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Hamal EK, Alfassi G, Khalfin R, Rein DM, Cohen Y. Structural Insights into Cellulose-Coated Oil in Water Emulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11171-11179. [PMID: 36069748 PMCID: PMC9494939 DOI: 10.1021/acs.langmuir.2c00947] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Cellulose is a renewable biopolymer, abundant on Earth, with a multi-level supramolecular structure. There has been significant interest and advancement in utilizing natural cellulose to stabilize emulsions. In our research, we develop and examine oil in water emulsions surrounded by unmodified cellulose as microreactors for the process of transformation of cellulose into valuable chemicals such as biodiesel. This study presents morphological characterization of cellulose-coated emulsions that can be used for such purposes. Cryogenic-scanning electron microscopy imaging along with light microscopy and light scattering reveals a multi-layer inner structure: an oil core surrounded by a porous cellulose hydrogel shell, coated by an outer shell of regenerated cellulose. Measurements of small-angle X-ray scattering provide quantification of the nano-scale structure within the porous cellulose hydrogel inner shell of the emulsion particle. These characteristics are relevant to utilization of cellulose-coated emulsions in various applications such as controlled release and as hosts for enzymatic biotechnological reactions.
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Affiliation(s)
- Ester Korkus Hamal
- Department
of Chemical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
- Email
address:
| | - Gilad Alfassi
- Department
of Biotechnology Engineering, ORT Braude
College, Karmiel 2161002, Israel
| | - Rafail Khalfin
- Department
of Chemical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
| | - Dmitry M. Rein
- Department
of Chemical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
| | - Yachin Cohen
- Department
of Chemical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
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2
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Lefroy KS, Murray BS, Ries ME. Relationship between size and cellulose content of cellulose microgels (CMGs) and their water-in-oil emulsifying capacity. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128926] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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3
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Lefroy KS, Murray BS, Ries ME. Rheological and NMR Studies of Cellulose Dissolution in the Ionic Liquid BmimAc. J Phys Chem B 2021; 125:8205-8218. [PMID: 34279933 DOI: 10.1021/acs.jpcb.1c02848] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Solutions of two types of cellulose in the ionic liquid 1-butyl-3-methyl-imidazolium acetate (BmimAc) have been analyzed using rheology and fast-field cycling nuclear magnetic resonance (NMR) spectroscopy, in order to analyze the macroscopic (bulk) and microscopic environments, respectively. The degree of polymerization (DP) was observed to have a significant effect on both the overlap (c*) and entanglement (ce) concentrations and the intrinsic viscosity ([η]). For microcrystalline cellulose (MCC)/BmimAc solutions, [η] = 116 mL g-1, which is comparable to that of MCC/1-ethyl-3-methyl-imidazolium acetate (EmimAc) solutions, while [η] = 350 mL g-1 for the commercial cellulose (higher DP). Self-diffusion coefficients (D) obtained via the model-independent approach were found to decrease with cellulose concentration and increase with temperature, which can in part be explained by the changes in viscosity; however, ion interactions on a local level are also important. Both Stokes-Einstein and Stokes-Einstein-Debye analyses were carried out to directly compare rheological and relaxometry analyses. It was found that polymer entanglements affect the microscopic environment to a much lesser extent than for the macroscopic environment. Finally, the temperature dependencies of η, D, and relaxation time (T1) could be well described by Arrhenius relationships, and thus, activation energies (Ea) for flow, diffusion, and relaxation were determined. We demonstrate that temperature and cellulose concentration have different effects on short- and long-range interactions.
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Affiliation(s)
- Katherine S Lefroy
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, U.K
| | - Brent S Murray
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, U.K
| | - Michael E Ries
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
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4
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H 2S Removal from Groundwater by Chemical Free Advanced Oxidation Process Using UV-C/VUV Radiation. Molecules 2021; 26:molecules26134016. [PMID: 34209266 PMCID: PMC8271645 DOI: 10.3390/molecules26134016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 11/17/2022] Open
Abstract
Sulfide species may be present in groundwater due to natural processes or due to anthropogenic activity. H2S contamination poses odor nuisance and may also lead to adverse health effects. Advanced oxidation processes (AOPs) are considered promising treatments for hydrogen-sulfide removal from water, but conventional AOPs usually require continuous chemical dosing, as well as post-treatment, when solid catalysts are applied. Vacuum-UV (VUV) radiation can generate ·OH in situ via water photolysis, initiating chemical-free AOP. The present study investigated the applicability of VUV-based AOP for removal of H2S both in synthetic solutions and in real groundwater, comparing combined UV-C/VUV and UV-C only radiation in a continuous-flow reactor. In deionized water, H2S degradation was much faster under the combined radiation, dominated by indirect photolysis, and indicated the formation of sulfite intermediates that convert to sulfate at high radiation doses. Sulfide was efficiently removed from natural groundwater by the two examined lamps, with no clear preference between them. However, in anoxic conditions, common in sulfide-containing groundwater, a small advantage for the combined lamp was observed. These results demonstrate the potential of utilizing VUV-based AOP for treating H2S contamination in groundwater as a chemical-free treatment, which can be especially attractive to remote small treatment facilities.
