructure parameters of SiO2-modified PMIA were analyzed using molecular dynamics before and after modification in the temperature range of 250~450 K. It was found that adding SiO2 improves the Young’s modulus and Shear modulus of PMIA, and the mechanical properties of PMIA, and SiO2/PMIA composites deteriorate with increasing temperature, but the mechanical properties of SiO2/PMIA composites are always better than those of pure PMIA in the temperature range of electrical equipment. Meanwhile, after doping SiO2 with the radius of 8 Å, the glass transition temperature of PMIA increases by 27.11 K, and its thermal conductivity increases from 0.249 W m−1 K−1 to 0.396 W m−1 K−1. When SiO2 is added to PMIA, the thermal expansion coefficient of PMIA will decrease in both glass and rubber states, and its thermal stability will improve. In terms of microstructure parameters, the free volume distribution of the SiO2/PMIA model is less easily dispersed than that of the PMIA model, indicating that the addition of SiO2 can improve the related properties of PMIA by hindering the movement of molecular chains.
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20
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Lan L, Chen H, Lee D, Xu S, Skillen N, Tedstone A, Robertson P, Garforth A, Daly H, Hardacre C, Fan X. Effect of Ball-Milling Pretreatment of Cellulose on Its Photoreforming for H 2 Production. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2022; 10:4862-4871. [PMID: 35574430 PMCID: PMC9098191 DOI: 10.1021/acssuschemeng.1c07301] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 03/22/2022] [Indexed: 05/05/2023]
Abstract
Photoreforming of cellulose is a promising route for sustainable H2 production. Herein, ball-milling (BM, with varied treatment times of 0.5-24 h) was employed to pretreat microcrystalline cellulose (MCC) to improve its activity in photoreforming over a Pt/TiO2 catalyst. It was found that BM treatment reduced the particle size, crystallinity index (CrI), and degree of polymerization (DP) of MCC significantly, as well as produced amorphous celluloses (with >2 h treatment time). Amorphous cellulose water-induced recrystallization to cellulose II (as evidenced by X-ray diffraction (XRD) and solid-state NMR analysis) was observed in aqueous media. Findings of the work showed that the BM treatment was a simple and effective pretreatment strategy to improve photoreforming of MCC for H2 production, mainly due to the decreased particle size and, specifically in aqueous media, the formation of the cellulose II phase from the recrystallization of amorphous cellulose, the extent of which correlates well with the activity in photoreforming.
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Affiliation(s)
- Lan Lan
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
- E-mail:
| | - Huanhao Chen
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
- State
Key Laboratory of Materials-Oriented Chemical Engineering, College
of Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
| | - Daniel Lee
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Shaojun Xu
- UK
Catalysis Hub, Research Complex at Harwell, Didcot OX11 0FA, United Kingdom
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Nathan Skillen
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
- School
of Chemistry and Chemical Engineering, Queens
University Belfast, Belfast BT9 5AG, United Kingdom
| | - Aleksander Tedstone
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Peter Robertson
- School
of Chemistry and Chemical Engineering, Queens
University Belfast, Belfast BT9 5AG, United Kingdom
| | - Arthur Garforth
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Helen Daly
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
- E-mail:
| | - Christopher Hardacre
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
- E-mail:
| | - Xiaolei Fan
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
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21
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Reishofer D, Resel R, Sattelkow J, Fischer WJ, Niegelhell K, Mohan T, Kleinschek KS, Amenitsch H, Plank H, Tammelin T, Kontturi E, Spirk S. Humidity Response of Cellulose Thin Films. Biomacromolecules 2022; 23:1148-1157. [PMID: 35225593 PMCID: PMC8924868 DOI: 10.1021/acs.biomac.1c01446] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Cellulose–water
interactions are crucial to understand biological
processes as well as to develop tailor made cellulose-based products.
However, the main challenge to study these interactions is the diversity
of natural cellulose fibers and alterations in their supramolecular
structure. Here, we study the humidity response of different, well-defined,
ultrathin cellulose films as a function of industrially relevant treatments
using different techniques. As treatments, drying at elevated temperature,
swelling, and swelling followed by drying at elevated temperatures
were chosen. The cellulose films were prepared by spin coating a soluble
cellulose derivative, trimethylsilyl cellulose, onto solid substrates
followed by conversion to cellulose by HCl vapor. For the highest
investigated humidity levels (97%), the layer thickness increased
by ca. 40% corresponding to the incorporation of 3.6 molecules of
water per anhydroglucose unit (AGU), independent of the cellulose
source used. The aforementioned treatments affected this ratio significantly
with drying being the most notable procedure (2.0 and 2.6 molecules
per AGU). The alterations were investigated in real time with X-ray
reflectivity and quartz crystal microbalance with dissipation, equipped
with a humidity module to obtain information about changes in the
thickness, roughness, and electron density of the films and qualitatively
confirmed using grazing incidence small angle X-ray scattering measurements
using synchrotron irradiation.
