熔融酯交换法绿色制备聚碳酸酯及抗菌改性

Green preparation of polycarbonate with melt transesterification method and its antibacterial modification

为了降低光气法合成聚碳酸酯(PC)过程中对环境的危害并解决熔融酯交换合成PC分子量较低的难题,以碳酸二苯酯和双酚A为原料,通过聚合工艺的控制提高PC的分子量。而且,为了提高PC的抗菌性能并提高抗菌剂的耐热性,合成不同氟碳链长度的全氟烷基链改性季膦盐抗菌剂,并采用热压成型制备PC抗菌薄膜。以PC的分子量为目标,优化了PC的聚合工艺,表征了PC及抗菌剂的结构,测试了抗菌剂的热稳定性,研究了PC抗菌薄膜的透光率与抗菌性能。结果表明,合成PC的最佳工艺为酯交换时间10 min、在250℃下缩聚40 min,可得到数均分子量超过12 000的PC;季氟己基膦盐抗菌剂具有良好的热稳定性,可以与PC通过热压法制备透光率最高为89%的抗菌薄膜;含4份季氟己基膦盐的PC薄膜具有最佳的抗菌效果,对金黄色葡萄球菌和大肠杆菌的抗菌率分别达到95%与94%。抗菌PC薄膜的合成绿色环保且抗菌性能优异,为食品包装提供更安全的解决方案。

In order to reduce the environmental hazards during the synthesis of polycarbonate(PC)by phosgene gas method,and to solve the problem that the PC synthesized by melt transesterification has low molecular weight,diphenyl carbonate and bisphenol A were used as raw materials and the molecular weight of PC was increased through the control of polymerization process.Moreover,in order to enhance the antibacterial effect of PC as well as improve the heat resistance of the antibacterial agent,quaternary phosphonium salts modified by perfluoroalkyl chains with different fluorocarbon chain lengths were synthesized,and PC antibacterial films were prepared by hot-pressing molding.Taking the molecular weight of PC as the target,the polymerization process of PC was optimized,the structure of PC and antibacterial agents were characterized and the thermal stability of the antibacterial agents were tested,the light transmittance and antibacterial properties of the PC antibacterial films were studied.The results show that the optimal process for synthesizing PC is 10 min of transesterification time,40 min of polycondensation at 250℃,which can lead to PC with a number average molecular weight of more than 12000.The antibacterial quaternary hexafluorohexyl phosphonium salt has good thermal stability,and it can be blended with PC for preparing antibacterial films with the highest transmittance of 89%by the hot-pressing method.And the PC film containing 4 phr quaternary hexafluorohexyl phosphonium salt has the optimal antibacterial effect,with antibacterial rate of 95%against Staphylococcus aureus and 94%against Escherichia coli.The synthesis of antibacterial PC film is green and environmentally friendly with excellent antibacterial performance,providing a safer solution for food packaging.