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5
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Courtenay JC, Jin Y, Schmitt J, Hossain KMZ, Mahmoudi N, Edler KJ, Scott JL. Salt-Responsive Pickering Emulsions Stabilized by Functionalized Cellulose Nanofibrils. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6864-6873. [PMID: 34081858 DOI: 10.1021/acs.langmuir.0c03306] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Oil-in-water emulsions have been stabilized by functionalized cellulose nanofibrils bearing either a negative (oxidized cellulose nanofibrils, OCNF) or a positive (cationic cellulose nanofibrils, CCNF) surface charge. The size of the droplets was measured by laser diffraction, while the structure of the shell of the Pickering emulsion droplets was probed using small-angle neutron scattering (SANS), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and rheology measurements. Both OCNF- and CCNF-stabilized emulsions present a very thick shell (>100 nm) comprised of densely packed CNF. OCNF-stabilized emulsions proved to be salt responsive, influencing the droplet aggregation and ultimately the gel properties of the emulsions, while CCNF emulsions, on the other hand, showed very little salt-dependent behavior.
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Affiliation(s)
- James C Courtenay
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
- Centre for Sustainable Chemical Technologies, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Yun Jin
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Julien Schmitt
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
- LSFC, Laboratoire de Synthèse et Fonctionnalisation des Céramiques, UMR 3080 CNRS/Saint-Gobain CREE, Saint-Gobain Research Provence, 550 Avenue Alphonse Jauffret, Cavaillon 84300, France
| | - Kazi M Zakir Hossain
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Najet Mahmoudi
- ISIS Neutron & Muon Source, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Karen J Edler
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Janet L Scott
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
- Centre for Sustainable Chemical Technologies, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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6
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Phoon PY, Henry CJ. Fibre-based oleogels: effect of the structure of insoluble fibre on its physical properties. Food Funct 2020; 11:1349-1361. [PMID: 32057036 DOI: 10.1039/c9fo02431j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Solid fat is a "staple" in the modern diet in the form of products such as butter, margarine, and shortening. Due to its potentially detrimental effects on health, numerous dietary guidelines recommend its restriction. This opens up opportunities to develop fat replacers via edible oil structuring. In this study, we report the development of a unique, non-thermal method to create oleogels which contain only natural food fibres and liquid vegetable oil. Moreover, they do not oil off on compression. The objective was to understand how the structure of insoluble fibre influenced the physical properties of oleogels, specifically physical robustness and apparent melting point. The fibres studied were citrus fibre of different particle sizes, and nata de coco fibre known for its thinner dimension and finer three-dimensional structure. The melting characteristics of oleogels were studied by differential scanning calorimetry and visual observation. The physical robustness of oleogels was characterised by the spreadability method using a texture analyser. The presence of fibre was found to disrupt fat crystallisation, leading to proportionately more crystal species that were less stable. However, the true melting point of fat was not significantly altered. Despite greater disruption, oleogels made with longer and/or more extensive fibres were mainly firmer and capable of keeping the oil in the solid oleogel form, even under elevated temperatures. Our novel approach for manufacturing oleogels opens up a range of opportunities for their application in various products and systems.
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Affiliation(s)
- Pui Yeu Phoon
- Clinical Nutrition Research Centre (CNRC), Agency for Science, Technology and Research (A*STAR). MD 6 Building, 14 Medical Drive #07-02, Singapore 117599.