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Affiliation(s)
- David Reishofer
- Institute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, Graz 8010, Austria
| | - Roland Resel
- Institute for Solid State Physics, Graz University of Technology, Petersgasse 16, Graz 8010, Austria
| | - Jürgen Sattelkow
- Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, Graz 8010, Austria
| | - Wolfgang J Fischer
- Institute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, Graz 8010, Austria
| | - Katrin Niegelhell
- Institute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, Graz 8010, Austria
| | - Tamilselvan Mohan
- Institute of Chemistry and Technology of Biobased Systems, Graz University of Technology, Stremayrgasse 9, Graz 8010, Austria
| | - Karin Stana Kleinschek
- Institute of Chemistry and Technology of Biobased Systems, Graz University of Technology, Stremayrgasse 9, Graz 8010, Austria
| | - Heinz Amenitsch
- Institute for Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9, Graz 8010, Austria
| | - Harald Plank
- Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, Graz 8010, Austria
| | - Tekla Tammelin
- High Performance Fibre Products, VTT Technical Research Center of Finland Ltd, Espoo FI-02044 VTT, Finland
| | - Eero Kontturi
- Department of Bioproducts and Biosystems, School of Chemical Technology, Aalto University, Espoo 02150, Finland
| | - Stefan Spirk
- Institute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, Graz 8010, Austria
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22
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Nano-Modified Meta-Aramid Insulation Paper with Advanced Thermal, Mechanical, and Electrical Properties. Processes (Basel) 2021. [DOI: 10.3390/pr10010078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Molecular dynamics simulations were used to analyze the internal mechanism for the observed improvement in performance of nano-modified meta-aramid insulation paper from a microscopic point of view. The results showed that the k-polyphenylsilsesquioxane(PPSQ) modified meta-aramid insulation paper was superior to b-PPSQ modified meta-aramid insulation paper in terms of its thermal stability and mechanical and electrical properties. The analysis of microscopic parameters showed that the stiffness of k-PPSQ was less than that of b-PPSQ, and the hydroxyl groups on the open-loop system were more likely to enter the dispersed system, resulting in higher bonding strength, meta-aramid fiber chains between k-PPSQ molecules, and the formation of hydrogen bonds. Additionally, the nano-enhancement effects of k-PPSQ and b-PPSQ resulted in various improvements, including a reduction in pores between molecules in the blend model, an increase in the contact area, the formation of interfacial polarization, and a reduction in defects at the interface.
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23
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French AD. Combining Computational Chemistry and Crystallography for a Better Understanding of the Structure of Cellulose. Adv Carbohydr Chem Biochem 2021; 80:15-93. [PMID: 34872656 DOI: 10.1016/bs.accb.2021.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The approaches in this article seek to enhance understanding of cellulose at the molecular level, independent of the source and the particular crystalline form of cellulose. Four main areas of structure research are reviewed. Initially, the molecular shape is inferred from the crystal structures of many small molecules that have β-(1→4) linkages. Then, conformational analyses with potential energy calculations of cellobiose are covered, followed by the use of Atoms-In-Molecules theory to learn about interactions in experimental and theoretical structures. The last section covers models of cellulose nanoparticles. Controversies addressed include the stability of twofold screw-axis conformations, the influence of different computational methods, the predictability of crystalline conformations by studies of isolated molecules, and the twisting of model cellulose crystals.
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Affiliation(s)
- Alfred D French
- Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, Louisiana, USA
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24
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Zajki-Zechmeister K, Kaira GS, Eibinger M, Seelich K, Nidetzky B. Processive Enzymes Kept on a Leash: How Cellulase Activity in Multienzyme Complexes Directs Nanoscale Deconstruction of Cellulose. ACS Catal 2021; 11:13530-13542. [PMID: 34777910 PMCID: PMC8576811 DOI: 10.1021/acscatal.1c03465] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/11/2021] [Indexed: 12/15/2022]
Abstract
Biological deconstruction of polymer materials gains efficiency from the spatiotemporally coordinated action of enzymes with synergetic function in polymer chain depolymerization. To perpetuate enzyme synergy on a solid substrate undergoing deconstruction, the overall attack must alternate between focusing the individual enzymes locally and dissipating them again to other surface sites. Natural cellulases working as multienzyme complexes assembled on a scaffold protein (the cellulosome) maximize the effect of local concentration yet restrain the dispersion of individual enzymes. Here, with evidence from real-time atomic force microscopy to track nanoscale deconstruction of single cellulose fibers, we show that the cellulosome forces the fiber degradation into the transversal direction, to produce smaller fragments from multiple local attacks ("cuts"). Noncomplexed enzymes, as in fungal cellulases or obtained by dissociating the cellulosome, release the confining force so that fiber degradation proceeds laterally, observed as directed ablation of surface fibrils and leading to whole fiber "thinning". Processive cellulases that are enabled to freely disperse evoke the lateral degradation and determine its efficiency. Our results suggest that among natural cellulases, the dispersed enzymes are more generally and globally effective in depolymerization, while the cellulosome represents a specialized, fiber-fragmenting machinery.
