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Lazim NH, Hidzir NM, Shamsudin SA. Mechanical and thermal studies on modified 50/50 natural rubber latex/poly(styrene-block-isoprene-block-styrene) blend by gamma irradiation and comparison with sulphur and peroxide vulcanization methods. Radiat Phys Chem Oxf Engl 1993 2023. [DOI: 10.1016/j.radphyschem.2023.110857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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Rodrigues AP, Santos PMP, Veiga JP, Casimiro MH, Ferreira LM. Electron Beam Irradiation on the Production of a Si- and Zr-Based Hybrid Material: A Study by FTIR and WDXRF. MATERIALS (BASEL, SWITZERLAND) 2023; 16:489. [PMID: 36676223 PMCID: PMC9862691 DOI: 10.3390/ma16020489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/24/2022] [Accepted: 12/31/2022] [Indexed: 06/17/2023]
Abstract
Sol-gel production of hybrid materials has, to some extent, revolutionised materials' engineering and the way science and technology perceive the creation of new materials. Despite that, the method presents some limitations that are circumvented by radiation processing. Electron beam irradiation was used to promote synthesis of hybrid structures while using silanol-terminated PDMS, TEOS and TPOZ as precursors. Evaluation of the method's performance was executed by gel fraction determination, WDXRF and FTIR-ATR. Results showed that, although there is some pre-irradiation reactivity between precursors, radiolysis induces scission on multiple sites of precursor's structures, which induces hybrid network formation to a greater extent. Characterisation allowed determining electron beam irradiation to be effective in the creation of Si-O-Zr bonds, resulting in the production of a Class II hybrid material.
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Affiliation(s)
- Alexandra P. Rodrigues
- Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela, 2695-066 Loures, Portugal
- Departamento de Conservação e Restauro (DCR), Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
| | - Pedro M. P. Santos
- Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela, 2695-066 Loures, Portugal
| | - João Pedro Veiga
- Departamento de Conservação e Restauro (DCR), Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
- CENIMAT/i3N, Centro de Investigação de Materiais, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
| | - Maria Helena Casimiro
- Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela, 2695-066 Loures, Portugal
| | - Luís M. Ferreira
- Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela, 2695-066 Loures, Portugal
- Departamento de Engenharia e Ciências Nucleares (DECN), Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela, 2695-066 Loures, Portugal
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Manaila E, Craciun G, Ighigeanu D, Lungu IB, Dumitru Grivei MD, Stelescu MD. Degradation by Electron Beam Irradiation of Some Composites Based on Natural Rubber Reinforced with Mineral and Organic Fillers. Int J Mol Sci 2022; 23:ijms23136925. [PMID: 35805934 PMCID: PMC9266345 DOI: 10.3390/ijms23136925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 12/10/2022] Open
Abstract
Composites based on natural rubber reinforced with mineral (precipitated silica and chalk) and organic (sawdust and hemp) fillers in amount of 50 phr were obtained by peroxide cross-linking in the presence of trimethylolpropane trimethacrylate and irradiated by electron beam in the dose range of 150 and 450 kGy with the purpose of degradation. The composites mechanical characteristics, gel fraction, cross-linking degree, water uptake and weight loss in water and toluene were evaluated by specific analysis. The changes in structure and morphology were also studied by Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. Based on the results obtained in the structural analysis, possible mechanisms specific to degradation are proposed. The increasing of irradiation dose to 450 kGy produced larger agglomerated structures, cracks and micro voids on the surface, as a result of the degradation process. This is consistent with that the increasing of irradiation dose to 450 kGy leads to a decrease in crosslinking and gel fraction but also drastic changes in mechanical properties specific to the composites’ degradation processes. The irradiation of composites reinforced with organic fillers lead to the formation of specific degradation compounds of both natural rubber and cellulose (aldehydes, ketones, carboxylic acids, compounds with small macromolecules). In the case of the composites reinforced with mineral fillers the degradation can occur by the cleavage of hydrogen bonds formed between precipitated silica or chalk particles and polymeric matrix also.
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Affiliation(s)
- Elena Manaila
- Electron Accelerators Laboratory, National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, 077125 Magurele, Romania; (E.M.); (D.I.); (M.D.D.G.)
| | - Gabriela Craciun
- Electron Accelerators Laboratory, National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, 077125 Magurele, Romania; (E.M.); (D.I.); (M.D.D.G.)
