多孔热塑性聚合物复合材料中的气相演变

Lightweight reinforced thermoplastics composite(LWRT) known as a novel high performance composite started in the 1990s. Differed from the normal fiber reinforced thermoplastics, LWRT has gas pore as one of the essential parts. Unfortunately the formation mechanism and microstructure of gas pore are blurry. In this project, the gas-phase thansfer process will be studied using four essential parts, which are gas pore, fiber bed,matrix and interface for simplifying the LWRT. Based on the multiphase flow of porous medium and mesh scale mechanics of composite, the interaction among the gas, fiber and high viscous melt will be investigated in the heated and compressed fiber bed system. Furthermore, the morphology of gas pore, fiber and matrix will be characterised, the porous microstructure described by suggested parameters systematically. The macro performance of LWRT is determined by its microstructure. Both the macro properties and microstructure are closely related to the multiphase structure of LWRT and multiscale character in manufacturing process, however little knowledge of these is known. In this project, adoptting the method of experiment combined with model, the adjusting and controlling approach of the porous microstructure will be proposed. This will be based on the relationship between porous structure and controled macro factors ,which originates from the intra- and inter-action of pore evolution produced by gas phase flow, fiber bed structure,and matrix impregnation. This projest engages in developing connotation of the material chemical engineering, especially establishing the foundation of pore reinforced polymer materials. Moreover the uniquer pore formation technology provides a new technique for manufacturing lightweight high performance materials, and meets the urgent need for material lightting development.

轻质热塑性复合材料(LWRT)是上世纪90年代出现的新型高性能复合材料，与常规纤维增强热塑性复合材料不同，气相泡孔是LWRT的构成要素，但泡孔形成机制及其微结构不详。本项目将LWRT简化为纤维、基体、泡孔及界面四要素，以气相传递过程为研究对象，依托多孔介质中多相流及细观复合材料力学，探索纤维床中加热、加压条件下气相与纤维及高粘熔体的作用，考察泡孔与纤维、基体的界面形态，量化泡孔微结构。LWRT的宏观性能由其微观结构所决定，但与之密切相关的多相结构及其制备中的多尺度特征认识却有待深入。本项目将采取实验和模型化相结合的方法，从纤维床层结构、气相流动与泡孔演变、基体浸渍润湿等方面建立泡孔微结构与宏观可控因素间的关系，寻求泡孔微结构调控的途径。此研究将拓展材料化学工程学科内涵，建立多孔增强聚合物材料的基础理论，其泡孔形成的独特技术为轻质高性能材料制备提供了新思路，满足材料轻量化发展的迫切需要。

多孔热塑性聚合物复合材料（LWRT）依靠浸渍膨化技术构建气相泡孔结构，并通过泡孔结构设计赋予良好的刚性与韧性及物理性能，为高性能、功能梯度材料的构造及其轻量化提供新的途径。其性能取决于基体、增强体及其适宜界面作用下的泡孔微结构；并可通过宏观结构参数与工艺调控气相演变，以构建适宜的泡孔微结构达到性能最佳化。.本项目采用实验研究与数值模拟相结合的方法，在泡孔形成与排除机理认识的基础上，研究了纤维床层多尺度结构、基体粘度、浸渍压力等因素对气相迁移演变浸渍动力学的影响。根据泡孔形貌及其影响因素分析，确认构成其微结构所需的线面体三种界面结构形态，并通过纤维含量、长度、针刺密度、基体相容改性、纤维表面处理、片材面密度及厚度等宏观参数与工艺进行调控，获得泡孔微结构的量化参数。形成了以泡孔微结构的构建为核心，利用加热加压熔融浸渍过程中纤维网络结构的弹性储能进行受限释放的调控机制。以基体的相容改性与纤维表面处理的界面结构设计，以及纤维床层结构的参数调节，通过LWRT面密度及成型厚度的变化获得复合材料所需的刚度、韧性、动态力学性能与物理性能。.气相泡孔形成及其迁移演变机制与调控策略的运用，不仅可以通过泡孔微结构设计实现多孔材料的轻量化与刚韧性能的协同，还可对致密型热塑性复合材料进行结构设计。如碳纤维床层结构及其与基体树脂的相容改性界面结构设计、聚碳酸酯/玻纤复合材料的浸渍结构优化、多尺度长玻纤/单向连续纤维层合复合材料结构增韧设计、高性能化强韧协同的分布层合结构设计，都验证了微结构-制造过程-性能与宏观可控参数的内在联系及其可调控性。.本研究涉及多孔热塑性复合材料微结构制造过程依赖性的关键影响因素调控方法，拓展了材料化学工程科学的内涵。研究结果为多孔增强聚合物材料基础理论提供了数据支撑，其独特的泡孔形成技术为轻质高性能材料的规模化低成本制造提供了新思路，满足了材料轻量化发展的迫切需要。