论文部分内容阅读
利用TiO2-SiO2(PVP)凝胶基催化剂(TSP),无溶剂条件下,以碳酸二苯酯与1,4-丁二醇为单体,采用常压预聚和真空缩聚两步熔融酯交换法合成了聚(对亚丁基)碳酸酯(PBC),考察了工艺条件,并对PBC的结构及物理性质进行了表征.实验结果表明,最佳工艺条件如下:预聚时间为2 h,预聚温度为220~230℃(N2保护),缩聚温度为220℃,缩聚压力<300 Pa,催化剂用量为0.15 wt%.优化条件下,PBC的特性黏数为1.12dL/g,Mn为49000,Mw为101000,PDI为2.07,Tg为-32.32℃,端羟基含量为6.2×10-4mol/g,苯酚残留量为5.26 wt%.在此工艺条件下,通过控制副产物苯酚的蒸出速率及其量,可以实现产品聚合度的可控,且苯酚几乎能够完全回收.
Using TiO2-SiO2 (PVP) gel-based catalyst (TSP), solvent-free conditions, diphenyl carbonate and 1,4-butanediol as monomers, using two steps of atmospheric pre-polymerization and vacuum polycondensation transesterification Poly (p-butylidene) carbonate (PBC) was synthesized by the method and the process conditions were investigated.The structure and physical properties of PBC were characterized.The experimental results show that the optimum process conditions are as follows: the prepolymerization time is 2 h, The polyaddition temperature was 220 ℃, the polycondensation pressure was less than 300 Pa, and the amount of catalyst was 0.15 wt%. The intrinsic viscosity of PBC was 1.12dL / g and Mn was 49000 under the optimized conditions, Mw was 101000, PDI was 2.07, Tg was -32.32 ℃, terminal hydroxyl content was 6.2 × 10-4mol / g, phenol residue was 5.26 wt% .In this condition, by controlling the byproduct phenol distillation rate and The amount of the product polymerization degree can be controlled, and the phenol can be almost completely recovered.