高力学性能线性聚氨酯脲的合成与优化

摘要

A linear segmented poly(urethane-urea)(PEG400-PUU-PZZ) was prepared from poly(ethylene gly-col)(PEG400)co-initiated poly(D,L-lactic acid)macrodiol (PDLLA-PEG400-PDLLA),hexamethylene diiso-cyanate (HDI) as a coupling agent,and piperazine (PPZ) as a chain extender.The flexible PEG400 and rigid PPZ may endow high mechanical properties to PEG400-PUU-PZZ.In this study,the effects of chain extension time (1 to 5 h) and temperature (30 to 60 ℃) on the intrinsic viscosity of PEG400-PUU-PZZ were thoroughly investigated,and a new extension process of step heating,i.e.30 ℃ for 1 h,40 ℃ for 1 h and 50 ℃ for 2 h, was developed.Compared with constant temperature heating,the step heating resulted in higher Mn and narro-wer PDI of PEG400-PUU-PZZ.Correspondingly,its elastic modulus and yield strength were obviously en-hanced,suggesting that PEG400-PUU-PZZ could be a promising material in bone repairs.%聚乙二醇(PEG400)助引发DL-丙交酯形成的大分子二醇,经1,6-六亚甲基二异氰酸酯(HDI)偶联、哌嗪(PPZ)扩链后制得线性嵌段聚氨酯脲(PEG400-PUU-PPZ).因PEG400的增韧作用和PPZ环状结构的增强作用使得PEG400-PUU-PPZ可望具有优良的力学性能.通过系统研究扩链时间(1~5 h)和温度(30~60℃)对PEG400-PUU-PPZ特性黏度的影响,开发了一种梯度升温扩链的新工艺.结果表明,与恒温扩链相比,梯度升温扩链所得PEG400-PUU-PPZ的分子量更高、分子量分布更窄;相应地,其拉伸模量和屈服强度更高,表现出明显的强韧性材料的特征,可望用作骨组织修复材料.