- Correspondence: ; Tel.: +40-21-457-4346
| | - Daniel Ighigeanu
- Electron Accelerators Laboratory, National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, 077125 Magurele, Romania; (E.M.); (D.I.); (M.D.D.G.)
| | - Ion Bogdan Lungu
- Multipurpose Irradiation Facility Center—IRASM, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 30 Reactorului Street, 077125 Magurele, Romania;
| | - Marius Daniel Dumitru Grivei
- Electron Accelerators Laboratory, National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, 077125 Magurele, Romania; (E.M.); (D.I.); (M.D.D.G.)
| | - Maria Daniela Stelescu
- Leather and Footwear Research Institute, National R&D Institute for Textile and Leather, 93 Ion Minulescu Street, 031215 Bucharest, Romania;
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Basik AA, Trakunjae C, Yeo TC, Sudesh K. Streptomyces sp. AC04842: Genomic Insights and Functional Expression of Its Latex Clearing Protein Genes (lcp1 and lcp2) When Cultivated With Natural and Vulcanized Rubber as the Sole Carbon Source. Front Microbiol 2022; 13:854427. [PMID: 35586859 PMCID: PMC9108482 DOI: 10.3389/fmicb.2022.854427] [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: 01/13/2022] [Accepted: 03/11/2022] [Indexed: 11/21/2022] Open
Abstract
Rubber-degrading Actinobacteria have been discovered and investigated since 1985. Only recently, through the advancement of genomic sequencing and molecular techniques, genes and pathways involved in rubber degradation are being revealed; however, the complete degradation pathway remains unknown. Streptomyces sp. AC04842 (JCM 34241) was discovered by screening at a Culture Collection Centre in Sarawak for Actinomycetes forming a clear zone on natural rubber latex agar. Streptomyces is a dominant and well-studied soil bacterium playing an important role in soil ecology including carbon recycling and biodegradation. Streptomyces sp. AC04842 draft genome revealed the presence of 2 putative latex clearing protein (lcp) genes on its chromosome and is closely related to Streptomyces cellulosae. Under the Streptomyces genus, there are a total of 64 putative lcp genes deposited in the GenBank and UniProt database. Only 1 lcp gene from Streptomyces sp. K30 has been characterized. Unlike Streptomyces sp. K30 which contained 1 lcp gene on its chromosome, Streptomyces sp. AC04842 contained 2 lcp genes on its chromosome. Streptomyces sp. AC04842 lcp1 and lcp2 amino acid sequences showed 46.13 and 69.11%, respectively, similarity to lcp sequences of Streptomyces sp. K30. Most rubber degrading strains were known to harbor only 1 lcp gene, and only recently, 2–3 lcp homologs have been reported. Several studies have shown that lcp-homolog expression increased in the presence of rubber. To study the expression of lcp1 and lcp2 genes for Streptomyces sp. AC04842, the strain was incubated in different types of rubber as the sole carbon source. In general, the lcp1 gene was highly expressed, while the lcp2 gene expression was upregulated in the presence of vulcanized rubber. Mixtures of natural and vulcanized rubber did not further increase the expression of both lcp genes compared with the presence of a specific rubber type. In this study, we paved the way to the exploration of lcp homologs and their function in degrading different types of rubber.
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Affiliation(s)
- Ann Anni Basik
- Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Gelugor, Malaysia
- Sarawak Biodiversity Centre, Kuching, Malaysia
| | - Chanaporn Trakunjae
- Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Gelugor, Malaysia
- Kasetsart Agricultural and Agro-Industrial Product Improvement Institute (KAPI), Kasetsart University, Bangkok, Thailand
| | | | - Kumar Sudesh
- Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Gelugor, Malaysia
- *Correspondence: Kumar Sudesh,
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马 欣, 朱 晓, 李 静, 李 德, 李 和, 谭 建. [Effect of a novel radio-frequency atmospheric-pressure glow discharge plasma jet treatment on crosslinking of dentin collagen]. BEIJING DA XUE XUE BAO. YI XUE BAN = JOURNAL OF PEKING UNIVERSITY. HEALTH SCIENCES 2022; 54:83-88. [PMID: 35165472 PMCID: PMC8860638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Indexed: 11/06/2023]
Abstract
