改性累托石粉体的制备及其填充橡胶复合材料的结构与性能

利用喷雾干燥法制备了硅烷偶联剂KH550改性的累托石粉体, 考察了喷嘴进口温度对制备的累托石粉体表面性质、结构及形貌的影响。将累托石粉体分别加入到丁苯橡胶(SBR)、天然橡胶(NR)和丁腈橡胶(NBR)中, 通过熔融共混法制备了改性累托石/橡胶复合材料, 研究了累托石在橡胶基体中的分散状态及其对基体的增强效果。结果表明: 随着进气温度的提高, 与累托石复合的KH550的量也随之增加; KH550分子插层进入累托石层间, 阻碍了片层的再聚集, 片层堆砌更加无序蓬松; 改性累托石在SBR中出现了局部团聚现象, 在NBR中分散较均匀, 而在NR中分散状态最好; 与相应的纯橡胶相比, 改性累托石填充的SBR和NBR基复合材料的各项力学性能均有所提高, 而其填充的NR基复合材料的定伸应力提高, 拉伸强度和撕裂强度基本不变, 断裂伸长率有所下降。

Preparation of modified rectorite powder and structure and properties of modified rectorite powder/rubber composites

The aminosilane coupling agent KH550 modified rectorite(REC) powder was prepared by the spray drying method, and the influence of the inlet air temperature on the surface characteristics, structure and morphology of the modified REC powder was examined. The modified REC/ styrene-butadiene rubber(SBR), REC/natural rubber(NR) and REC/nitrile-butadiene rubber(NBR) composites were prepared by the melt blending method. The dispersion of the modified REC powder in the rubber matrixes and its reinforcement effects on the matrixes were also investigated. The results show that raising the inlet air temperature increases the amount of KH550 in the modified REC, and then promotes the modification of REC. KH550 molecules intercalate into the intergallery of REC, resulting in smaller aggregates and more loosely packed structures in the modified REC powders. No intercalation of rubber macromolecules into the interlayer of REC occurs in all three modified REC/rubber composites. The modified REC layers aggregate locally in SBR, they are uniformly dispersed in NBR, and exhibit the best dispersion state in NR. Compared with the corresponding the pure rubbers, the mechanical properties of the modified REC powder filled SBR and NBR composites are comprehensively improved, regarding the modified REC/NR composite, the stress is enhanced, the tensile and tear strengths are kept unchanged, and the elongation at break is decreased compared with the pure NR.