β成核剂对聚丙烯抗冲击性能的影响

Influences of β nucleating agent on the impact property of PP

采用广角X射线衍射仪、差示扫描量热仪等测定了β成核剂改性聚丙烯(PP)(β-PP)中β晶含量,研究了β晶含量与PP悬臂梁缺口冲击强度的关系、β成核剂的成核热稳定性及β成核剂对PP结晶速率的影响。结果表明:随着β成核剂用量的增加,PP的抗冲击性能提高,但其冲击强度与β晶含量不成正比;β晶含量与β-PP的结晶度达到平衡时,PP冲击强度最佳,当β成核剂质量分数为0.05%时,β-PP的冲击强度最高,达82.4 k J/m2,此时β晶含量为75.78%,β-PP结晶度为77.3%;加入β成核剂使PP的结晶速率降低,较快的降温速率会减少β晶的形成。

β-crystal content in the polypropylene（PP）modified by β nucleating agent（β-PP）was determined via wide angel X-ray diffraction（WAXD）and differential scanning calorimetry（DSC）. The relation between β-crystal content and Izod notched impact strength,the thermal stability of β nucleating agent were studied, and the effect of the β nucleating agent on the crystalline rate of PP was also studied. The results show that the impact property of PP is improved with the increase of β nucleating agent content, while the impact strength is not proportional to the β-crystal content. The impact strength of PP reaches best when the β-crystal content equilibrates with the crystallinity of β-PP. The impact strength of β-PP reaches maximum value（82.4 k J/m2）, while the β-crystal content and crystallinity of β-PP are 75.78% and 77.3%respectively when the mass fraction of β nucleating agent is 0.05%. The addition of β nucleating agent decreases the crystalline rate and the faster cooling rate will reduce the formation of the β-crystal.