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Affiliation(s)
- Krisztina Zajki-Zechmeister
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Gaurav Singh Kaira
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
| | - Manuel Eibinger
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Klara Seelich
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
| | - Bernd Nidetzky
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 10-12/1, 8010 Graz, Austria
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
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Nakamura M, Islam MS, Rahman MA, Nahar RN, Fukuda M, Sekine Y, Beltramini JN, Kim Y, Hayami S. Microwave aided conversion of cellulose to glucose using polyoxometalate as catalyst. RSC Adv 2021; 11:34558-34563. [PMID: 35494741 PMCID: PMC9042688 DOI: 10.1039/d1ra04426e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 10/19/2021] [Indexed: 11/21/2022] Open
Abstract
The viability of biorefining technology primarily depends on the facile cellulose conversion route with adequate conversion efficiency. Here we have demonstrated the microwave-assisted hydrolysis of cellulose to glucose using polyoxometalate (POM) clusters as acid catalysts. Two different types of POM, including Wells-Dawson and Keggin were justified as catalysts in the cellulose conversion process. In particular, the cellulose to glucose catalytic conversion using Wells-Dawson type POMs has not been reported to date. Also, even though there have been some previous reports about the catalytic biomass conversion of Keggin type POMs, the systematic study to optimize the conversion efficiency in terms of catalyst amount, reaction temperature, reaction time, and the amount of solvent is lacking. Under the experimental conditions employed, the Keggin-type catalyst showed higher cellulose conversion and glucose yield than the Wells-Dawson-type catalyst. Furthermore, the cellulose conversion efficiency and glucose yields were optimized by tuning the reaction conditions including temperature, reaction time, and the amount of solvent. Under optimized conditions, the Keggin-type POM catalyst shows a remarkably high glucose yield of 77.2% and a cellulose conversion of 90.1%. The unique complex properties of the POM catalyst, including being (i) strong acids with extremely high Brønsted and Lewis acidity and (ii) efficient microwave adsorbants which enhanced interaction between substrate and the catalyst can be attributed to the outstanding efficacy of the conversion process.
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Affiliation(s)
- Manami Nakamura
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan
| | - Md Saidul Islam
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan .,Institute of Industrial Nanomaterials (IINa), Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan
| | - Mohammad Atiqur Rahman
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan
| | - Rabin Nurun Nahar
- Institute of Industrial Nanomaterials (IINa), Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan
| | - Masahiro Fukuda
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan
| | - Yoshihiro Sekine
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan .,Priority Organization for Innovation and Excellence, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan
| | - Jorge N Beltramini
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan .,Centre for Tropical Crops and Bio-Commodities, Queensland University of Technology Brisbane 4000 Australia
| | - Yang Kim
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan
| | - Shinya Hayami
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan .,Institute of Industrial Nanomaterials (IINa), Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan.,International Research Center for Agricultural and Environmental Biology (IRCAEB) 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan
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Bregado JL, Tavares FW, Secchi AR, Segtovich ISV. Molecular dynamics of dissolution of a 36-chain cellulose Iβ microfibril at different temperatures above the critical pressure of water. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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27
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Zhou S, Jin K, Buehler MJ. Understanding Plant Biomass via Computational Modeling. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2003206. [PMID: 32945027 DOI: 10.1002/adma.202003206] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/13/2020] [Indexed: 06/11/2023]
Abstract
Plant biomass, especially wood, has been used for structural materials since ancient times. It is also showing great potential for new structural materials and it is the major feedstock for the emerging biorefineries for building a sustainable society. The plant cell wall is a hierarchical matrix of mainly cellulose, hemicellulose, and lignin. Herein, the structure, properties, and reactions of cellulose, lignin, and wood cell walls, studied using density functional theory (DFT) and molecular dynamics (MD), which are the widely used computational modeling approaches, are reviewed. Computational modeling, which has played a crucial role in understanding the structure and properties of plant biomass and its nanomaterials, may serve a leading role on developing new hierarchical materials from biomass in the future.
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Affiliation(s)
- Shengfei Zhou
- Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Mass. Ave 1-290, Cambridge, MA, 02139, USA
| | - Kai Jin
- Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Mass. Ave 1-290, Cambridge, MA, 02139, USA
| | - Markus J Buehler
- Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Mass. Ave 1-290, Cambridge, MA, 02139, USA
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Cellulose-based special wetting materials for oil/water separation: A review. Int J Biol Macromol 2021; 185:890-906. [PMID: 34214576 DOI: 10.1016/j.ijbiomac.2021.06.167] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/19/2021] [Accepted: 06/25/2021] [Indexed: 02/06/2023]
Abstract
Oil spill accidents and oily wastewater discharged by petrochemical industries have severely wasted water resources and damaged the environment. The use of special wetting materials to separate oil and water is efficient and environment-friendly. Cellulose is the most abundant renewable resource and has natural advantages in removing pollutants from oily wastewater. The application and modification of cellulose as special wetting materials have attracted considerable research attention. Therefore, we summarized cellulose-based superlipophilic/superhydrophobic and superhydrophilic/superoleophobic materials exhibiting special wetting properties for oil/water separation. The treatment mechanism, preparation technology, treatment effect, and representative projects of oil-bearing wastewater are discussed. Moreover, cellulose-based intelligent-responsive materials for application to oil/water separation and the removal of other pollutants from oily wastewater have also been summarized. The prospects and potential challenges of all the materials have been highlighted.
