三元乙丙橡胶/蒙脱土纳米复合材料制备中硫化体系的比较

A COMPARISON BETWEEN VULCANIZATION AGENTS FOR PREPARATION OF EPDM/MONTMORILLONITE NANOCOMPOSITES

采用了熔融插层和两种硫化体系硫磺 促进剂和过氧化物体系制备了三元乙丙橡胶 蒙脱土纳米复合材料 ,并将这两种体系形成的纳米复合材料进行了形态、力学性能和光学性能的比较 ,同时采用Flory Rehner方程对它们的硫化行为进行了评价 .X射线衍射 (XRD)、透射电镜 (TEM)、力学性能和光学性能的测试结果表明 ,由硫磺硫化体系制备的纳米复合材料为不透明和剥离型 .其原有的d0 0 1 衍射峰消失 ,有序层被剥离成 10 0～ 2 0 0nm的片层均匀分散在EPDM基体中 ,其力学性能有了极大的提高 ;而过氧化物体系制备的纳米复合材料为半透明和插层型 .对两种体系的硫化行为的评价结果表明 ,随着有机蒙脱土加入量的增加 ,硫磺 促进剂硫化体系的t90 延长 ,交联密度减小 ,最大 最小转矩也变小 ;

Nanocomposites based on ethylene-propylene-diene rubber (EPDM) and montmorillonite have been prepared via a melt process by using two vulcanization systems: a sulfur-accelerator system and a peroxide curing agent DBPH. The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that, the rubber molecules were found to be intercalated into the galleries of the organophilic montmorillonite (OMMT), and the silicate layers were exfoliated and dispersed uniformly in the rubber matrix of the nanocomposite cured by the sulfur-accelerator system, but the silicate layers were stacked and existed in the form of intercalated structure in the nanocomposite cured by the peroxide agent DBPH. The exfoliated nanocomposites were was opaque and had better mechanical properties than the intercalated ones which were semi-transparent. The two kinds of curing systems had different curing behavior evaluated by the Flory-Rehner equation. The vulcanization time (t(90)) was prolonged, and the maximum-minimum torque (MH-ML) decreased with increasing of OMMT content, and the EPDM become less crosslinked in the presence of OMMT for nanocomposites cured by sulfur curing system. However, the corresponding values of the nanocomposite cured by peroxide agent DBPH did not change obviously with the OMMT content.