新型α和β成核剂对PP结晶和力学性能的影响

Effects of New Novel α/β Nucleators on Mechanical and Crystallization Propreties of PP

在聚丙烯(PP)中加入两种新型成核剂:二苄叉山梨醇衍生物YS-688(α成核剂)和芳酰胺类化合物TMB-5(β成核剂),通过密炼–挤出的方法制备了PP/成核剂共混物材料。通过偏光显微镜、X射线衍射、差示扫描量热和力学性能测试研究了这两种成核剂对共混物结晶和力学性能的影响。结果表明,两种成核剂在适量时均能提高PP的结晶速率和结晶度,细化晶粒,且使晶体界面模糊,其中TMB-5具有较强的诱导PPβ晶成核的能力,当其质量分数为0.075%时,可使PP形成树枝状的β晶,而YS-688未改变PP的晶型,只生成了α晶。YS-688可提高共混物的拉伸强度,而TMB-5对共混物的拉伸强度影响很小;当两种成核剂质量分数均为0.075%时,共混物的韧性最好,相对于纯PP,PP/YS-688共混物的常温和–30℃缺口冲击强度分别提高了37.41%和12.76%,拉伸强度提高了11.11%;PP/TMB-5共混物的常温和–30℃缺口冲击强度分别提高了100%和55.41%。

Polypropylene （PP）/nucleating agent blends were prepared by mixing and extruding through adding two new nucleating agents including dibenzylidene sorbitol derivative YS-688 （α-nucleating agent） and aryl amides TMB-5 （β-nucleating agent） into PP. The effects of the two nucleating agents on the crystallization and mechanical properties of PP were studied by PLM,XRD, DSC and mechanical property tests. The results show that the two nucleating agents with appropriate content can increase the rate of crystallization and the degree of crystallinity, re？ne grains and blur crystal interface. TMB-5 has a stronger ability of inducing β-crystal nucleation of PP and when the mass ratio of TMB-5 is 0.075%,a dendritic β-crystal is formed inside PP. The crystalline phase of PP isn′t changed with the addition the YS-688 and only α-crystal is formed. YS-688 can improve the tensile strength of the blend and TMB-5 has slight impact on tensile strength. When the mass fraction of the two nucleating agents is 0.075%, the toughness of the blend is best,compared to pure PP,the notched impact strength at normal temperature and low temperature （–30℃ ） of PP/YS-688 is increased by 37.41% and 12.76% respectively, and the tensile strength increases by 11.11%, moreover, the notched im-pact strength at normal temperature and –30℃ PP/TMB-5 is increased by 100% and 55.41% respectively.