1995 Fiscal Year Final Research Report Summary
Deproteinization of Natural Rubber Latex and Synthesis of Highly Purified Natural Rubber Latex
| Project/Area Number |
06651018
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
高分子合成
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
TANAKA Yasuyuki Tokyo University of Agriculture and Technology, Faculty of Technology, Professor, 工学部, 教授 (80015114)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAHARA Seiichi Tokyo University of Agriculture and Technology, Faculty of Technology, Assistant, 工学部, 助手 (00242248)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Natural Rubber / Latex / Proteolytic Enzyme / Processability / Water Repellency / oxidative degradation / Liquid Natural Rubber |
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| Research Abstract |
Purification of natural rubber was curried out by deproteinization and transesterification. Nitrogen content in commercial natural rubber latex was reduced from 0.3% to 0.01 (w/w) by treatment with proteolytic enzyme in the presence of surfactants. The residual nitrogenous compound was presumed to be oligo peptide linked to rubber. Deproteinization resulted in a significant decrease in gel content and a slight decrease in molecular weight. The physical properties of vulcanizates were unchanged by deproteinization, although a large improvement for water adsoptivity and electric resistance were observed. Transesterification of rubber decomposed the branch-points to form linear rubber molecules. The green strength of rubber decreased significantly after transesterification, while not changed by deproteinization.
The deproteinization process was accompanied with the reduction of naturally occurring antioxidants. The deproteinized rubber was easily decomposed to low molecular weight liquid rubber by air oxidation in the presence of catalyst such as cobalt dichloride in toluene solution or potassium persulfate in latex. Both terminal group of these liquid rubbers were presumed to be carbonyl groups.
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