SiO_2纳米粒子填充PS/PMMA共连续共混物的应力松弛行为

Influence of Hydrophilic SiO2 Nanoparticles on the Shear Stress Relaxation Behavior of Co-Continuous PS/PMMA Blends

采用流变测试和扫描电子显微镜技术,考察了亲水性SiO2纳米粒子对具有共连续结构的聚苯乙烯(PS)/聚甲基丙烯酸甲酯(PMMA)(体积比50/50)共混物在步阶剪切应变下应力松弛行为的影响。研究表明,PS/PMMA共混物呈现两步应力松弛行为,即来源于本体聚合物的较快的松弛以及来源于界面的较慢的松弛。SiO2粒子的加入细化了共混物的形态尺寸,加速了共混物第二阶段的松弛行为。同时,实验结果进一步表明,填充共混物应力松弛行为的加快主要是由于SiO2的加入引起形态细化造成的,而并非组分粘弹性的变化。

Rheological technique and scanning electron microscopy（SEM） have been utilized to detect the influence of hydrophilic SiO2 nanoparticles（up to 2%） on the stress relaxation behavior of co-continuous polystyrene（PS）/poly（methyl methacrylate）（PMMA）（50/50） blends,which was subjected to a step shear strain.The stress relaxation of blends displays a two-step behavior,i.e.,the fast relaxation process which corresponds to the relaxation of bulk polymer,and the second slower relaxation process due to the recovery of co-continuous morphology.The addition of hydrophilic SiO2 nanoparticles accelerates the stress relaxation rate of the second stage of blends.Furthermore,the results suggest that the accelerated stress relaxation behavior of these blends is due to the morphology refinement caused by the incorporation of SiO2 nanoparticles,rather than the viscoelastic enhancement of component.