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Ren Z, Guo R, Zhou X, Bi H, Jia X, Xu M, Wang J, Cai L, Huang Z. Effect of amorphous cellulose on the deformation behavior of cellulose composites: molecular dynamics simulation. RSC Adv 2021; 11:19967-19977. [PMID: 35479899 PMCID: PMC9033998 DOI: 10.1039/d1ra02625a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 05/19/2021] [Indexed: 11/21/2022] Open
Abstract
This study was aimed at predicting and enhancing the properties of the blend, as well as exploring the mechanism, of a polylactic acid (PLA)/amorphous cellulose composite system through molecular characterization. The static properties of the amorphous cellulose/PLA blend model and the mechanical response of the material under uniaxial tension were studied by molecular dynamics simulation to establish the structure-property relationship. PLA and cellulose showed poor miscibility, the change in the compatibility of the mixture can be attributed to the hydrogen bond interaction between the cellulose and PLA functional groups. The radius of gyration, interaction and free volume of the molecular chain in the blend were analyzed. The conformational changes under tensile deformation indicated that the load-bearing role of cellulose in the system was the main reason for increasing the strength of the material. The yield process was considered to be the infiltration of free volume caused by deformation.
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Affiliation(s)
- Zechun Ren
- Material Science and Engineering College, Northeast Forestry University Harbin 150040 China
| | - Rui Guo
- Material Science and Engineering College, Northeast Forestry University Harbin 150040 China
| | - Xinyuan Zhou
- Material Science and Engineering College, Northeast Forestry University Harbin 150040 China
| | - Hongjie Bi
- Material Science and Engineering College, Northeast Forestry University Harbin 150040 China
| | - Xin Jia
- Material Science and Engineering College, Northeast Forestry University Harbin 150040 China
| | - Min Xu
- Material Science and Engineering College, Northeast Forestry University Harbin 150040 China
| | - Jun Wang
- Civil Engineering College, Northeast Forestry University Harbin 150040 China
| | - Liping Cai
- Mechanical Engineering Department, University of North Texas Denton TX 76201 USA.,College of Materials Science and Engineering, Nanjing Forestry University Nanjing 210037 China
| | - Zhenhua Huang
- Mechanical Engineering Department, University of North Texas Denton TX 76201 USA
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30
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Molecular Simulation of Improved Mechanical Properties and Thermal Stability of Insulation Paper Cellulose by Modification with Silane-Coupling-Agent-Grafted Nano-SiO2. Processes (Basel) 2021. [DOI: 10.3390/pr9050766] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Cellulose is an important part of transformer insulation paper. Thermal aging of cellulose occurs in long-term operation of transformers, which deteriorates the mechanical properties and thermal stability of cellulose, resulting in a decrease in the transformer life. Therefore, improvement of the mechanical properties and thermal stability of cellulose has become a research hotspot. In this study, the effects of different silane coupling agents on the mechanical properties and thermal stability of modified cellulose were studied. The simulation results showed that the mechanical parameters of cellulose are only slightly improved by KH560 (γ-glycidyl ether oxypropyl trimethoxysilane) and KH570 (γ-methylacrylloxy propyl trimethoxy silane) modified nano-SiO2, while the mechanical parameters of cellulose are greatly improved by KH550 (γ-aminopropyl triethoxy silane) and KH792 (N-(2-aminoethyl)-3-amino propyl trimethoxy silane) modified nano-SiO2. The glass-transition temperature of the composite model is 24 K higher than that of the unmodified model. The mechanism of the change of the glass-transition temperature was analyzed from the point of view of free-volume theory. The main reason for the change of the glass-transition temperature is that the free volume abruptly changes, which increases the space for movement of the cellulose chain and accelerates the whole movement of the molecular chain. Therefore, modifying cellulose with KH792-modified nano-SiO2 can significantly enhance the thermal stability of cellulose.
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31
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Wei Y, Han W, Li G, Liang X, Gu Z, Hu K. Aging Characteristics of Transformer Oil-Impregnated Insulation Paper Based on Trap Parameters. Polymers (Basel) 2021; 13:polym13091364. [PMID: 33921999 PMCID: PMC8122526 DOI: 10.3390/polym13091364] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/29/2022] Open
Abstract
Oil-impregnated insulation paper is an important part of transformers; its performance seriously affects the life of power equipment. It is of significance to study the aging characteristics and mechanism of oil-impregnated insulation paper under thermal stress for transformer status detection and evaluation. In the work, the accelerated thermal aging was carried out at 120 °C, and DP1490, DP787, and DP311 samples were selected to represent the new, mid-aging, and late-aging status of the transformer, respectively. The space charge distribution within the specimens was measured by the pulsed electro-acoustic (PEA) method and the trap parameters were extracted based on the measurement curves. Further, the aging mechanism was studied by molecular simulation technology. A typical molecular chain defect model was constructed to study the motion of cellulose molecules under thermal stress. The experimental results show that the corresponding trap energy levels are 0.54 eV, 0.73 eV, and 0.92 eV for the new specimen, the mid-aging specimen, and the late aging specimen, respectively. The simulation results show that the trapped energy at the beginning of aging is mainly determined by the loss of H atoms. The changes in trap energy in the middle stage of aging are mainly caused by the absence of some C atoms, and the trap energy level at the end of aging is mainly caused by the breakage of chemical bonds. This study is of great significance to reveal the aging mechanism of oil-impregnated insulation paper and the modification of insulation paper.
