松脂基热可逆自修复聚氨酯材料的结构设计、制备及修复机理研究

Oleoresin is mainly obtained from tapping trees of the genus Pinus, and it is an important and abundantly available natural chemical in China. Turpentine is the volatile oil distilled from oleoresin, and the solid material left behind after distillation is known as rosin. Both products are used in a wide variety of applications, but their high-value utilization still remains at a relatively low level. It is necessary to explore other higher value products. It is known that rosin- and turpentine-based polyurethanes exhibit excellent mechanical properties and thermal stability. So, in this project, rosin- and turpentine-based linear polyurethanes with high self-healing effective and glass transition temperature will be prepared by a two-step method, while the self-healing mechanism is introduced through the thermoreversible Diels-Alder (DA) bonds. The objectives of this project include: 1) study the kinetics of DA monomers reaction and polyurethane polymerization to obtain optimum reaction temperature and activation energy; 2) investigate effects of the thermoreversible DA reactions on thermal behavior, chemical structure shift, molecular weight distribution; 3) investigate the changes of surface morphology and mechanical properties after damage repair; 4) discuss the factors of self-healing performance and efficiency, meanwhile explore the self-healing mechanism. This research will make important contributions to the knowledge and technology of rosin-based polymer materials. It may also provide a certain guideline for future development of biomass-based intelligent self-healing polymer materials.

我国林业特色资源松脂的应用以简单加工为主，高附加值利用率低，开辟高端应用新领域迫在眉睫；本项目依据松香和松节油制备的聚氨酯材料具有优良力学性能和热稳定性的特点，首次采用两步法在松脂基聚氨酯结构上引入热可逆Diels-Alder (DA)键制备具有高自修复率和高玻璃化转变温度的线型聚氨酯材料；在研究单体DA反应动力学基础上分析材料的聚合动力学，获得最佳反应温度和活化能；着重考察自修复材料发生DA和逆DA反应时吸放热行为，结构化学位移、分子量分布等热可逆性能的变化；通过受损材料修复后的表面情况和力学性能变化考察自修复性能和效率的影响因素，揭示自修复机理；本项目研究将为合理、高效、高附加值利用松脂资源奠定坚实的理论和应用基础，对开发生物质智能自修复高分子材料具有重要指导作用。

我国松香等林业特色资源的应用以简单加工为主，高附加值利用率低，开辟高端应用新领域迫在眉睫。聚氨酯等高分子材料具有良好的机械、加工性能和热稳定性，广泛应用于胶黏剂、涂料、弹性体等领域。但在加工和使用过程中，不可避免地产生一定程度的损伤，导致使用性能下降。本项目面向问题和需求导向，模仿生物体损伤自修复机理，进行结构设计对生物基聚氨酯等高分子材料内部微裂纹进行自主修复，以提高材料使用性能和降低成本。项目组以松香、植物油等及生物质为原料，完成了多种生物基功能单体、生物基自修复聚氨酯等高分子材料的结构设计制备，对生物基功能单体、生物基自修复聚氨酯材料的物理化学性能和结构进行了分析表征。重点通过引入多重氢键、亚胺键、氨酯键、DA键等多种可逆共价非共价键构建动态可逆共价网络高分子材料，并结合分子动力学（MD）模拟证明范德华力随温度变化规律及自修复机理，赋予了生物基聚氨酯等高分子材料自修复、形状记忆、可回收、可重塑、可降解等功能特性；明确了松香等生物质分子特有结构及反应活性对动态可逆共价网络和自修复高分子材料性能的作用机制及材料力学性能和热稳定性与自修复效率的相互作用规律。实现了以松香、植物油等生物质资源作为原料应用于自修复聚氨酯等功能高分子材料的可控制备，本项目研究将为高效、高附加值利用香等林产资源提供技术支撑，对开发生物基功能自修复高分子材料具有重要指导作用。相关内容发表论文（包括已接受待发表）14篇（第一标注7篇、第二标注7篇），其中SCI收录9篇，EI收录1篇，中文核心4篇；申请国家发明专利6件，协助培养博士研究生2名、硕士研究生3名。