不同结晶性能聚合物/纳米SiO_2复合材料的制备与阻隔性能

The preparation and barrier properties of the polymer with different crystallization properties/nano-SiO_2 composites

选取3种偶联剂(KH550、KH560和KH570),将纳米SiO2进行改性,并采用熔融共混法分别与4种结晶性能不同的聚合物(HDPE、PP、PVC和PC)共混制备了一系列纳米复合材料(0～5%(质量分数)SiO2),并吹塑成薄膜。采用红外光谱(IR)、差示扫描量热仪(DSC)及扫描电镜(SEM)对纳米SiO2和复合材料的结构进行了表征,并对复合材料的力学性能、阻隔性能等进行了表征。结果表明,纳米SiO2与偶联剂均形成化学键合,改性后的纳米SiO2在各聚合物中分散较好,且在聚合物中起到异相成核的作用。在相同纳米SiO2含量下,SiO2对结晶性能不同的聚合物的结晶改善情况有差异,且纳米SiO2的异相成核作用在结晶性聚合物中更为明显,能使复合材料的结晶更为完善,结晶性能的改变与复合材料的阻隔性能能够形成一定关系。

Nano-composites were prepared by melt bending with different crystallization properties polymers （HDPE, PP, PVC and PC） and nano-SiO2 which were modified by different coupling agents （KH550, KH560 and KH570）. FT-IR, DSC and SEM have been performed in order to characterize the surface structures of the modified nano-SiO2 and the microstructure of composites. The mechanical properties and barrier properties were tested at the same time. The results indicated that： the chemical bonds formed between the nano-SiO2 and the coupling agents and the particles dispersed well in the polymers, moreover performed a heterogeneous nu- cleation effect. Compared with the amorphous composites （PVC/nano-SiO2 and PC/nano-SiO2）, the heteroge- neous nucleation effects of nano-SiO2 in crystalline composites （HDPE/ nano-SiO2 and PP/ nano-SiO2） were more obvious with the same content of nano-SiO2. Therefore the change of the crystallization of composites related to the barrier properties of composites.