反应性梳形聚合物的分子设计及其在反应性共混中的应用

Reactive compatibilization of two immiscible polymer blend components at the nanometer scale is an efficient route to produce high performance materials, which have a synergistic combination of properties that surpasses those of the individual polymer components. Although several types of compatibilizers like block and graft copolymers have been applied in reactive blending, the relationships between the structural parameters of the copolymers and their compatibilization efficiency has been hardly investigated. In this research protocol, we would like to design and synthesize a reactive comb-like polymers by copolymerization of methyl methacrylate (MMA), glycidyl methacrylate (GMA) with poly(methylmethacrylate) macromonomer (MMA-PMMA). The latter was prepared by polymerization of methyl methacrylate in the presence of thioglycolic acid as a transfer agent, followed by reaction with glycidyl methacrylate. We decided to do a systematic research to reveal the influence of structural parameters, such as length of side chains and backbone, side chain density and distribution and fraction of glycidyl unit on the compatibilization efficiency of immiscible polymer blend systems. This protocol will guide us to design and synthesize more effective compatibilizers and to produce new structural and functional materials by reactive blending.

通过反应性增容提高不相容高分子共混材料的相容性是制备高性能聚合物共混材料的有效途径，但人们对于反应性相容剂分子结构设计的研究还很不充分。本项目首先使用大分子单体技术，合成甲基丙烯酸甲酯型大分子单体（MMA-PMMA），再将合成的大分子单体与甲基丙烯酸甲酯（MMA），甲基丙烯酸缩水甘油酯（GMA）共聚，从而制备出分子结构可控（包括支链长度、支链间距、环氧基团含量等）的含反应基团的梳形聚合物。然后用具有不同分子结构的反应性梳形聚合物作为增容剂，研究其对于不相容高分子聚合物的增容效果，从而定量的揭示增容剂支链长度、反应性基团密度等分子结构参数对其在反应性共混中的增容效果。这一研究不但能合成新型高效增容剂，制备高性能高分子共混材料，而且将从理论上指导反应性增容剂的合成，促进高分子材料反应性共混改性的研究与应用，具有重要的学术意义和工业应用价值。

对不相容共混体系进行反应性增容是制备高性能材料的一条有效途径。我们设计将甲基丙烯酸甲酯同甲基丙烯酸缩水甘油酯以及甲基丙烯酸甲酯大分子单体共聚，从而合成了一种反应性的梳形分子。研究发现，该分子能够高效增容很多不相容共混体系。例如，聚乳酸/聚偏氟乙烯是典型的不相容共混体系，聚偏氟乙烯以不规则粒子分布于聚乳酸基体中。当添加3wt%的梳形分子时，聚偏氟乙烯相尺寸变小且更为均一，同时材料的韧性和模量均得到了显著的提高。我们将梳形分子的高效增容归因于共混过程中，它能稳定的存在于两相界面上，从而减小分散相尺寸，提高界面粘合力，而不是被拉到其中一相中形成胶束。