Effect of dilution concentration of fresh latex on composition and properties of natural rubber coagulated by enzymes
Natural rubber samples were prepared using alkaline proteinase coagulation of fresh latex with dilution concentrations of 34%,25%,20%and 17%to investigate the effect of dilution concentration of fresh latex on composition and properties of natural rubber coagulated by enzymes.The natural rubber was characterised using instruments such as rotorless rheometer,rubber processing analysers and tensile testing machines,respectively.The results showed that as the dilution concentration of fresh latex decreased,the plasticity initial value(P0)of natural raw rubber firstly increased and then decreased,while the plasticity retention rate(PRI)was the opposite;its nitrogen content,acetone soluble content and molecular chain branching gradually decreased;the scorch time(t10)and positive vulcanisation time(t90)of the com-pound rubber increased by 19.05%and 5.62%respectively,while the torque difference gradually de-creased;the tensile strength,tear strength and constant elongation stress of the vulcanised rubber slightly decreased,while the elongation at tear slightly increased.
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