在增韧剂作用下PPR的微观结构与性能

Structure and Properties of PPR with Toughening Agent

采用熔融挤出反应接枝技术自制的聚丙烯分子骨架接枝聚乙烯(PEP)为增韧改性剂对无规共聚聚丙烯(PPR)进行了改性,研究了增韧剂PEP对PPR/PEP共混物力学性能的影响。借助差示扫描量热分析(DSC)和偏光显微镜(POM)研究了PPR/PEP共混物的结晶行为。结果表明,添加PEP的质量分数为8%时,PPR/PEP共混物的室温和低温冲击强度分别提高了18.0%和30.6%,拉伸强度下降了3.4MPa;PEP的加入,使PPR在低温由脆性断裂转变为韧性断裂,PEP具有优异的低温增韧功能;PEP提高了PPR/PEP共混物的结晶温度和结晶度,具有成核作用,且细化了结晶晶粒。

Polyethylene was grafted onto molecular skeleton of polypropylene by melt extrusion grafting reaction to obtain a toughening modifier（called ＂PEP＂） for improving performance of ethylene propylene copolymer （PPR）. The influence of PEP on the mechanical properties of PPR/PEP blends and the crystallization behavior of blends were researched by differential scanning calorimeter （DSC） and polarizing optical microscope （POM）. The results indicate that when adding 8% PEP, the notched impact strength of PPR/PEP blends at room temperature and low temperature increase by 18% and 30.6% respectively, and the tensile strength of blends at room temperature decreases 3.4 MPa. The brittle fracture behavior of PPR is transformed into the ductile fracture behavior at low temperature. In addition, the crystallization temperature and crystallinity of PPR/PEP blends increase due to the nucleation effect of PEP, and the crystal grains of blends are refined.