OBJECTIVE To investigate the effect of a noval radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma jet on crosslinking of dentin collagen. METHODS (1) Twenty intact third molars were collected. The middle dentin discs were prepared for each tooth by low-speed water-cooled Isomet saw, and then immersed in 10% (mass fraction) H3PO4 solution for 16 h to obtain fully demine-ralized dentin collagen. The twenty dentin discs were then randomly divided into five groups. The control group was untreated while the four experimental groups were treated by plasma jet with gas temperature of 4 ℃ for different times (20 s, 30 s, 40 s, and 50 s). The structure and crosslinking degree of dentin collagen were characterized by attenuated total reflection-Fourier transform infrared spectroscopy. The surface morphology of demineralized dentin was observed by scanning electron microscope, and the microstructure was observed by transmission electron microscope. (2) Fourty non-caries third molars were collected to prepare 5 g fine dentin powder, then completely demineralized with 10% H3PO4 solution. The control group was untreated, while the four experimental groups were treated by plasma jet for 20 s, 30 s, 40 s and 50 s. The crosslinking degree of each group was determined by ninhydrin colorimetric method. (3) Forty intact third molars were collected to obtain dentin strips. Only two central symmetrical dentin strips (nasty 80) were taken from each tooth and immersed in 10% H3PO4 solution for 16 h to obtain fully demineralized dentin collagen. Eighty dentine collagen fiber strips were randomly divided into five groups. The control group was untreated and the axial surfaces of dentin collagen fiber strips in the expe-rimental groups were treated with the plasma jet for 20 s, 30 s, 40 s and 50 s. The ultimate tensile strength of dentin was measured by universal mechanical machine. RESULTS (1) The surface morphology of demineralized dentin observed by scanning electron microscope showed that the network structure of collagen fibers on the surface of demineralized dentin treated with the plasma jet for 20 s, 30 s and 40 s could maintain the uncollapsed three-dimensional structure, and part of the microstructure was destroyed after plasma jet treated for 50 s. After being treated by plasma jet for 20 s, 30 s and 40 s, the three-dimensional structure was uncollapsed, and the typical periodic transverse pattern of natural type Ⅰ collagen fiber could be seen. The results of infrared spectra showed that the secondary conformation of dentin collagen fibers was the same as that of the control group after being treated with the plasma jet, and the intensity of amide band was significantly increased after being treated for 30 s and 40 s. (2) The results of ninhydrin crosslinking test showed that the crosslinking ratio of dentin collagen treated by plasma jet for 30 s and 40 s was the highest, and the difference was statistically significant (P < 0.05). (3) The results of dentin ultimate tensile strength showed that the control group was (1.67±0.24) MPa, and the plasma jet treated 20 s, 30 s, 40 s and 50 s groups were (4.21±0.15) MPa, (7.06±0.30) MPa, (7.32±0.27) MPa, and (6.87±0.17) MPa, which were significantly different from that of the control group (P < 0.05). CONCLUSION The novel RF-APGD plasma jet treatment can promote the crosslinking degree of demineralized dentin collagen and improve their ultimate tensile strength.
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Affiliation(s)
- 欣蓉 马
- 北京大学口腔医学院·口腔医院修复科,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,北京 100081Department of Prothodontics, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing 100081, China
| | - 晓鸣 朱
- 北京大学口腔医学院·口腔医院第二门诊部,北京 100101Second Clinical Division, Peking University School and Hospital of Stomatology, Beijing 100101, China
| | - 静 李
- 清华大学工程物理系,北京 100084Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - 德利 李
- 北京大学口腔医学院·口腔医院第二门诊部,北京 100101Second Clinical Division, Peking University School and Hospital of Stomatology, Beijing 100101, China
| | - 和平 李
- 清华大学工程物理系,北京 100084Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - 建国 谭
- 北京大学口腔医学院·口腔医院修复科,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,北京 100081Department of Prothodontics, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing 100081, China
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6
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马 欣, 朱 晓, 李 静, 李 德, 李 和, 谭 建. [Effect of a novel radio-frequency atmospheric-pressure glow discharge plasma jet treatment on crosslinking of dentin collagen]. BEIJING DA XUE XUE BAO. YI XUE BAN = JOURNAL OF PEKING UNIVERSITY. HEALTH SCIENCES 2022; 54:83-88. [PMID: 35165472 PMCID: PMC8860638 DOI: 10.19723/j.issn.1671-167x.2022.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Indexed: 06/14/2023]
Abstract