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7
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Production and technological characteristics of avocado oil emulsions stabilized with cellulose nanofibrils isolated from agroindustrial residues. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2019.124263] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Costa C, Mira I, Benjamins JW, Lindman B, Edlund H, Norgren M. Interfacial activity and emulsion stabilization of dissolved cellulose. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111325] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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9
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Costa C, Medronho B, Filipe A, Mira I, Lindman B, Edlund H, Norgren M. Emulsion Formation and Stabilization by Biomolecules: The Leading Role of Cellulose. Polymers (Basel) 2019; 11:E1570. [PMID: 31561633 PMCID: PMC6835308 DOI: 10.3390/polym11101570] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 09/23/2019] [Accepted: 09/23/2019] [Indexed: 01/28/2023] Open
Abstract
Emulsion stabilization by native cellulose has been mainly hampered because of its insolubility in water. Chemical modification is normally needed to obtain water-soluble cellulose derivatives. These modified celluloses have been widely used for a range of applications by the food, cosmetic, pharmaceutic, paint and construction industries. In most cases, the modified celluloses are used as rheology modifiers (thickeners) or as emulsifying agents. In the last decade, the structural features of cellulose have been revisited, with particular focus on its structural anisotropy (amphiphilicity) and the molecular interactions leading to its resistance to dissolution. The amphiphilic behavior of native cellulose is evidenced by its capacity to adsorb at the interface between oil and aqueous solvent solutions, thus being capable of stabilizing emulsions. In this overview, the fundamentals of emulsion formation and stabilization by biomolecules are briefly revisited before different aspects around the emerging role of cellulose as emulsion stabilizer are addressed in detail. Particular focus is given to systems stabilized by native cellulose, either molecularly-dissolved or not (Pickering-like effect).
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Affiliation(s)
- Carolina Costa
- FSCN, Surface and Colloid Engineering, Mid Sweden University, SE-851 70 Sundsvall, Sweden; (C.C.); (B.L.); (H.E.)
| | - Bruno Medronho
- FSCN, Surface and Colloid Engineering, Mid Sweden University, SE-851 70 Sundsvall, Sweden; (C.C.); (B.L.); (H.E.)
- Faculty of Sciences and Technology (MeditBio), Ed. 8, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal;
| | - Alexandra Filipe
- Faculty of Sciences and Technology (MeditBio), Ed. 8, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal;
| | - Isabel Mira
- RISE, Bioscience and Materials, SE-114 28 Stockholm, Sweden;
| | - Björn Lindman
- FSCN, Surface and Colloid Engineering, Mid Sweden University, SE-851 70 Sundsvall, Sweden; (C.C.); (B.L.); (H.E.)
| | - Håkan Edlund
- FSCN, Surface and Colloid Engineering, Mid Sweden University, SE-851 70 Sundsvall, Sweden; (C.C.); (B.L.); (H.E.)
| | - Magnus Norgren
- FSCN, Surface and Colloid Engineering, Mid Sweden University, SE-851 70 Sundsvall, Sweden; (C.C.); (B.L.); (H.E.)
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10
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Medronho B, Filipe A, Costa C, Romano A, Lindman B, Edlund H, Norgren M. Microrheology of novel cellulose stabilized oil-in-water emulsions. J Colloid Interface Sci 2018; 531:225-232. [DOI: 10.1016/j.jcis.2018.07.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/10/2018] [Accepted: 07/11/2018] [Indexed: 10/28/2022]
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11
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Napso S, Rein DM, Fu Z, Radulescu A, Cohen Y. Structural Analysis of Cellulose-Coated Oil-in-Water Emulsions Fabricated from Molecular Solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:8857-8865. [PMID: 29979601 DOI: 10.1021/acs.langmuir.8b01325] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Natural cellulose has been used as a coating to stabilize oil-in-water (o/w) emulsions by exploiting the amphiphilic character of the cellulose chains molecularly dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate. Its cellulose coating exhibits a continuous amorphous structure which differs significantly from the cellulose particle stabilization used in Pickering emulsions. The structure of these cellulose-coated o/w emulsion particles, in particular the cellulose coating shell characteristics (thickness, porosity, and composition), is studied by using a combination of direct imaging methods such as cryogenic electron microscopy and fluorescence microscopy with small-angle neutron scattering measurements. This work suggests a unique multicompartment structure of the emulsion particles: an oil core, surrounded by an inner shell composed of a porous cellulose gel, encapsulated by a dense outer cellulose shell, a few nanometers in thickness. The thickness of the inner cellulose shell varies significantly. The nanoscale emulsion droplets exhibit a thickness of 10 ± 3 nm, whereas the larger micron-sized droplets exhibit a thicker inner cellulose shell of 500-750 nm. It is also inferred that the cellulose shells contain water rather than oil.