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Liu X, Yan P, Xu Z, Zhang ZC. The effect of mix-milling with P 2O 5 on cellulose physicochemical properties responsible for increased glucose yield. Carbohydr Polym 2021; 258:117652. [PMID: 33593540 DOI: 10.1016/j.carbpol.2021.117652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/07/2021] [Accepted: 01/11/2021] [Indexed: 10/22/2022]
Abstract
Breaking the recalcitrant structure of native crystalline cellulose is an energy demanding rate liming step in the production of glucose from cellulosic biomass. Mix-milling of lignocellulosic substrates (with P2O5) dramatically increased glucose yield. In this work, the changes of physicochemical characteristics (morphology, structure, degree of polymerization (DP), solubility) of cellulose during mix-milling (with P2O5) are correlated with glucose yield in the subsequent chemical hydrolysis process. The mix-milling enables highly efficient breakdown of cellulose I crystalline to smaller amorphous particles with low DP, which is recrystallized into cellulose II structure after water-wetting. As a result, the mix-milled cellulose (MMC) shows higher hydrolysis reactivity than that of single-milled cellulose (SMC). The results showed that small particle size, low DP, higher solubility and cellulose II content are correlated with the hydrolysis reactivity of cellulose.
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Affiliation(s)
- Xiumei Liu
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China
| | - Peifang Yan
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China
| | - Zhanwei Xu
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China
| | - Z Conrad Zhang
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China.
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33
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Ponnuchamy V, Sandak A, Sandak J. Multiscale modelling investigation of wood modification with acetic anhydride. Phys Chem Chem Phys 2020; 22:28448-28458. [PMID: 33306769 DOI: 10.1039/d0cp05165a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Density functional theory (DFT) and molecular dynamics (MD) simulations were employed to investigate the interaction of cellulose and lignin with acetic anhydride for explaining the wood modification process. Cellulose was modelled with a cellobiose unit and dibenzodioxocin was used to represent the lignin model. Results obtained from both methods revealed that acetic anhydride interacted substantially more with the cellobiose model than the lignin model. The interaction energy of cellobiose-acetic anhydride was higher (about 20 kJ mol-1) than that of lignin-acetic anhydride. DFT results on hydrogen bonding indicated that the hydroxyl group from cellobiose and the aromatic hydroxyl group from lignin models have similar energy values, which explain the equal strength of hydrogen bond interaction. The same trend was also obtained for the substitution of acetyl group in the hydroxyl group. MD results have also predicted that acetic anhydride forms a stronger interaction with cellobiose than with the lignin model, and these findings were in agreement with the DFT results.
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34
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Dan L, Huang Z, Li J, Wang Q, Chen G, He J. Molecular dynamics simulations of performance degradation of cellulose nanofibers (CNFs) under hygrothermal environments. MOLECULAR SIMULATION 2020. [DOI: 10.1080/08927022.2020.1807541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Linyang Dan
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, People’s Republic of China
| | - Zhengyong Huang
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, People’s Republic of China
| | - Jian Li
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, People’s Republic of China
| | - Qiang Wang
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, People’s Republic of China
| | - Gang Chen
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, People’s Republic of China
| | - JianFeng He
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, People’s Republic of China
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35
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Zhang Y, Yin M, Li L, Fan B, Liu Y, Li R, Ren X, Huang TS, Kim IS. Construction of aerogels based on nanocrystalline cellulose and chitosan for high efficient oil/water separation and water disinfection. Carbohydr Polym 2020; 243:116461. [DOI: 10.1016/j.carbpol.2020.116461] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 05/10/2020] [Accepted: 05/14/2020] [Indexed: 11/15/2022]
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36
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Investigation on the Interaction between Cellulosic Paper and Organic Acids Based on Molecular Dynamics. Molecules 2020; 25:molecules25173938. [PMID: 32872243 PMCID: PMC7504618 DOI: 10.3390/molecules25173938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/24/2020] [Accepted: 08/24/2020] [Indexed: 11/25/2022] Open
Abstract
Organic acid is an important factor that accelerates the aging of cellulosic insulation materials. In this study, the interactions between cellulose and five acids, representative of what may be found in an aging transformer, were studied using molecular dynamics. The adsorption process of the five acids onto the surface of crystalline cellulose shows that the three low molecular acids are more readily adsorbed onto cellulose than the two high molecular acids. The deformation and adsorption energies of the acids all increase with an increase in molecular weight when they are stably interacting with cellulose. However, the differences between adsorption energies and deformation energies are positive for the three low molecular acids, whereas they are negative for the two high molecular acids. This indicates that the attachments onto cellulose of low molecular acids are considerably more stabilized than those of the high molecular acids. This is consistent with the experimental results. Furthermore, based on the calculated solubility parameters of acids, the experimental result that the three low molecular acids are to a large degree absorbed onto the cellulose, whereas the two high molecular acids remain in the oil, was theoretically elucidated using the theory of similarity and intermiscibility.
