PET/纳米SiO2复合体系结晶性和SiO2粒子分散性研究

将改性后的纳米SiO2加入单体EG中超声波分散,然后与TPA搅拌混合置入反应釜中,制备PET/纳米SiO2复合材料.研究了纳米SiO2的用量及其分散形式.用傅立叶红外、SEM分析和观察纳米SiO2在复合材料中的结构和形态,用示差扫描量热法(DSC)分析PET复合材料的结晶行为.结果表明,PET/SiO2复合材料中的纳米氧化硅已经融入到PET基体中.将纳米SiO2在EG中直接用超声波分散,再与TPA聚合得到的复合材料中纳米SiO2粒子存在严重团聚现象;而纳米SiO2和分散剂PEG同时加入EG后用超声波分散,再进行聚合可以明显提高其分散性.DSC分析表明,PET/SiO2复合材料体系的结晶放热峰的宽度增大.当SiO2的量不超过2%时,能够略微提高PET的结晶温度,使结晶过冷度和结晶速率减小;当SiO2含量为3%时,结晶速率常数增大.与非等温结晶动力学分析得到的结果相同.

Study on the Dispersivity of Nano-SiO2 in PET and Crystalline Properties of PET/Nanometer SiO2 Composites

Composites of PET/nano-SiO_2 are prepared by putting the modified nanometer SiO_2 into the monomer EG and dispersing by ultrasonic wave. Then they mixed with TPA, and lay it in the autoclave. The content and the dispersed form of nanometer SiO_2 in PET/nano-SiO_2 are investigated. The structure and morphology of nanometer SiO_2 are examined by IR and SEM respectively. The crystallization behavior of the composites is determined by DSC. The results show that nanometer SiO_2 particles of PET/nano-SiO_2 composites are blended in the matrix of the PET entirely. Directly dispersing nanometer SiO_2 in EG and then being polymerized with TPA lead to an aggregation form of SiO_2 in the composites, whereas the dispersion is improved obviously when nanometer SiO_2 and PEG are added in EG simultaneously, and then be polymerized. The result of DSC shows that the width of thermo-positive peak of the composites is enlarged. When the content of SiO_2 is less than 2%, the under-cooling and crystalline rate will decreas, and the crystal temperature will increase slightly. When the content of SiO_2 reaches to 3%, the constant of crystalline rate will increase. The investigation of the none-isothermal crystallization dynamic obtaines the same tendency.