增容剂流动性对PE-LLD/PS/PET三元共混物性能的影响

通过Friedel-Crafts烷基化反应,制备了线型低密度聚乙烯(PE-LLD)/聚苯乙烯(PS)(质量比50/50)增容母料,并将其与甲基丙烯酸缩水甘油酯(GMA)熔融接枝,制成接枝改性母料。在等质量的接枝改性母料中,添加不同用量的高熔体流动速率(MFR)的PE-LLD(HFPE-LLD),同时添加PS,使HFPE-LLD与PS的质量比始终保持在50/50,制成流动性不同的三元增容母料。将有效组分含量相同的上述三元增容母料,添加到PE-LLD/PS/聚对苯二甲酸乙二酯(PET)三元共混物中,考察了三元增容母料的流动性对共混物力学性能、动态流变性能及微观结构的影响。结果表明,随着三元增容母料流动性的增大,共混物的力学性能逐渐上升。相比未增容的共混物,添加了MFR为10.1 g/10 min的三元增容母料的共混物,力学性能达到最佳,其拉伸强度由8.2 MPa增至17.5 MPa,增幅为113.4%,断裂伸长率由2.3%增至23.5%,增幅为921.7%;在高频区,随着三元增容母料流动性的增大,共混物的储能模量、损耗模量、复数黏度逐渐上升,损耗因子逐渐下降。扫描电子显微镜照片显示,三元增容母料的流动性增大后,分散相粒径明显减小,相界面逐渐模糊。

Influences of Compatibilizer Fluidity on Properties of PE-LLD/PS/PET Ternary Blends

Friedel-Crafts alkylation reaction was used to prepare linear low density polyethylene(PE-LLD)/polystyrene(PS)(mass ratio 50/50)compatibilizing master batch(short for binary compatibilizing master batch below).Then the binary compatibilizing master batch was melt-grafted with glycidyl methacrylate(GMA)for preparing grafting modified master batch.Different amounts of PE-LLD with high melt flow rate(MFR)(HFPE-LLD)and corresponding amounts of PS were added into the grafting modified master batch with equal mass in order to keep the mass ratio of HFPE-LLD and PS at 50/50 consistently for preparing ternary compatibilizing master batch with different fluidity.Then the ternary master batch mentioned above with same contents of efficient components was added into PE-LLD/PS/polyethylene terephthalate(PET)ternary blends and influences of fluidity of the ternary master batch on mechanical properties,dynamic rheological properties and morphologies of the blends were investigated.The results reveal that with the improvement of fluidity of the ternary master batch,mechanical properties of the blends increase gradually.Compared to un-compatibilized blends,the blend compatibilized by the ternary master batch with MFR of 10.1 g/10 min reaches the best mechanical properties,the tensile strength of the blend increases from 8.2 MPa to 17.5 MPa with the growth of 113.4%and elongation at break increases from 2.3%to 23.5%with the growth of 921.7%.In high frequency regions,with the rise of fluidity of the ternary master batch,storage modulus,loss modulus and complex viscosity of the blend ascend gradually,loss factor descends gradually.Photographs of scanning electron microscopy show that sizes of dispersed phases decrease significantly and interfaces become indistinct gradually when the fluidity of the ternary master batch increases.