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37
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Bregado JL, Tavares FW, Secchi AR, Segtovich ISV. Thermophysical Properties of Amorphous‐Paracrystalline Celluloses by Molecular Dynamics. MACROMOL THEOR SIMUL 2020. [DOI: 10.1002/mats.202000007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jurgen Lange Bregado
- Programa de Engenharia Química/COPPEUniversidade Federal do Rio de JaneiroCidade Universitária Rio de Janeiro CP 21941‐914 Brazil
| | - Frederico Wanderley Tavares
- Programa de Engenharia Química/COPPEUniversidade Federal do Rio de JaneiroCidade Universitária Rio de Janeiro CP 21941‐914 Brazil
- Escola de QuímicaDepartamento de Engenharia QuímicaUniversidade Federal do Rio de JaneiroCidade Universitária Rio de Janeiro CP 21941‐972 Brazil
| | - Argimiro Resende Secchi
- Programa de Engenharia Química/COPPEUniversidade Federal do Rio de JaneiroCidade Universitária Rio de Janeiro CP 21941‐914 Brazil
- Escola de QuímicaDepartamento de Engenharia QuímicaUniversidade Federal do Rio de JaneiroCidade Universitária Rio de Janeiro CP 21941‐972 Brazil
| | - Iuri Soter Viana Segtovich
- Programa de Engenharia Química/COPPEUniversidade Federal do Rio de JaneiroCidade Universitária Rio de Janeiro CP 21941‐914 Brazil
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38
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Gurina D, Surov O, Voronova M, Zakharov A. Molecular Dynamics Simulation of Polyacrylamide Adsorption on Cellulose Nanocrystals. NANOMATERIALS 2020; 10:nano10071256. [PMID: 32605224 PMCID: PMC7408107 DOI: 10.3390/nano10071256] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 11/20/2022]
Abstract
Classical molecular dynamics simulations of polyacrylamide (PAM) adsorption on cellulose nanocrystals (CNC) in a vacuum and a water environment are carried out to interpret the mechanism of the polymer interactions with CNC. The structural behavior of PAM is studied in terms of the radius of gyration, atom–atom radial distribution functions, and number of hydrogen bonds. The structural and dynamical characteristics of the polymer adsorption are investigated. It is established that in water the polymer macromolecules are mainly adsorbed in the form of a coil onto the CNC facets. It is found out that water and PAM sorption on CNC is a competitive process, and water weakens the interaction between the polymer and CNC.
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Affiliation(s)
- Darya Gurina
- Correspondence: (D.G.); (O.S.); Tel.: +7-493-2351-869 (D.G.); +7-493-2351-545 (O.S.)
| | - Oleg Surov
- Correspondence: (D.G.); (O.S.); Tel.: +7-493-2351-869 (D.G.); +7-493-2351-545 (O.S.)
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39
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Nanocellulose for Stabilization of Pickering Emulsions and Delivery of Nutraceuticals and Its Interfacial Adsorption Mechanism. FOOD BIOPROCESS TECH 2020. [DOI: 10.1007/s11947-020-02481-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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40
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Chen Y, Jiang X, Wu H, Zheng L. Thermal behavior of complex model with the cellulose II and amorphous chain. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2020. [DOI: 10.1142/s0219633620400040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
To investigate the thermal behavior of complex model with amorphous region and crystallization region of cellulose II, the structures and properties of cellulose II, amorphous chain and their combined models were studied by molecular dynamics simulation. The results showed that the amorphous chain is more susceptible to temperature than the cellulose II. It can form anti-parallel structure similar to cellulose II at high temperature. In the complex model, one end of the amorphous chain is fixed to form hydrogen bonds with the cellulose II, and the other end is not. At 300[Formula: see text]K, the free part of amorphous chain is approximately perpendicular to the axial direction of the cellulose II. When the temperature increases, the free part of amorphous chain adheres to the surface of cellulose II. The free part of amorphous chain did not form hydrogen bond with the cellulose II. The formation of amorphous chain and surface of the cellulose II is a zipper process at 450[Formula: see text]K. Furthermore, water molecules penetrate into the inter-space of the amorphous and crystalline regions. The probability of hydrogen bonds between water molecules and the complex model was less than 8.21% which explains why cellulose is insoluble in water. These conclusions provide a guiding significance for the dissolution mechanism of cellulose.
