纳米TiO2对PET结晶行为、流变和力学性能的影响

通过二阶熔融共混法制备了聚对苯二甲酸乙二醇酯(PET)／纳米二氧化钛(TiO2)复合材料，并使用TEM对纳米TiO2在基体中的分散状态进行了观察。研究了纳米TiO2对PET的结晶行为、流变与力学性能的影响。发现纳米TiO2粒子在PET基体树脂中起到了成核剂的作用，明显提高了基体树脂结晶温度、结晶速率，并使材料的DSC曲线形状发生显著变化，出现熔融双峰。纳米TiO2的加入明显降低了PET的熔体粘度。并且发现在较低和较高剪切速率区，PET／纳米TiO2体系粘度随剪切速率的变化趋于平缓；而在中等剪切速率区，其流动行为表现出假塑性流体特性。纳米TiO2对PET有明显的增强增韧作用，加入3％可使材料的拉伸和断裂强度提高25％；加入1％可使材料缺口冲击强度提高10％。

Effect of Nano TiO_2 on Crystallization,Rheological Behavior and Mechanical Properties of PET

PET/nano TiO 2 composites were manufactured by melt blending process and the dispersion of nano TiO 2 in the matrix was observed by TEM. Effects of nano TiO 2 on crystallization behavior, mechanical and rheological properties of the composite were studied.It was found that nano TiO 2 acted as a nucleating agent in PET; increased the crystallization temperature and crystallization rate of PET obviously. Double melt peak occurred in DSC curves. Incorporation of nano TiO 2 lowered the melt viscosity of PET. It was also noted that in the lower and higher shear rate areas, the viscosity of the system changed slowly with shear rate, but in the middle area of medium shear rate,its rheological behavior exhibited pseudoplastic. TiO 2 had obvious reinforcing and toughening effect on the system. Incorporation of 3 % TiO 2 increased the tensile strength of the system by 25 %; incorporation of 1 % TiO 2 increased the notched impact strength of the system by 10 %.