PET/TiO2复合材料非等温结晶行为的研究

采用表面接枝和聚合改性的方法,分别以γ-缩水甘油醚氧丙基三甲基硅烷(GPS)和甲基丙烯酸甲酯(MMA)对纳米二氧化钛(TiO_2)进行表面修饰,通过熔融共混制得聚对苯二甲酸乙二醇酯(PET)/GPS- TiO_2和PET/聚甲基丙烯酸甲酯(PMMA)-TiO_2纳米复合材料,用差示扫描量热法研究了其复合材料的非等温结晶行为,利用不同动力学模型对其结晶过程进行处理。结果表明：未处理的纳米TiO_2提高了PET的熔融温度和结晶温度；而经表面接枝的GPS-TiO_2和PMMA-TiO_2对PET的熔融温度和结晶温度的影响并不显著；不同表面特性的纳米TiO_2降低了PET的结晶度,但经表面接枝后的纳米TiO_2其影响程度减弱；用Jezi- omy法和莫志深法处理PET/TiO_2纳米复合材料的非等温结晶过程比较理想,PET,PET/PMMA-TiO_2,PET/ TiO_2,PET/GPS-TiO_2复合材料的结晶速率依次减小。

Study on nonisothermal crystallization behavior of PET/nano-TiO2 composites

The TiO_2 nanoparticles were subjected to surface modification usingγ-glycidoxypropyl trimethoxy silane(GPS)and methyl methacrylate(MMA)by surface grafting and polymerization and were melted and blended to produce polyethylene tereph- thalate(PET)/GPS-TiO_2 and PET/polymethyl methacrylate(PMMA)-TiO_2 nanocomposites.The non-isothermal crystallization behavior of the nonacomposites was studied by differential scanning calorimetry.The crystallization process was processed with different kinetic models.The results showed that the untreated TiO_2 nanoparticles can increase the melting temperature and crys- tallization temperature of PET;the surface grafted GPS-TiO_2 and PMMA-TiO_2 had no profound effect on the melting temperature and crystallization temperature of PET;and the TiO_2 nanoparticles with different surface characteristics can decrease the crystalli- zation temperature of PET,but the effect became weak after surface grafting treatment.Jeziorny and Mozhishen methods were sat- isfying in analyzing the non-isothermal crystallization process of PET/TiO_2 nanoparticles.The composites were in such an order from high to low crystallization rate:PET,PET/PMMA-TiO_2,PET/TiO_2,PET/GPS-TiO_2.