OBJECTIVE To investigate the effect of a noval radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma jet on crosslinking of dentin collagen. METHODS (1) Twenty intact third molars were collected. The middle dentin discs were prepared for each tooth by low-speed water-cooled Isomet saw, and then immersed in 10% (mass fraction) H3PO4 solution for 16 h to obtain fully demine-ralized dentin collagen. The twenty dentin discs were then randomly divided into five groups. The control group was untreated while the four experimental groups were treated by plasma jet with gas temperature of 4 ℃ for different times (20 s, 30 s, 40 s, and 50 s). The structure and crosslinking degree of dentin collagen were characterized by attenuated total reflection-Fourier transform infrared spectroscopy. The surface morphology of demineralized dentin was observed by scanning electron microscope, and the microstructure was observed by transmission electron microscope. (2) Fourty non-caries third molars were collected to prepare 5 g fine dentin powder, then completely demineralized with 10% H3PO4 solution. The control group was untreated, while the four experimental groups were treated by plasma jet for 20 s, 30 s, 40 s and 50 s. The crosslinking degree of each group was determined by ninhydrin colorimetric method. (3) Forty intact third molars were collected to obtain dentin strips. Only two central symmetrical dentin strips (nasty 80) were taken from each tooth and immersed in 10% H3PO4 solution for 16 h to obtain fully demineralized dentin collagen. Eighty dentine collagen fiber strips were randomly divided into five groups. The control group was untreated and the axial surfaces of dentin collagen fiber strips in the expe-rimental groups were treated with the plasma jet for 20 s, 30 s, 40 s and 50 s. The ultimate tensile strength of dentin was measured by universal mechanical machine. RESULTS (1) The surface morphology of demineralized dentin observed by scanning electron microscope showed that the network structure of collagen fibers on the surface of demineralized dentin treated with the plasma jet for 20 s, 30 s and 40 s could maintain the uncollapsed three-dimensional structure, and part of the microstructure was destroyed after plasma jet treated for 50 s. After being treated by plasma jet for 20 s, 30 s and 40 s, the three-dimensional structure was uncollapsed, and the typical periodic transverse pattern of natural type Ⅰ collagen fiber could be seen. The results of infrared spectra showed that the secondary conformation of dentin collagen fibers was the same as that of the control group after being treated with the plasma jet, and the intensity of amide band was significantly increased after being treated for 30 s and 40 s. (2) The results of ninhydrin crosslinking test showed that the crosslinking ratio of dentin collagen treated by plasma jet for 30 s and 40 s was the highest, and the difference was statistically significant (P < 0.05). (3) The results of dentin ultimate tensile strength showed that the control group was (1.67±0.24) MPa, and the plasma jet treated 20 s, 30 s, 40 s and 50 s groups were (4.21±0.15) MPa, (7.06±0.30) MPa, (7.32±0.27) MPa, and (6.87±0.17) MPa, which were significantly different from that of the control group (P < 0.05). CONCLUSION The novel RF-APGD plasma jet treatment can promote the crosslinking degree of demineralized dentin collagen and improve their ultimate tensile strength.
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Affiliation(s)
- 欣蓉 马
- 北京大学口腔医学院·口腔医院修复科,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,北京 100081Department of Prothodontics, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing 100081, China
| | - 晓鸣 朱
- 北京大学口腔医学院·口腔医院第二门诊部,北京 100101Second Clinical Division, Peking University School and Hospital of Stomatology, Beijing 100101, China
| | - 静 李
- 清华大学工程物理系,北京 100084Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - 德利 李
- 北京大学口腔医学院·口腔医院第二门诊部,北京 100101Second Clinical Division, Peking University School and Hospital of Stomatology, Beijing 100101, China
| | - 和平 李
- 清华大学工程物理系,北京 100084Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - 建国 谭
- 北京大学口腔医学院·口腔医院修复科,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,北京 100081Department of Prothodontics, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing 100081, China
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Lazim NH, Hidzir NM, Hamzah NS, Mikihito T, Shamsudin SA. The effects of the cross‐linking mechanism of low doses of gamma irradiation on the mechanical, thermal, and viscoelastic properties of the natural rubber latex/poly(styrene‐
block
‐isoprene‐
block
‐styrene) block copolymer blend. POLYM ENG SCI 2022. [DOI: 10.1002/pen.25843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Nurul Hakimah Lazim
- Department of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia (UKM) Bangi Selangor Malaysia
| | - Norsyahidah Mohd Hidzir
- Department of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia (UKM) Bangi Selangor Malaysia
- Nuclear Technology Research Centre, Faculty of Science and Technology Universiti Kebangsaan Malaysia (UKM) Bangi Selangor Malaysia
| | - Naim Syauqi Hamzah
- Reactor Nuclear & Physics Section, Reactor Technology Center Malaysian Nuclear Agency Bangi Selangor Malaysia
| | - Takenaka Mikihito
- Institute for Chemical Research Kyoto University Kyoto Gokasho, Uji Japan
| | - Siti Aisyah Shamsudin
- Department of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia (UKM) Bangi Selangor Malaysia
