SiO2/EPDM复合材料微观形态与动态力学性能的关系

利用DMTA方法研究了分散剂、硅烷偶联剂以及二者并用对二氧化硅增强乙丙橡胶复合材料动态力学性能的影响,采用扫描电镜和橡胶加工分析仪测试了填料在橡胶基体中的分散和填料在基体中形成的填料网络结构,利用结合胶测试研究了复合材料中填料橡胶之间的相互作用程度。实验结果表明:按照空白样和采用分散剂、硅烷偶联剂、分散剂+硅烷偶联剂对SiO₂进行表面处理,填料在橡胶基体中的分散程度提高,填料填料的相互作用逐渐弱化,填料网络结构逐渐减弱,橡胶复合材料在低应变下的储能模量逐渐降低,抗滚动阻力性能逐渐提高。同时,结合胶含量逐渐提高,玻璃化转变峰逐渐变宽,复合材料的抗湿滑性能逐步提高分散剂与硅烷偶联剂并用改性二氧化硅对橡胶复合材料性能提高有协同作用。

Relations between morphology and dynamic mechanical properties of SiO2/EPDM composites

In this paper the dynamic mechanical properties of EPDM composites reinforced by nano-silica untreated and treated by a dispersant, a silane coupling agent (TESPT), the dispersant together with silane coupling agent were investigated. Scan electric microphotograph, rubber processing analyzer and bound rubber testing were also applied to further testify the distribution and dispersion of agglomerates, the filler-filler interactions network and the filler-polymer interactions in the rubber matrix, respectively. The relations between the dynamic mechanical properties and the morphology of the filler in the matrix were discussed. It is shown, from the experimental results, that compared with those of the composite reinforced by untreated silica, the dispersion of the silica and the silica-rubber interaction are both improved by the dispersant and the silane coupling agent, respectively. The better dispersion and the improved bound rubber are responsible for the lower dynamic storage modulus and the better rolling resistance of the rubber composites. A greater improvement in the dynamic mechanical properties of the composites is obtained in the composite treated by the dispersant together with the silane coupling agent. Their effects are additive to some extent.