水解诱导聚乳酸及其碳基纳米复合材料分子有序与结晶的研究

项目名称： 水解诱导聚乳酸及其碳基纳米复合材料分子有序与结晶的研究

项目编号： No.51473137

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 王勇

作者单位： 西南交通大学

项目金额： 78万元

中文摘要： 与以往只关注聚乳酸质量损失及其水解速率变化的表象研究不同，本项目以聚乳酸及其碳基纳米复合材料在水解过程中的凝聚态结构变化为研究对象，着重阐述水解诱导聚乳酸分子有序和结晶的相关机制及影响因素。通过研究聚乳酸在水解初期的化学反应过程及分子量变化，建立分子量随水解条件变化的动态演化模型，掌握纳米粒子对聚乳酸水解动力学的影响机制；采用FTIR、Raman等研究分子链构象、无序-有序结构相互转化及分子链松弛行为，阐明水解诱导聚乳酸分子有序结构的形成机制；通过WAXD、DSC、SEM等研究水解过程中晶体的成核生长，研究晶体的形态、晶型等对水解条件和样品初始微观结构的依赖性；比较研究纳米复合材料水解过程中的结构变化，揭示纳米粒子对聚乳酸分子有序和结晶的作用机制。阐明上述科学问题，既有助于认识和控制聚乳酸的降解过程，又能加深对其作为生物可降解材料释放内部包裹物机理的理解，因而具有重要的科学意义和应用价值。

中文关键词： 聚乳酸；纳米复合材料；水解；分子有序；结晶

英文摘要： Different from the previous researches which only pay attention to the weight loss and the variation of hydrolytic degradation rate of poly(L-lactic acid) (PLLA), this project investigates the evolution of condensed structures of pure PLLA and its carbon-based nanocomposites during the hydrolytic degradation process, and the main attention is focused on the formation mechanisms of molecular ordering structure, the crystallization mechanisms, and the corresponding determinable factors. The chemical reaction process in the early stage of the hydrolytic degradation will be investigated. The changes of molecular weight and molecular weight distribution before and after being hydrolyzed will be measured to find the dynamic evolution model of molecular weight with hydrolytic degradation conditions, and to further understand the effects of nanoparticles on the hydrolytic degradation kinetics of the PLLA. The conformation of molecular chains, the transformation between disordered and ordered structures, and the relaxation behaviors of molecular chains will be comparatively investigated by using FTIR, Raman, etc. WAXD, DSC, and SEM, etc. will be used to explore the nucleation and growth of crystalline structure. Furthermore, the dependence of crystalline morphology and crystal form on the hydrolytic degradation conditions and the initial microstructures of the samples will be clarified. Through comparatively investigating the microstructure changes of the PLLA nanocomposites during the hydrolytic degradation process, it is expected that the roles of morphologies and microstructures of the nanoparticles can be well understood. It is believed that the clarification of the above scientific issues not only facilitates us to understand and control the hydrolytic degradation process of the PLLA but also helps us understand the mechanism for the inclusion release when PLLA is used as the biodegradable material. Therefore, this work exhibits important scientific significance and application value.

英文关键词： Poly(L-lactic acid);Nanocomposites;Hydrolytic degradation;Molecular ordering;Crystallization