HDPE/纳米SiO2杂化材料的动态流变行为研究

摘要

Vinyl trimethoxysilane (VTMS) was grafted to the chain of the high density-polyethylene (HDPE) via melt grafting reaction. The tetraethoxysilane (TEOS) which acts as precursor was mixed with grafted HDPE,and then the HDPE/SiO2 hybrid materials were prepared by sol-gel process. The dynamic rheological behavior of the prepared high density-polyethylene/nano-silica hybrid composites was investigated by plate rheometer.Experimental results show that the complex viscosity (η*) of the composites increases with increasing the content of SiO2. When the SiO2 content of the hybrid composite reaches 1.2％, its complex viscosity η* increases suddenly and the shear thinning behavior appears. In the low frequency region, both the curves of the storage module G' vs. frequency ω and loss module G" vs. ω of the HDPE/SiO2 appear a second flat; and on the curve of the strain γ vs. storage module G', there appears two linear viscoelastic sections. These phenomena can be attributed to the links between the nano-SiO2 particles and polymer matrix in the hybrid system by chemical bonds and the uniform distribution of the nano-SiO2 particles; while when the nano-SiO2 content reaches 1.2％, the "solid-like" behavior may occur between the particles.%通过熔融接枝反应将乙烯基三甲氧基硅烷(VTMS)接枝到高密度聚乙烯(HDPE)分子链上,以四乙氧基硅烷(TEOS)为前驱体,加入接枝的HDPE中,通过溶胶-凝胶法(Sol-Gel)制备了HDPE/SiO2杂化材料,使用平板流变仪研究了纳米SiO2对HDPE/纳米SiO2杂化材料的动态流变行为的影响.结果表明,当SiO2含量达到1.2%时,复数黏度η*发生突变,并出现强烈的剪切变稀:低频区,储能模量G'、损耗模量G"出现第二平台;对应的应变y-G'曲线上,体系出现两段线性粘弹区域.这些现象表明由于杂化体系中纳米SiO2粒子与基体聚合物间通过化学键链接,并且均匀分布,在纳米粒子的含量达到1.2%时,粒子间就会发生似固体的关联行为.