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Basik AA, Nanthini J, Yeo TC, Sudesh K. Rubber Degrading Strains: Microtetraspora and Dactylosporangium. Polymers (Basel) 2021; 13:3524. [PMID: 34685283 PMCID: PMC8538451 DOI: 10.3390/polym13203524] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/03/2021] [Accepted: 10/06/2021] [Indexed: 11/23/2022] Open
Abstract
Rubber composed of highly unsaturated hydrocarbons, modified through addition of chemicals and vulcanization are widely used to date. However, the usage of rubber, faces many obstacles. These elastomeric materials are difficult to be re-used and recovered, leading to high post-consumer waste and vast environmental problems. Tyres, the major rubber waste source can take up to 80 years to naturally degrade. Experiments show that the latex clearing proteins (Lcp) found in Actinobacteria were reportedly critical for the initial oxidative cleavage of poly(cis-1,4-isoprene), the major polymeric unit of rubber. Although, more than 100 rubber degrading strains have been reported, only 8 Lcp proteins isolated from Nocardia (3), Gordonia (2), Streptomyces (1), Rhodococcus (1), and Solimonas (1) have been purified and biochemically characterized. Previous studies on rubber degrading strains and Lcp enzymes, implied that they are distinct. Following this, we aim to discover additional rubber degrading strains by randomly screening 940 Actinobacterial strains isolated from various locations in Sarawak on natural rubber (NR) latex agar. A total of 18 strains from 5 genera produced clearing zones on NR latex agar, and genes encoding Lcp were identified. We report here lcp genes from Microtetraspora sp. AC03309 (lcp1 and lcp2) and Dactylosporangium sp. AC04546 (lcp1, lcp2, lcp3), together with the predicted genes related to rubber degradation. In silico analysis suggested that Microtetraspora sp. AC03309 is a distinct species closely related to Microtetraspora glauca while Dactylosporangium sp. AC04546 is a species closely related to Dactylosporangium sucinum. Genome-based characterization allowed the establishment of the strains taxonomic position and provided insights into their metabolic potential especially in biodegradation of rubber. Morphological changes and the spectrophotometric detection of aldehyde and keto groups indicated the degradation of the original material in rubber samples incubated with the strains. This confirms the strains' ability to utilize different rubber materials (fresh latex, NR product and vulcanized rubber) as the sole carbon source. Both strains exhibited different levels of biodegradation ability. Findings on tyre utilization capability by Dactylosporangium sp. AC04546 is of interest. The final aim is to find sustainable rubber treatment methods to treat rubber wastes.
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Affiliation(s)
- Ann Anni Basik
- Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, George Town 11800, Malaysia;
- Sarawak Biodiversity Centre, Km. 20 Jalan Borneo Heights, Kuching 93250, Malaysia;
| | - Jayaram Nanthini
- Faculty of Arts & Science, School of Science & Psychology, International University of Malaya-Wales, Kuala Lumpur 50480, Malaysia;
| | - Tiong Chia Yeo
- Sarawak Biodiversity Centre, Km. 20 Jalan Borneo Heights, Kuching 93250, Malaysia;
| | - Kumar Sudesh
- Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, George Town 11800, Malaysia;
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Manaila E, Craciun G, Ighigeanu D, Stelescu MD. Water Absorption Kinetics in Composites Degraded by the Radiation Technique. MATERIALS 2021; 14:ma14164659. [PMID: 34443179 PMCID: PMC8399285 DOI: 10.3390/ma14164659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/09/2021] [Accepted: 08/12/2021] [Indexed: 11/16/2022]
Abstract
Rubber-based wastes represent challenges facing the global community. Human health protection and preservation of environmental quality are strong reasons to find more efficient methods to induce degradation of latex/rubber products in order to replace devulcanization, incineration, or simply storage, and electron beam irradiation is a promising method that can be can be taken into account. Polymeric composites based on natural rubber and plasticized starch in amounts of 10 to 50 phr, obtained by benzoyl peroxide cross-linking, were subjected to 5.5 MeV electron beam irradiation in order to induce degradation, in the dose range of 150 to 450 kGy. A qualitative study was conducted on the kinetics of water absorption in these composites in order to appreciate their degradation degree. The percentages of equilibrium sorption and mass loss after equilibrium sorption were found to be dependent on irradiation dose and amount of plasticized starch. The mechanism of water transport in composites was studied not only through the specific absorption and diffusion parameters but also by the evaluation of the diffusion, intrinsic diffusion, permeation, and absorption coefficients.
