HDPE增韧改性PP及增韧机理研究

HDPE Toughened Modification PP and Its Toughening Mechanism Research

以聚丙烯(PP)为基体、高密度聚乙烯(HDPE)为增韧剂,采用熔融共混的方式制备了PP/HDPE共混物,研究了HDPE的添加量对PP的增韧效果并探究了其增韧机理。结果表明,随着HDPE添加量的增加,所制备的PP/HDPE共混物的缺口冲击强度逐渐增大,当HDPE的添加量达到20%后,缺口冲击强度达到6.2 kJ/m^(2),较纯PP的3.9 kJ/m^(2)提高了59.0%,后继续提高HDPE含量,共混物的缺口冲击强度保持不变。增韧机理为PP/HDPE共混物在受到外力作用时,HDPE与PP的界面脱黏并形成空洞,空洞吸收能量。同时,HDPE充当应力集中点,产生“拉丝”现象,HDPE颗粒边缘向垂直于受力的方向延伸,应力从PP传递到HDPE,吸收能量。

In this study, using polypropylene(PP)as the substrate and high density polyethylene(HDPE)as the toughening agent, PP/HDPE blends were prepared by melt blending method, and the toughening effect of HDPE additive amount on PP was studied and the toughening mechanism was investigated.The results show that the impact strength of the prepared PP/HDPE blends gradually increases with the increase of HDPE additive amount, and when the HDPE addition amount reaches 20%,the impact strength of the blends no longer changes and reaches 6.2 kJ/m^(2),which is 59.0% higher than that of pure PP at 3.9 kJ/m^(2).Then the HDPE content is further increased, and the impact strength of the blend remains unchanged.The toughening mechanism is when the PP/HDPE blends are subjected to vertical external forces, the interface between HDPE and PP debonded and forms cavities, which absorbs energy.At the same time, HDPE acts as the stress concentration point and produces the phenomenon of“drawing”,the edge of HDPE particles is extended in the direction perpendicular to the force, the stress is transferred from HDPE particles to PP,and HDPE particles absorb the energy generated by the external force.