“刚／柔”可控的新型聚氨酯材料的制备与表征

Preparation and characterization of a new kind of firm/soft adjusted poly(D,L-lactic acid)-polyurethane

背景:生物可降解聚氨酯是生物医用材料领域研究的一个热点。基于聚乳酸的智能型聚聚氨在生物医学领域具有广阔的应用前景。目的:以D,L-丙交酯、1,6-六亚甲基二异氰酸酯、1,4-丁二醇和1,4-丁二胺作为原料,从分子设计角度出发,制备一种基于聚乳酸的"刚/柔"可控多嵌段聚氨酯材料。方法:采用熔融聚合法首先合成羟基封端聚(D,L-乳酸),加入六亚甲基二异氰酸酯作为交联剂,再聚合得到基于聚(D,L-乳酸)的聚氨酯。通过红外光谱仪、核磁共振波谱仪、热重/差热综合热分析仪、万能材料试验机等仪器对羟基封端聚(D,L-乳酸)及基于聚(D,L-乳酸)的聚氨酯进行结构表征和性能测试。结果与结论:实验发现,经熔融聚合后的产物与预期分子结构设计相符,通过调节材料中反应物的比例调节硬段和软段的比例,从而实现调控该材料"刚/柔"转变程度(断裂伸长率从472%-112%)和"刚/柔"转变温度(玻璃化转变温度从36.33-44.04℃)。结果表明由可降解生物材料制备的基于聚(D,L-乳酸)的聚氨酯材料具备热敏效应,且其断裂伸长率和玻璃化转变温度可控,具备应用于生物医学工程领域的基础。

BACKGROUND： Biodegradable polyurethane is a focus in the field of biomedical materials. Poly（D,L-lactic acid）-polyurethane has a broad prospect in the biomedical field. OBJECTIVE： To prepare a new poly（D,L-lactic acid）-polyurethane based on the molecular designing, usingD,L-lactide, 1,6-hexamethylene diisocyanate, 1,4-butanediol and 1,4-butanediamine. METHODS The hydroxy-terminated poly（D,L-lactic acid） was synthesized by melt polymerization, and then1,6-hexamethylene diisocyanate was added as a crosslinker to produce poly（D,L-lactic acid）-polyurethane These products were characterized by Fourier transform infrared spectrometry, nuclear magnetic resonance spectrometer, thermogravimetry/differential thermal analyzer and Instron 1121 universal tester to explore the structures and performance. RESULTS AND CONCLUSION： The chemical structure of the products was consistent with the expected molecular structure. To adjust the proportion of reactants, we realized the control of the firm/soft transition degree （from 472% to 112% of the elongation at break） and firm/soft transition temperature （from 36.33 ℃ to 44.04 ℃ of the glass transition temperature）. These findings indicate that the biodegradable poly（D,L-lactic acid）- polyurethane has thermosensitive effect, and its elongation at break and glass transition temperature can be controlled, which is the application foundation in the field of biomedical engineering.