氯化聚丙撑碳酸酯的结构与性能研究

At present, polypropylene carbonate (PPC), the copolymerization product of carbon dioxide and propylene oxide, have been put into the stage of industrial production. However, since it has a glass transition temperature (Tg) of commonly 30-40°C and is amorphous, there are defects such as large brittleness at low temperature, poor dimensional stability at high temperature, and the like, limiting its wide application. More recently, our research results show that the properties of the PPC after chloration become totally different from those of the PPC before chloration. The chlorinated PPC (CPPC) possess excellent wettability and adhesion with metal, wood, and polar polymers such as polycarbonate, polyvinyl chloride, et al, and can used as hot melt adhesive and coating materials. Moreover, as compatilizer, it can effectively improve the properties of the PPC composites with starch or nature fibers. However, we lack fundamental understanding for the molecular structure and the relation between the structure and properties of this new born material. In this project, we devote to study the following question: (1) the molecular structure of CPPC and its chloration process dependence; (2) the relation between the molecular structure of CPPC and its glass transition temperature, thermal and mechanical properties; (3) the relation between the molecular structure of CPPC and its wettability, adhesion, film formation as well as compatibilization. The purpose is to provide the scientific basis and technical support for the application of CPPC.

二氧化碳与环氧丙烷的共聚产物-聚丙撑碳酸酯（PPC）已经进入到工业化生产阶段，但是由于其本身玻璃化转变温度通常在30~40℃，且呈无定形态，存在热稳定性差、低温脆性大等问题，大大限制了其应用范围。近期我们的研究工作表明氯化后的PPC表现出了与氯化前迥然不同的性能，其对金属、木材及极性较强的塑料如聚酯、聚氯乙烯等具有优良的浸润性和粘结性，可用于热熔胶、涂料等领域，也可作为增容剂有效提高PPC等与淀粉、天然纤维等合金材料的性能，进而大大拓宽PPC的应用领域。然而，人们对这一全新聚合物材料的结构及其与性能的关系还缺乏基本的认识。本项目针对以下科学问题，即（1）氯化PPC的分子结构及其与氯化工艺的关系；（2）氯化PPC的分子结构与玻璃化转变温度和力、热性能的关系；（3）氯化PPC的分子结构与浸润性、粘结性、成膜性、增容性的关系，开展基础研究，为氯化PPC的应用提供科学依据和技术支持。

以聚丙撑碳酸酯（PPC）为原料通过氯化反应成功在实验室和工业装置上制备了氯化PPC（CPPC），研究了CPPC的结构和性能及其在生物质复合材料、自修复材料等领域的应用，取得了良好效果。（1）在实验室开展了不同条件下PPC的氯化工作，结果表明氯化取代反应主要发生在PPC的-CH3基团上，形成的新基团是-CH2Cl和-CHCl2；（2）通过效率高、无液体的气固相反应，在生产装置上制备了百公斤级CPPC的工业样品，并发现反应温度越高、时间越长、引发剂的加入可使CPPC的氯化度提高，但使分子量和玻璃化温度降低，并且CPPC拉伸强度强度和模量是氯化度和分子量二者竞争的结果；（3）所制备的CPPC在具有良好生物降解性，并对极性表面表现出来了优异粘结性、浸润性、可涂性。 它与包括玉米秸秆在内的生物质复合得到的板材具有力学性能优异、无醛、生物质含量高等特点；（4）制备了以CPPC泡沫为基体材料的具有负温度系数导电效应的功能材料，以及兼具光致形状记忆和自修复能力的CPPC/多壁碳纳米管复合材料。本项目所优化的适用于CPPC大规模工业生产的制备方法以及CPPC所表现出的优异的浸润性、粘结性、可生物降解性等，将对拉动上游PPC的生产，推动包括秸秆在内的生物质利用，解决现有人造板材的甲醛污染问题产生积极影响。