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Affiliation(s)
- Elena Manaila
- Electron Accelerators Laboratory, National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor St., 077125 Magurele, Romania; (E.M.); (D.I.)
| | - Gabriela Craciun
- Electron Accelerators Laboratory, National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor St., 077125 Magurele, Romania; (E.M.); (D.I.)
- Correspondence: ; Tel.: +40-04-021-457-4346
| | - Daniel Ighigeanu
- Electron Accelerators Laboratory, National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor St., 077125 Magurele, Romania; (E.M.); (D.I.)
| | - Maria Daniela Stelescu
- National R&D Institute for Textile and Leather—Leather and Footwear Research Institute, 93 Ion Minulescu St, 031215 Bucharest, Romania;
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Electron Beam Irradiation: A Method for Degradation of Composites Based on Natural Rubber and Plasticized Starch. Polymers (Basel) 2021; 13:polym13121950. [PMID: 34208234 PMCID: PMC8230875 DOI: 10.3390/polym13121950] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/28/2021] [Accepted: 06/08/2021] [Indexed: 11/18/2022] Open
Abstract
Polymeric composites based on natural rubber (NR) and plasticized starch (PS) obtained by peroxide cross-linking have been subjected to electron beam irradiation in order to investigate their degradation. The amount of PS ranged from 10 to 50 phr and the irradiation dose from 150 to 450 kGy. Irradiation was performed in atmospheric conditions using a linear electron accelerator of 5.5 MeV. Changes in chemical, physical, structural, and morphological properties of composites were correlated with variables, such as PS loading and irradiation dose. Thus, mechanical properties, gel fraction, cross-linking degree, water uptake, weight loss in toluene/water were compared with those obtained before irradiation. The changes in structure and morphology were studied by Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. Both PS loading and irradiation dose were found to be responsible for the degradation installing. Moreover, it has been shown that at the dose of 450 kGy, chain scission is dominant over cross-linking.
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11
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Braşoveanu M, Nemţanu MR. Temperature Profile in Starch during Irradiation. Indirect Effects in Starch by Radiation-Induced Heating. MATERIALS (BASEL, SWITZERLAND) 2021; 14:3061. [PMID: 34205181 PMCID: PMC8199976 DOI: 10.3390/ma14113061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/31/2021] [Accepted: 05/31/2021] [Indexed: 12/24/2022]
Abstract
Present research deals with exposure of granular starch to the accelerated electron of 5.5 MeV energy in order to examine: (i) the temperature evolution in starch within an irradiation process and (ii) the indirect effects generated in starch by radiation-induced heating. The temperature evolution in potato and corn starches within the irradiation process was investigated by placing two different sensors inside each starch batch and recording the temperature simultaneously. Each starch batch was sampled into distinct location sectors of different absorbed radiation levels. The output effects in each sample were analyzed through physicochemical properties such as moisture content, acidity and color attributes. The outcomes showed that a starch temperature profile had different major stages: (i) heating during irradiation, (ii) post-irradiation heating, up to the maximum temperature is reached, and (iii) cooling to the room temperature. A material constant with signification of a relaxation time was identified by modeling the temperature evolution. Changes of the investigated properties were induced both by irradiation and radiation-induced heating, depending on the starch type and the batch sectors. Changes in the irradiated batch sectors were explained by irradiation and radiation-induced heating whereas changes in the sector of non-irradiated starch were attributed only to the heating.
