就地反应法制备天然橡胶/二氧化硅复合材料

在天然胶乳与Na2SiO3水溶液的混合体系中滴加盐酸,就地生成SiO2粒子,并与天然橡胶(NR)同时发生凝聚共沉,获得了NR/SiO2透明复合材料。用扫描电子显微镜和分光光度计分析了材料的结构,测定了硫化胶的力学性能。结果表明,SiO2的粒径随混合体系中Na2SiO3投料量的提高而增大,并均匀分布于NR基体中;当复合材料中SiO2用量为25～54份时,SiO2的粒径为100～200nm;在SiO2用量适宜的条件下,复合材料硫化胶具有良好的力学性能;硫化胶片具有一定的透明性,在波长为600～800nm时,其透光率为50%～72%。

Preparation of natural rubber/silica composite by in situ reaction

The natural rubber (NR)/silica transparent composite was prepared by in situ reaction, which was obtained by titration of Na_2SiO_3 and natural rubber latex mixture system with HCl solution. The process happened simultaneously for generation of SiO_2 particles by in situ reaction and formation of NR/silica composite by coacervation-coprecipitation of the mixture system. The structure and properties of NR/silica composite vulcanizate were investigated by SEM and spectrophotometer. It was shown that the SiO_2 particle size, which was distributed homogeneously in NR matrix, increased with the increase of Na_2SiO_3 charge in the mixture system and was 100~200 nm when SiO_2 content was 25~54 phr in the composite. The composite vulcanizate had good mechanical properties when SiO_2 content was suitable. The composite vulcanizate sheet had a considerable transparent appearance and the light transmissivity was 50%~72% in the wavelength range from 600 nm to 80 nm .