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Affiliation(s)
- Yu Chen
- Wuhan Textile and Apparel Digital Engineering, Technology Research Center Wuhan Textile University, Wuhan, Hubei 430073, P. R. China
| | - Xuewei Jiang
- Wuhan Textile and Apparel Digital Engineering, Technology Research Center Wuhan Textile University, Wuhan, Hubei 430073, P. R. China
| | - Huhe Wu
- Wuhan Textile and Apparel Digital Engineering, Technology Research Center Wuhan Textile University, Wuhan, Hubei 430073, P. R. China
| | - Lu Zheng
- Wuhan Textile and Apparel Digital Engineering, Technology Research Center Wuhan Textile University, Wuhan, Hubei 430073, P. R. China
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41
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Wu Z, Beltran-Villegas DJ, Jayaraman A. Development of a New Coarse-Grained Model to Simulate Assembly of Cellulose Chains Due to Hydrogen Bonding. J Chem Theory Comput 2020; 16:4599-4614. [DOI: 10.1021/acs.jctc.0c00225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Zijie Wu
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy
St., Newark, Delaware 19716, United States
| | - Daniel J. Beltran-Villegas
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy
St., Newark, Delaware 19716, United States
| | - Arthi Jayaraman
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy
St., Newark, Delaware 19716, United States
- Department of Materials Science and Engineering, University of Delaware, 201 DuPont Hall, Newark, Delaware 19716, United States
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42
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Che KM, Zhang MZ, He JL, Ni PH. Polyphosphoester-modified Cellulose Nanocrystals for Stabilizing Pickering Emulsion Polymerization of Styrene. CHINESE JOURNAL OF POLYMER SCIENCE 2020. [DOI: 10.1007/s10118-020-2404-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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A Case Study about Biomass Torrefaction on an Industrial Scale: Solutions to Problems Related to Self-Heating, Difficulties in Pelletizing, and Excessive Wear of Production Equipment. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10072546] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The search for different forms of biomass that can be used as an alternative to those more traditional ones has faced numerous difficulties, namely those related to disadvantages that the majority of residual forms present. However, these residual forms of biomass also have advantages, namely the fact that, by being outside the usual biomass supply chains for energy, they are usually much cheaper, and therefore contribute to a significant reduction in production costs. To improve the less-favorable properties of these biomasses, thermochemical conversion technologies, namely torrefaction, are presented as a way to improve the combustibility of these materials. However, it is a technology that has not yet demonstrated its full potential, mainly due to difficulties in the process of scale-up and process control. In this article it is intended to present the experience obtained over 5 years in the operation of a biomass torrefaction plant with an industrial pilot scale, where all the difficulties encountered and how they were corrected are presented, until it became a fully operational plant. This article, in which a real case study is analyzed, presents in a descriptive way all the work done during the time from when the plant started up and during the commissioning period until the state of continuous operation had been reached.
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Ganguly K, Patel DK, Dutta SD, Shin WC, Lim KT. Stimuli-responsive self-assembly of cellulose nanocrystals (CNCs): Structures, functions, and biomedical applications. Int J Biol Macromol 2020; 155:456-469. [PMID: 32222290 DOI: 10.1016/j.ijbiomac.2020.03.171] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/05/2020] [Accepted: 03/19/2020] [Indexed: 02/06/2023]
Abstract
Cellulose nanocrystals (CNCs) have received a significant amount of attention from the researchers. It is used as a nanomaterial for various applications due to its excellent physiochemical properties for the last few decades. Self-assembly is a phenomenon where autonomous reorganization of randomly oriented species occurs elegantly. Self-assembly is responsible for the formation of the hierarchical cholesteric structure of CNCs. This process is highly influenced by several factors, such as the surface chemistry of the nanoparticles, intermolecular forces, and the fundamental laws of thermodynamics. Various conventional experimental designs and molecular dynamics (MD) studies have been applied to determine the possible mechanism of self-assembly in CNCs. Different external factors, like pH, temperature, magnetic/electric fields, vacuum, also influence the self-assembly process in CNCs. Notably, better responses have been observed in CNCs-grafted polymer nanocomposites. These functionalized CNCs with stimuli-responsive self-assembly have immense practical applications in modern biotechnology and medicine. Herein, we have concisely discussed the mechanism of the self-assembled CNCs in the presence of different external factors such as pH, temperature, electric/magnetic fields, and their biomedical applications.
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Affiliation(s)
- Keya Ganguly
- Department of Biosystems Engineering, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Dinesh K Patel
- Department of Biosystems Engineering, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Sayan Deb Dutta
- Department of Biosystems Engineering, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Woo-Chul Shin
- Department of Biosystems Engineering, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Ki-Taek Lim
- Department of Biosystems Engineering, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea.
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Tensile behaviour of dislocated/crystalline cellulose fibrils at the nano scale. Carbohydr Polym 2020; 235:115946. [PMID: 32122482 DOI: 10.1016/j.carbpol.2020.115946] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/31/2020] [Accepted: 02/02/2020] [Indexed: 11/23/2022]
Abstract
Atomistic modelling of cellulose has widely been investigated for years using molecular dynamics simulations. In this paper, we model Iβ crystalline cellulose as well as develop a model including dislocations in between the crystal regions. The model including dislocations shows a tensile modulus of 109 GPa, 25% lower than that of the fully crystalline model (146 GPa). The change in dihedral angle preferences is analysed, and its effect on hydrogen bonding pattern is assessed. How presence of hydrogen bonds contributes to elastic properties of cellulose nano-fibrils is shown. Effect of water on the elastic modulus of fibrils is also investigated. Moreover, an illustration is given of how the tensile behaviour of fibrils is controlled by a synergy between the geometry changes occurring at the glycosidic linkage, reflected by specific torsional and glycosidic angles. These findings can be useful in further modelling of cellulosic fibrils at the atomistic and coarse-grained scales.
