HIPS/HDPE共混物的动态黏弹行为与相形态

Dynamic Viscoelastic Behavior and Phase Morphology of HIPS/HDPE Blends

采用动态流变测试和扫描电子显微镜技术,考察高抗冲聚苯乙烯(HIPS)/高密度聚乙烯(HDPE)共混物的动态黏弹行为与相形态,对比1%(质量分数,下同)的纳米和微米CaCO_3对HIPS/HDPE(30/70)不相容共混物的增容效果。结果表明:当HDPE小于30%时,HIPS/HDPE共混物在低频区的复数黏度和储存模量均显示出明显的正偏差,而当HDPE大于30%时,则呈现负偏差;前者与HDPE和PB粒子间的相互作用相关,而后者归因于HDPE基体与PS分散相之间较弱的界面相互作用。当HIPS为基体时,HDPE分散相粒子呈现较宽的尺寸分布;而当HDPE为基体时,PS分散相呈现双模尺寸分布,对应于两种不同类型的PS分散相粒子的存在。1%的纳米CaCO_3对HIPS/HDPE(30/70)不相容共混体系起到了一定的增容效果,CaCO_3纳米粒子主要位于HIPS/HDPE相界面以及HDPE连续相内;而微米CaCO_3对该共混体系仅起到了增黏而非增容作用,CaCO_3微米粒子仅位于HDPE连续相内。

The dynamic viscoelastic behavior and phase morphology of high impact polystyrene （HIPS）/high density polyethylene （HDPE） blends were investigated by dynamic rheological test and scanning electron microscopy （SEM）. The compatibilizing effect of 1%（mass fraction, same as below） micron-CaCO3 and nano-CaCO3 on HIPS/HDPE（30/70） immiscible blend was compared. The results indicate that the complex viscosity and storage modulus of HIPS/HDPE blends at low frequencies show positive deviation from the mixing rule when HDPE is less than 30%, while negative deviation is observed when HDPE is more than 30%. The former is related to the interaction between HDPE and PB particles and the latter is attributed to the poor interfacial interaction between HDPE matrix and PS particles. When HIPS is the matrix phase, HDPE particles display broad size distribution. When HDPE acts as a matrix phase, PS dispersed phase exhibits bimodal size distribution corresponding to the presence of two different types of PS dispersed particles. 1% nano-CaCO3 has a certain compatibilizing effect on HIPS/HDPE（30/70） immiscible blend, which is mainly located at HIPS/HDPE interface and in the HDPE matrix, while micron-CaCO3 acts as viscosifier rather than compatibilizer, which is confined in the HDPE matrix.