聚醚胺基聚脲的合成及其性能

Synthesis and Performance of Degradable PEA-based Polyurethane

以乙二胺、氯乙醇和环氧氯丙烷为原料制备线型聚醚胺(PEA),分别用脂肪族二异氰酸酯(IPDI或HDI)与PEA进行交联,制得网络结构聚脲P1A,P1,P1B和P2,研究了聚脲的结构和热分解性能及其在水溶液中的酶促降解性.结果表明,聚合物的热分解过程主要有2个阶段:由酰胺键断裂引起的失重,P1A,P1,P1B和P2失重速率最大时的温度分别为337.3,367.6,372.7和367.4℃;由PEA主链断裂引起的失重,P1A,P1,P1B和P2失重速率最大时的温度分别为440.5,422.5,444.9和482.7℃.P1在有木瓜蛋白酶的PBS缓冲溶液中(pH=7.42),60d后失重率超过40%.随着交联剂IPDI用量增加,聚合物的热分解温度提高,生物降解速率降低.

A linear polyether amine （PEA） was synthesized by ring-opening polymerization using ethylene diamine, 2-chloroethanol and epoxy chloropropane. PEA was then cross-linked with diisocyanates to produce crosslinkable polymers, P1A, P1, PlB and P2. The synthesized crosslinkable polyurethanes were characterized by IR and 1^H-NMR spectra, and their thermal stabilities and degradabilities were investigated by TG and DSC. Their biodegradabilities were studied in PBS aqueous buffer （pH 7.42） in the presence of papain. The results showed that the thermal degradation of polymers mainly consisted of two stages： the first weight loss should be due to the break of amide bond in the polymers, during which the temperatures at the maximum weight loss rate for P1A, P1, P1B and P2 were 337.3, 367.6, 372.7 and 367.4 ℃ respectively; the second weight loss should be due to the break of main chain of PEA, the temperatures at the maximum weight loss rate for P1A, P1, P1B and P2 were 440.5, 422.5, 444.9 and 482.7 ℃ respectively. The weight loss for P1 was over 40% in aqueous buffer in the presence of papain after 60 d. The biodegradation rates of polymers decreased when the quantities of cross-linking agents increased.