低填充SiO2/聚丙烯纳米复合材料的拉伸特性

摘要

通过对纳米SiO2辐照接枝聚合改性，结合熔融共混工艺制备了低填充SiO2/PP纳米复合材料。发现在一定拉伸速度和粒子含量下，经辐照改性的SiO2/PP纳米复合材料韧性得到显著提高，同时强度也有所增加。随拉伸速度的升高，纳米复合材料的模量和强度逐渐增大,而韧性则随之下降。断面扫描电镜观察表明，改性纳米粒子填充复合材料韧性提高的机理以空化和基体大面积剪切屈服为主。%SiO2 nanoparticles were modified through irradiation grafting polymerization and then melt-mixed with polypropylene (PP) to prepare low filler loaded SiO2/PP nanocomposites (typically less than 3vol%). Tensile tests under certain crosshead speeds showed that the addition of grafted nano-SiO2 into PP resulted in a significant increase in toughness and a slight enhancement of yield strength of PP. With a rise in tensile speed, modulus and strength of the nanocomposites increased, while the toughness decreased. Electronic microscopic observation of the fracture surface suggested that the toughening mechanisms of the modified SiO2/PP nanocomposites were controlled by microscopic cavitation and plastic deformation of matrix.