钛酸四乙酯催化酯交换缩聚法合成聚醚型聚氨酯

以钛酸四乙酯(TET)为催化剂,聚四氢呋喃醚二醇(PTMG)和1,6-六亚甲基二氨基甲酸甲酯(HDC)为原料,1,4-丁二醇为扩链剂,酯交换缩聚合成了聚醚型聚氨酯(PEPU)弹性体。以二丁基氧化锡(DBTO)催化合成的PEPU为参考,通过红外光谱(FTIR)、凝胶色谱(GPC)、热重分析(TGA)、力学性能与光学性能测试表征TET的催化效果。通过一系列单因素实验探讨了缩聚温度、缩聚时间、预聚温度、预聚时间对PEPU特性黏度的影响规律。结果表明,TET比DBTO催化制得的PEPU热性能更好,力学性能更优。较佳的制备工艺为:预聚阶段温度为110℃,压力为0.070MPa,时间为20min;160℃下高真空缩聚110min.

Tetraethyl titanate as a catalyst for the synthesis of polyether-polyurethanes by transurethane polycondensation

Thermoplastic polyether polyurethanes (PEPUs) were prepared by a transurethane polycondensation method with poly(oxytetramethylene) glycol (PTMG) as a soft segment,dimethyl- hexane-1,6-dicarbamate (HDC) and 1,4-butanediol (BDO) as hard segments in the presence of tetraethyl titanate (TET). FTIR,GPC,TGA and mechanical and optical property tests were used to characterize the catalytic performance of TET and compare with a standard catalyst of dibutyltin oxide (DBTO) . The effects of synthesis conditions such as polycondensation temperature,polycondensation time,prepolymerization temperature and prepolymerization time on the intrinsic viscosity of PEPUs were discussed by a series of single factor experiments. The results showed that PEPU with TET as a catalyst exhibited better thermal and mechanical properties than PEPU with DBTO as a catalyst did. And the optimal processing conditions were:the prepolymerization reaction was carried out at 110℃ for 45min under a reduced pressure of 0.070MPa and the polycondensation reaction was conducted at 160℃ for 110min under vacuum.