固相缩聚合成高分子量双酚A型聚碳酸酯

摘要

The new method for synthesizing high molecular weight bisphenol A polycarbonate(BPA–PC) by solid state polymerization from diphenyl carbonate with 4,4′-dihydroxy-diphenyl-2,2-propane(BPA) was studied with tetraethyl ammonium hydroxide as catalyst.The effects of particle size,molecular weight and end group mole ratio of the prepolymer,reaction temperature and reaction time were analyzed.BPA–PC with high molecular weight (Mn=52 572) and low polydispersity index(1.830) can be achieved when the reaction was conducted at 210℃for 8 h under vacuum.Thepolycarbonate showed higher intrinsic viscosity and higher melt temperature (258℃) with the particle size of prepolymer larger than 60 mesh.Higher-molecular -weight prepolymer resulted in higher-molecular-weight polymer and the stoichiometric imbalance in the prepolymer severely limited the maximum obtainable molecular weight.%研究了以碳酸二苯酯和双酚A为原料,有机胺为催化剂,固相缩聚法合成高分子量双酚A型聚碳酸酯(BPA–PC)的新工艺.探究了预聚体粉料颗粒大小、缩聚温度、缩聚时间、预聚体分子量及官能团比例等工艺条件对产品性能的影响.结果表明,以四乙基氢氧化铵为催化剂,大于60目(小于250 μm)的预聚体颗粒在210℃真空缩聚8 h,制得的缩聚体特性黏度较大.预聚体分子量越大,C6H5OH/OH官能团比例越接近1,缩聚物的分子量越大.在较佳工艺条件下,可得到数均分子量为52 572、分子量分布为1.830、熔点258℃、有一定结晶度的BPA–PC产品.