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Affiliation(s)
| | - Monica R. Nemţanu
- Electron Accelerators Laboratory, National Institute for Lasers, Plasma and Radiation Physics 409 Atomiştilor St., P.O. Box MG-36, 077125 Bucharest-Măgurele, Romania;
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12
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Effects of Coagent Functionalities on Properties of Ultrafine Fully Vulcanized Powdered Natural Rubber Prepared as Toughening Filler in Rigid PVC. Polymers (Basel) 2021; 13:polym13020289. [PMID: 33477520 PMCID: PMC7831084 DOI: 10.3390/polym13020289] [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: 12/03/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 11/16/2022] Open
Abstract
Ultrafine fully vulcanized powdered natural rubber (UFPNR) has a promising application as a renewable toughening modifier in polymer matrices. In this work, the effects of acrylate coagents, which had different amounts of functional groups, on properties of UFPNR produced by radiation vulcanization and spray-drying was systematically investigated for the first time. Dipropylene glycol diacrylate (DPGDA), trimethylol propane trimethaacrylate (TMPTMA), and ditrimethylol propane tetraacrylate (DTMPTA) were used as coagents with two, three, and four acrylate groups, respectively. The radiation in the range of 250 to 400 kGy and coagent contents of up to 11 phr were used in the production process. Physical, chemical, and thermal properties of the UFPNR were characterized by swelling analysis, scanning electron microscopy, infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The properties of UFPNR produced by using different type and content of coagents were compared and discussed. The results revealed that UFPNR with the smallest particle size of 3.6 ± 1.1 μm and the highest thermal stability (Td5 = 349 °C) could be obtained by using DTMPTA, which had the highest amount of functional group. It was proposed that the coagent with the greater number of acrylate groups enhanced the crosslinking of natural rubber as it had more reactive groups. Finally, an application of UFPNR as a toughening filler in rigid PVC was demonstrated with 34% improvement of impact strength.
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13
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Román AJ, Travis JZ, Ávila JCM, Osswald TA. Influence of plantation climate and storage time on thermal and viscoelastic properties of natural rubber. AIMS BIOENGINEERING 2021. [DOI: 10.3934/bioeng.2021010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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14
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Water Absorption Kinetics in Natural Rubber Composites Reinforced with Natural Fibers Processed by Electron Beam Irradiation. Polymers (Basel) 2020; 12:polym12112437. [PMID: 33105756 PMCID: PMC7690617 DOI: 10.3390/polym12112437] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/15/2020] [Accepted: 10/21/2020] [Indexed: 11/25/2022] Open
Abstract
Natural rubber composites reinforced with hemp, flax, and wood sawdust were obtained by irradiation at room temperature with an electron beam of 5.5 MeV in order to meet the actual need for new materials that are environmentally friendly and safe for human health. The natural fibers loading was between 5 and 20 phr and the processing doses were between 75 and 600 kGy. The kinetics of water absorption in these materials were studied. The water diffusion was analyzed through Fick’s law. The water absorption parameters (Qt and Qeq), diffusion parameters (k and n), diffusion coefficient (D), intrinsic diffusion coefficient (D*), sorption coefficient (S), and permeation coefficient (P) have depended on the fiber nature, amount used in blends, and irradiation dose. The obtained results showed that not in the case of each type of fiber used, the water absorption could be correlated with the specific cellulose and hemicellulose content, due to the changes induced by the electron beam.
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15
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Craciun G, Manaila E, Ighigeanu D, Stelescu MD. A Method to Improve the Characteristics of EPDM Rubber Based Eco-Composites with Electron Beam. Polymers (Basel) 2020; 12:polym12010215. [PMID: 31952265 PMCID: PMC7023520 DOI: 10.3390/polym12010215] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 12/05/2022] Open
Abstract
A natural fiber reinforced composite, belonging to the class of eco composites, based on ethylene-propylene-terpolymer rubber (EPDM) and wood wastes were obtained by electron beam irradiation at 75, 150, 300, and 600 kGy in atmospheric conditions and at room temperature using a linear accelerator of 5.5 MeV. The sawdust (S), in amounts of 5 and 15 phr, respectively, was used to act as a natural filler for the improvement of physical and chemical characteristics. The cross-linking effects were evaluated through sol-gel analysis, mechanical tests, and Fourier Transform Infrared FTIR spectroscopy comparatively with the classic method with dibenzoyl peroxide (P) applied on the same types of samples at high temperature. Gel fraction exhibits values over 98% but, in the case of P cross-linking, is necessary to add more sawdust (15 phr) to obtain the same results as in the case of electron beam (EB) cross-linking (5 phr/300 kGy). Even if the EB cross-linking and sawdust addition have a reinforcement effect on EPDM rubber, the medium irradiation dose of 300 kGy looks to be a limit to which or from which the properties of the composite are improved or deteriorated. The absorption behavior of the eco-composites was studied through water uptake tests.
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Affiliation(s)
- Gabriela Craciun
- National Institute for Laser, Plasma and Radiation Physics, # 409 Atomistilor St., 077125 Magurele, Romania; (G.C.); (D.I.)
| | - Elena Manaila
- National Institute for Laser, Plasma and Radiation Physics, # 409 Atomistilor St., 077125 Magurele, Romania; (G.C.); (D.I.)
