改性黏土对PET纳米复合材料结晶性能的影响

Effects of Modified Clay on the Crystallization Property of PET/Clay Nanocomposites

为了提高聚对苯二甲酸乙二醇酯(PET)的结晶速率,利用改性高岭土及有机化蒙脱土,分别采用熔融共混方法和熔融聚合方法制备了PET/高岭土纳米复合材料(KPET)和PET/蒙脱土纳米复合材料(MPET).采用差示扫描量热仪(DSC)研究了改性高岭土及有机化蒙脱土对PET结晶行为的影响;采用Avrami方程式对其等温结晶动力学进行了研究.结果表明:与PET相比,在低温区,KPET和MPET的冷结晶峰温明显向低温移动,过热程度明显降低,在高温区,KPET和MPET的过冷温度均明显向高温方向移动,过冷程度降低;结晶动力学研究中,在相同结晶温度下,MPET和KPET的半结晶时间t1/2均比PET明显缩短,KPET的t1/2明显比MPET相应的t1/2缩短;改性高岭土和有机化蒙脱土均为PET很好的成核剂,能提高PET的结晶速率;与有机化蒙脱土相比,改性高岭土对提高PET的结晶速率更加明显.

To improve the crystallization rate of poly ethylene terephthalate （PET）, PET/kaolin nanocomposites（KPET） and PET/montmorillonite nanocomposites（MPET） were prepared by melting blend methodwith modified kaolin and by melting polymerization method with organic montmorillonite, respectively. The effects of the modified kaolin and organic montmorillonite on the crystallization property of PET were investigated using differential scanning calorimeter（DSC）, and the isothermal crystallization kinetics of PET was studied with Avrami equation. The results show that compared with PET, in the region of low temperature, the superheating degree of KPET and MPET reduces obviously and the cold crystallization temperature decrease to low temperature markedly, and in the region of high temperature, the supercooling degree of KPET and MPET reduce obviously and the heat crystallization temperature rise to high temperature. The half crystallization time （t1/2） of KPET and MPET are shorter obviously than that of PET and t1/2 of KPET is shorter than that of MPET at the same crystallization temperature. The modified kaolin and organic montmorillonite are effective nucleating agent of PET. Both of them can increase the crystallization rate of PET. Furthermore, cornpared with the organic montmorillonite, the modified kaolin can more effectively improve the crystallization rate of PET.