基于悬浮聚合与超临界CO2可控制备PMI前驱体功能微孔珠粒及其模内发泡研究

聚甲基丙烯酰亚胺（PMI）泡沫是当今耐热性和强度最优异的硬质结构泡沫。亟待解决现有制备技术中大分子链序列结构调控性差、容易爆聚、难以实现阻燃和导电、无法成型复杂形状制品等难题。为此，本项目提出一种PMI泡沫制备新方法，拟通过自由基本体预聚合和水相悬浮聚合的调控，制备出粒径可控的球形PMI前驱体功能珠粒。功能珠粒先经过超临界CO2/低沸点溶剂协同发泡成为前驱体微孔珠粒，微孔珠粒再经水蒸气模内二次发泡成型为PMI功能泡沫，以便解决高发泡倍率PMI泡沫的泡孔稳定性难题。通过调控反应程度和优化单体的分子结构抑制油相组分的水溶性以及共聚物在油相中的沉淀，揭示气体在分子间作用力强的前驱体中传质机制，建立非均匀膨胀微孔珠粒表界面相互作用力提升方法等科学问题，厘清材料制备-结构调控-宏观性能三者之间的构-效关系，突破现有PMI泡沫制备技术的瓶颈，为发展高性能结构功能一体化共聚物泡沫提供理论基础和实验依据。

Polymethacrylimide (PMI) foam is the best rigid structure foam with outstanding thermal resistance and strength. However, several main problems of poor regulation performance of macromolecular chain structure, easy explosive polymerization, difficulty to achieve flame retardant and conductivity, and inability to form complex shaped products are main obstacles for PMI foams. This project proposed a new strategy for the synthesis and preparation of PMI foams. The spherical PMI precursor functional beads with controllable particle size are prepared through the regulation of free radical bulk prepolymerization and aqueous suspension polymerization. Then, a two-step foaming processing is consisted of the first microcellular beads preparation by the synergistically foamed with supercritical CO2/low boiling point solvents. The microcellular beads are then foamed into a PMI functional foams by the secondary foaming using steam-chest molding process so as to improve the expansion rate and the bubble stability. By studying the mechanism of inhibiting the water solubility of oil phase components and the precipitation of copolymers in oil phase, promoting the mass transfer ability of gas molecules in the precursor macromolecular system with strong intermolecular interaction, increasing the interfacial force of non-uniform expanded microcellular beads, this project is aiming to reveal the structure-properties relationship between material preparation, structural regulation and macro-performance, and to further overcome the bottlenecks of the existing PMI foam preparation technology. This project would provide the theoretical basis and experimental basis for developing high performance structure-function integrated copolymer foam.