【作者】 舒荣德；

【导师】 陈际达；

【作者基本信息】 重庆大学 ， 药物化学， 2011， 硕士

【摘要】 聚乳酸(PLA)具有优良的生物相容性、生物可降解性以及生物可吸收性,因此聚乳酸材料已广泛用于药物载体、组织工程支架等方面,是生物可降解材料领域研究的热点。本课题以D,L-丙交酯为原料,辛酸亚锡为催化剂,1,4-丁二醇、赖氨酸、胶原酶敏感性多肽为引发剂,1,6-六亚甲基二异氰酸酯(HDI)为扩链剂,制备出一种亲水性较强的聚乳酸嵌段聚酯。采用氢核磁共振(~1H-NMR)、接触角、傅里叶红外光谱(FTIR)、紫外可见分光光度法(UV)、以及粘均分子量、降解分子量等方法对合成的产物:双端羟基聚乳酸寡聚体HO-PLA-BDO-PLA-OH、HO-PLA-Lys-PLA-OH、胶原酶敏感性聚乳酸寡聚体以及扩链产物进行了结构表征和性能测试。获得的主要结论如下:1:采用具有双端羟基的1,4丁二醇引发丙交酯开环聚合,辛酸亚锡为催化剂,通过控制1,4-丁二醇和丙交酯的反应投料比,得到了不同分子量的双端羟基聚乳酸寡聚体HO-PLA-BDO-PLA-OH。经HDI在二氧六环中扩链后分子量提高了3倍。2:赖氨酸含有双端氨基,利用-NH2的活泼H,引发丙交酯开环聚合,得到了双端羟基聚乳酸寡聚体HO-PLA-Lys-PLA-OH,并用HDI对双端羟基聚乳酸寡聚体HO-PLA-Lys-PLA-OH进行扩链,考察了不同的反应温度和反应投料比对扩链的影响,研究表明:扩链产物的粘均分子量随着HDI和寡聚体的反应投料比增加而增加,当反应温度为70℃,3h,辛酸亚锡催化剂用量为0.3wt%,反应投料比为2:1,扩链后产物的粘均分子量是扩链前的3.6倍。3:根据胶原酶敏感性多肽(GGGLGPAGGK)和赖氨酸都含有双端-NH2的特点,采用多肽引发丙交酯开环聚合,得到了双端羟基的胶原酶敏感性聚乳酸寡聚体,并用HDI对寡聚体进行扩链,生成了线性的胶原酶敏感性聚乳酸嵌段聚酯,扩链产物的分子量提高了3倍。4:通过产物接触角的测定表明:由赖氨酸和多肽引发制得的聚乳酸寡聚体的亲水性明显好于由1,4-丁二醇引发制得的聚乳酸寡聚体的亲水性;扩链后随着聚乳酸分子量的增加,扩链产物的接触角相应增加,亲水性略有降低。更多还原

【Abstract】 Polylactic acid(PLA) has attracted considerable attention of biomedical materials researchers due to its full degradability,renewability,good biocompatibilty.It has been used as drug delivery carriers,tissue engineering scaffolds and so on.Polylactic acid block copolymers were synthesized via lactide ring-opening polymerization with stannous octoate as catalyst,butanediol,lysine and collagenase sensitive peptide as initiators,1,6-diisocyanatohexane as chain extender.The related oligomers and chain extension products were characterized with 1H-NMR,contact angle testing,FTIR,UV,viscosity-average molecular weight and alkaline degradation molecular weight.The main conclusions were included as follows:1:Oligomers of dihydroxyl-terminated molecule (HO-PLA-BDO-PLA-OH) were synthesized via lactide ring-opening polymerization with butanediol as initiator and stannous octoate as catalyst.The chain extension products of the oligomers were synthesized with HDI in dioxane, and the viscosity average molecular weight of chain extension products was 3 times larger than those of oligomers.2:Oligomers of dihydroxyl-terminated molecule (HO-PLA-Lys-PLA-OH) were synthesized via lactide ring-opening polymerization with lysine as intiator which has diamino-terminated active hydrogen.Then polymers were synthesized through chain extension oligomers HO-PLA-Lys-PLA-OH with HDI in dioxane.The experimental conditions, such as, chain extension temperature and molar ratio between HDI and oligomer were studied.The results indicated that chain extension products viscosity average molecular weight increased with the increasing molar ratio.The optimized synthesis conditions were reaction 3h at 70℃with stannous octoate 0.3wt% of oligomer and molar ratio 2:1 between HDI and HO-PLA-Lys-PLA-OH,and the viscosity average molecular weight of chain extension products was 3.6 times larger than those of oligomers.3:The optimized conditions of HO-PLA-Lys-PLA-OH was used in the synthesis of collagenase sensitive lactic acid oligomer owing to the similar structure between lysine and collagenase sensitive peptide which they both have diamino-terminated.Then collagenase sensitive polylactic acid block copolymers was synthesized through chain extension oligomer with HDI.Viscosity average molecular weight of block copolymers were 3 times larger than those of oligomers. 4 : The hydrophilicity of HO-PLA-Lys-PLA-OH and collagenase sensitive polylactic acid oligomer were better than that of HO-PLA-BDO-PLA-OH oligomer based on contact angle testing results . The contact angle test indicated that hydrophilicity of chain extension products decreased with the inceasing molecular weight of chain extension products.更多还原