- Correspondence:
| | - Daniel Ighigeanu
- National Institute for Laser, Plasma and Radiation Physics, # 409 Atomistilor St., 077125 Magurele, Romania; (G.C.); (D.I.)
| | - Maria Daniela Stelescu
- National R&D Institute for Textile and Leather—Leather and Footwear Research Institute, # 93 Ion Minulescu St., 031215 Bucharest, Romania;
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16
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ZHU XM, ZHOU JF, GUO H, ZHANG XF, LIU XQ, LI HP, TAN JG. Effects of a modified cold atmospheric plasma jet treatment on resin-dentin bonding. Dent Mater J 2018; 37:798-804. [DOI: 10.4012/dmj.2017-314] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Xiao-Ming ZHU
- Department of Prosthodontics, Peking University School and Hospital of Stomatology
| | - Jian-Feng ZHOU
- Department of Prosthodontics, Peking University School and Hospital of Stomatology
| | - Heng GUO
- Department of Engineering Physics, Tsinghua University
| | | | - Xiao-Qiang LIU
- Department of Prosthodontics, Peking University School and Hospital of Stomatology
| | - He-Ping LI
- Department of Engineering Physics, Tsinghua University
| | - Jian-Guo TAN
- Department of Prosthodontics, Peking University School and Hospital of Stomatology
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17
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Manaila E, Stelescu MD, Craciun G. Degradation Studies Realized on Natural Rubber and Plasticized Potato Starch Based Eco-Composites Obtained by Peroxide Cross-Linking. Int J Mol Sci 2018; 19:ijms19102862. [PMID: 30241399 PMCID: PMC6212896 DOI: 10.3390/ijms19102862] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/14/2018] [Accepted: 09/18/2018] [Indexed: 11/16/2022] Open
Abstract
The obtaining and characterization of some environmental-friendly composites that are based on natural rubber and plasticized starch, as filler, are presented. These were obtained by peroxide cross-linking in the presence of a polyfunctional monomer used here as cross-linking co-agent, trimethylolpropane trimethacrylate. The influence of plasticized starch amount on the composites physical and mechanical characteristics, gel fraction and cross-link density, water uptake, structure and morphology before and after accelerated (thermal) degradation, and natural (for one year in temperate climate) ageing, was studied. Differences of two orders of magnitude between the degradation/aging methods were registered in the case of some mechanical characteristics, by increasing the plasticized starch amount. The cross-link density, water uptake and mass loss were also significant affected by the plasticized starch amount increasing and exposing for one year to natural ageing in temperate climate. Based on the results of Fourier Transform Infrared Spectroscopy (FTIR) and cross-link density measurements, reaction mechanisms attributed to degradation induced by accelerated and natural ageing were done. SEM micrographs have confirmed in addition that by incorporating a quantity of hydrophilic starch amount over 20 phr and by exposing the composites to natural ageing, and then degradability can be enhanced by comparing with thermal degradation.
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Affiliation(s)
- Elena Manaila
- Electron Accelerators Laboratory, National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, 077125 Magurele, Romania.
| | - Maria Daniela Stelescu
- National R&D Institute for Textile and Leather-Leather and Footwear Research Institute, 93 Ion Minulescu Street, 031215 Bucharest, Romania.
| | - Gabriela Craciun
- Electron Accelerators Laboratory, National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, 077125 Magurele, Romania.
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18
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Calina I, Demeter M, Vancea C, Scarisoreanu A, Meltzer V. E-beam radiation synthesis of xanthan-gum/carboxymethylcellulose superabsorbent hydrogels with incorporated graphene oxide. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2018. [DOI: 10.1080/10601325.2018.1424552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ion Calina
- National Institute for Laser, Plasma and Radiation Physics, Accelerators Laboratory, 409 Atomistilor, Magurele, Romania
- Faculty of Physics, University of Bucharest, 405 Atomistilor, Magurele, Romania
| | - Maria Demeter
- National Institute for Laser, Plasma and Radiation Physics, Accelerators Laboratory, 409 Atomistilor, Magurele, Romania
- Faculty of Chemistry, University of Bucharest, Bucharest, Romania
| | - Catalin Vancea
- National Institute for Laser, Plasma and Radiation Physics, Accelerators Laboratory, 409 Atomistilor, Magurele, Romania
- Faculty of Physics, University of Bucharest, 405 Atomistilor, Magurele, Romania
| | - Anca Scarisoreanu
- National Institute for Laser, Plasma and Radiation Physics, Accelerators Laboratory, 409 Atomistilor, Magurele, Romania
| | - Viorica Meltzer
- Faculty of Chemistry, University of Bucharest, Bucharest, Romania
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