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Affiliation(s)
- Sofia Napso
- Department of Chemical Engineering , Technion-Israel Institute of Technology , Technion City, Haifa 3200003 , Israel
| | - Dmitry M Rein
- Department of Chemical Engineering , Technion-Israel Institute of Technology , Technion City, Haifa 3200003 , Israel
| | - Zhendong Fu
- Jülich Center for Neutron Science, Forschungszentrum Jülich GmbH Outstation at MLZ , 85747 Garching , Germany
| | - Aurel Radulescu
- Jülich Center for Neutron Science, Forschungszentrum Jülich GmbH Outstation at MLZ , 85747 Garching , Germany
| | - Yachin Cohen
- Department of Chemical Engineering , Technion-Israel Institute of Technology , Technion City, Haifa 3200003 , Israel
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12
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Maestri CA, Bettotti P, Scarpa M. Fabrication of complex-shaped hydrogels by diffusion controlled gelation of nanocellulose crystallites. J Mater Chem B 2017; 5:8096-8104. [PMID: 32264648 DOI: 10.1039/c7tb01899a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this study we investigated the fabrication of small hydrogel objects by the coordination-driven assembly of supramolecular rod-like crystallites of nanocellulose, using ionotropic gelation as a methodological approach and Ca2+ as a gelling agent. We proved that the gelation process is diffusion-mediated and fitting the equations modelling this process to the profile of the Ca2+ front, a Ca2+ diffusion coefficient in the incipient hydrogel of (4.5 ± 1.1) × 10-6 cm2 s-1 was calculated. At the steady-state a spatially homogeneous distribution of Ca2+-crosslinked sites in the hydrogel network was observed. External ionotropic gelation produced beads, wires or disks, while core-shell capsules were obtained by inverse ionotropic gelation. We demonstrated that equilibrium and dynamics of the distribution of Ca2+ offer the opportunity to design precisely the size and shape of these small hydrogel objects. In particular, the core size and the shell thickness of the capsules can be tailored under kinetic controlled conditions. The proposed approach, with supramolecular structures of the natural source as assembling components and the water-in-water fabrication process, is fast, simple, and requires only sustainable chemistry and is easily implementable in automatic microfluidic platforms.
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Affiliation(s)
- C A Maestri
- Nanoscience Laboratory, Department of Physics, University of Trento, Via Sommarive 14, I-38123 Povo TN, Italy.
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13
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Alfassi G, Rein DM, Cohen Y. Enhanced hydrolysis of cellulose hydrogels by morphological modification. Bioprocess Biosyst Eng 2017; 40:1635-1641. [PMID: 28744568 DOI: 10.1007/s00449-017-1819-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/21/2017] [Indexed: 10/19/2022]
Abstract
Cellulose is one of the most abundant bio-renewable materials on earth, yet the potential of cellulosic bio-fuels is not fully exploited, primarily due to the high costs of conversion. Hydrogel particles of regenerated cellulose constitute a useful substrate for enzymatic hydrolysis, due to their porous and amorphous structure. This article describes the influence of several structural aspects of the cellulose hydrogel on its hydrolysis. The hydrogel density was shown to be directly proportional to the cellulose concentration in the initial solution, thus affecting its hydrolysis rate. Using high-resolution scanning electron microscopy, we show that the hydrogel particles in aqueous suspension exhibit a dense external surface layer and a more porous internal network. Elimination of the external surface layer accelerated the hydrolysis rate by up to sixfold and rendered the process nearly independent of cellulose concentration. These findings may be of practical relevance to saccharification processing costs, by reducing required solvent quantities and enzyme load.
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Affiliation(s)
- Gilad Alfassi
- Faculty of Chemical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel.
| | - Dmitry M Rein
- Faculty of Chemical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Yachin Cohen
- Faculty of Chemical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel
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14
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Lindman B, Medronho B, Alves L, Costa C, Edlund H, Norgren M. The relevance of structural features of cellulose and its interactions to dissolution, regeneration, gelation and plasticization phenomena. Phys Chem Chem Phys 2017. [DOI: 10.1039/c7cp02409f] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The interactions and structural properties of cellulose influence different phenomena.
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Affiliation(s)
- Björn Lindman
- FSCN
- Mid Sweden University
- SE-851 70 Sundsvall
- Sweden
- Physical Chemistry
| | - Bruno Medronho
- Faculty of Sciences and Technology (MeditBio)
- Ed. 8
- University of Algarve
- 8005-139 Faro
- Portugal
| | - Luis Alves
- CQC
- University of Coimbra
- Department of Chemistry
- 3004-535 Coimbra
- Portugal
| | | | - Håkan Edlund
- FSCN
- Mid Sweden University
- SE-851 70 Sundsvall
- Sweden
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