Abstract:

KH560 (3-glycidyloxypropyltrimethoxysilane) and nano-SiO₂ particles were filled into PET melt by extrusion process to increase the melt viscosity of the PET. When the KH560 and the SiO₂ particles were both filled at 2.5%(mass ratio), the melt viscosity-increasing effect was the best. Moreover, even the PET was not dried, the PET melt viscosity can also be improved by such chain extender, implying that it can be used as a regent to prevent the hydrolytic degradation of PET. Transmission electron microscopy imaging showed that the dispersion of nano-SiO₂ in PET was well. The reaction mechanism between KH560, SiO₂ and PET was confirmed by FTIR. The grafting of PET molecules to SiO₂ nanoparticles was analyzed by TGA, and the graft ratio was 72%. The crystallization behavior of the PET/ SiO₂ composites was studied by DSC. When the KH560 and SiO₂ nanoparticles were both filled at 2.5% (mass ratio), the crystallinity of PET/nano-SiO₂ composite is the lowest and the comprehensive mechanical properties were the best.

Key words: polyethylene terephthalate, silicon dioxide, reaction extrusion, viscosity increasing, chain extender

摘要：

以KH560（3-缩水甘油基氧基丙基三甲氧基硅烷）和纳米SiO₂颗粒复配作为扩链剂，采用“一步法”反应挤出增黏聚对苯二甲酸乙二醇酯（PET）。KH560和SiO₂的添加量均为PET质量分数的2.5%时，增黏效果最好。并且在PET不干燥的情况下，KH560和SiO₂复配也可增加PET的黏度，可用作PET的扩链剂和防水解剂。经透射电镜观察，发现SiO₂在PET中的分散状况良好。用FTIR研究了KH560、SiO₂、PET三者之间的反应机理。用TGA分析了SiO₂的接枝率，发现接枝率高达72.0%。用DSC对PET/纳米SiO₂复合材料的结晶行为进行了研究，并讨论了结晶行为对力学性能的影响。当KH560和SiO₂的添加量均为PET质量分数的2.5%时，结晶度最低，综合力学性能最好。

关键词: 聚对苯二甲酸乙二醇酯, 二氧化硅, 反应挤出, 增黏, 扩链剂