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46
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A Molecular Dynamics Study of the Generation of Ethanol for Insulating Paper Pyrolysis. ENERGIES 2020. [DOI: 10.3390/en13010265] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cellulosic insulation paper is usually used in oil-immersed transformer insulation systems. In this study, the molecular dynamics method based on reaction force field (ReaxFF) was used to simulate the pyrolysis process of a cellobiose molecular model. Through a series of ReaxFF- Molecular Dynamics (MD) simulations, the generation path of ethanol at the atomic level was studied. Because the molecular system has hydrogen bonding, force-bias Monte Carlo (fbMC) is mixed into ReaxFF to reduce the cost of calculation by reducing the sampled data. In order to ensure the reliability of the simulation, a model composed of 20 cellobioses and a model composed of 40 cellobioses were respectively established for repeated simulation in the range of 500–3000 K. The results show that insulating paper produced ethanol at extreme thermal fault, and the intermediate product of vinyl alcohol is the key to the aging process. It is also basically consistent with others’ previous experiment results. So it can provide an effective reference for the use of ethanol as an indicator to evaluate the aging condition of transformers.
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Zhang J, Tang C, Wang Q, Liu X, Du D. Analysis of nano-SiO2 affecting the acids diffusion in the interface between oil and cellulose paper. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2019.110557] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Zhai C, Li T, Shi H, Yeo J. Discovery and design of soft polymeric bio-inspired materials with multiscale simulations and artificial intelligence. J Mater Chem B 2020; 8:6562-6587. [DOI: 10.1039/d0tb00896f] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Establishing the “Materials 4.0” paradigm requires intimate knowledge of the virtual space in materials design.
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Affiliation(s)
- Chenxi Zhai
- J2 Lab for Engineering Living Materials
- Sibley School of Mechanical and Aerospace Engineering
- Cornell University
- Ithaca
- USA
| | - Tianjiao Li
- J2 Lab for Engineering Living Materials
- Sibley School of Mechanical and Aerospace Engineering
- Cornell University
- Ithaca
- USA
| | - Haoyuan Shi
- J2 Lab for Engineering Living Materials
- Sibley School of Mechanical and Aerospace Engineering
- Cornell University
- Ithaca
- USA
| | - Jingjie Yeo
- J2 Lab for Engineering Living Materials
- Sibley School of Mechanical and Aerospace Engineering
- Cornell University
- Ithaca
- USA
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Differences in protein structural regions that impact functional specificity in GT2 family β-glucan synthases. PLoS One 2019; 14:e0224442. [PMID: 31665152 PMCID: PMC6821405 DOI: 10.1371/journal.pone.0224442] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/14/2019] [Indexed: 12/16/2022] Open
Abstract
Most cell wall and secreted β-glucans are synthesised by the CAZy Glycosyltransferase 2 family (www.cazy.org), with different members catalysing the formation of (1,4)-β-, (1,3)-β-, or both (1,4)- and (1,3)-β-glucosidic linkages. Given the distinct physicochemical properties of each of the resultant β-glucans (cellulose, curdlan, and mixed linkage glucan, respectively) are crucial to their biological and biotechnological functions, there is a desire to understand the molecular evolution of synthesis and how linkage specificity is determined. With structural studies hamstrung by the instability of these proteins to solubilisation, we have utilised in silico techniques and the crystal structure for a bacterial cellulose synthase to further understand how these enzymes have evolved distinct functions. Sequence and phylogenetic analyses were performed to determine amino acid conservation, both family-wide and within each sub-family. Further structural analysis centred on comparison of a bacterial curdlan synthase homology model with the bacterial cellulose synthase crystal structure, with molecular dynamics simulations performed with their respective β-glucan products bound in the trans-membrane channel. Key residues that differentially interact with the different β-glucan chains and have sub-family-specific conservation were found to reside at the entrance of the trans-membrane channel. The linkage-specific catalytic activity of these enzymes and hence the type of β-glucan chain built is thus likely determined by the different interactions between the proteins and the first few glucose residues in the channel, which in turn dictates the position of the acceptor glucose. The sequence-function relationships for the bacterial β-glucan synthases pave the way for extending this understanding to other kingdoms, such as plants.
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Buchtová N, Pradille C, Bouvard JL, Budtova T. Mechanical properties of cellulose aerogels and cryogels. SOFT MATTER 2019; 15:7901-7908. [PMID: 31535679 DOI: 10.1039/c9sm01028a] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Highly porous and lightweight cellulose materials were prepared via dissolution-coagulation and different drying routes. Cellulose of three different molecular weights was dissolved in an ionic liquid/dimethyl sulfoxide mixture. Drying was performed either with supercritical CO2 resulting in "aerogels", or via freeze-drying resulting in "cryogels". The influence of cellulose molecular weight, concentration and drying method on the morphology, density, porosity and specific surface area was determined. The mechanical properties of cellulose cryogels and aerogels under uniaxial compression were studied in detail and analyzed in the view of existing models developed for porous materials. It was demonstrated that the Poisson's ratio of cellulose aerogels is not equal to zero, contrary to what is usually reported in the literature, but decreases with an increase in density. Compressive modulus and yield stress of cryogels turned out to be higher than those of aerogels taken at the same density. This was interpreted by the different morphology of the porous materials studied.
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Affiliation(s)
- Nela Buchtová
- MINES ParisTech, CEMEF - Centre de Mise en Forme des Matériaux, CNRS UMR 7635, PSL Research University, CS 10207 rue Claude Daunesse, 06904 Sophia Antipolis, France.
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