易成型高强度树脂基泡沫炭材料的制备及孔泡形成新机理

Carbon foam, a kind of porous carbon material with interconnected three-dimensional microstructure, possesses special performances, such as low density, high porosity, high temperature tolerance and excellent corrosion resistance, therefore, has attracted increasing attention in many fields ranging from aeronautics, astronautics, chemicals, electronics, energy, environmental protection to catalysis. However, its poor mechanical strength (the main drawback), difficult moulding, high cost, complex technology and other issues in the production of carbon foam greatly restricts its further development and application. In this project, carbon foam with high mechanical strength was directly prepared by atmospheric pressure pyrolysis of a thermosetting allyl compound/bismaleimide copolymer resin product, which was prepared by performing a series of procedures including prepolymerization, bubble removal, casting and curing. Pyrolysis behavior of the thermosetting copolymer resin was studied to reveal both the self-bubbling mechanism and the bubble formation and development of carbon foam. Moreover, influence of preparation and carbonization processes of the thermosetting copolymer resin on the microstructures, mechanical properties and thermophysical properties of resultant carbon foam was investigated to ascertain the formation of structural defects in the carbon foam and thus put forward the control technology and theory of its structure and properties. The results of this project are of great importance and value in enriching the theory of bubble formation of carbon foam as well as promoting the progress of its preparation technology.

泡沫炭是一种三维网状结构的多孔炭材料，具有密度小、孔隙率高、吸震性好、耐高温、耐腐蚀等特性，在航空、航天、化工、电子、能源、环保、催化等领域具有广阔的应用前景。然而，泡沫炭的主要缺点是力学性能差，在制备过程中还存在难以直接复杂成型、成本高、工艺复杂等问题，这极大制约了其进一步发展和应用。本项目提出以烯丙基化合物和双马来酰亚胺为原料，经预聚、脱气泡、浇注、固化成型等工艺制备热固性烯丙基化合物/双马来酰亚胺共聚树脂样件，然后常压热解这种树脂样件直接制备高强度泡沫炭制品。通过研究该热固性共聚树脂的热解行为，揭示其热解自发泡机理与孔泡形成演变规律；通过探讨该热固性共聚树脂制备和炭化工艺对最终泡沫炭的微观结构、力学性能和热物理性能的影响规律，阐明泡沫炭结构缺陷产生的原因，并提出其结构和性能的控制工艺及理论。本项目研究对于丰富泡沫炭孔泡形成理论、促进泡沫炭制备技术的进步具有重要的学术意义和应用价值。

泡沫炭作为一种具有轻质、耐腐蚀、耐高温、热膨胀系数低等性能的三维网状多孔炭材料，广泛应用于航空、航天、化工、电子、能源、环保、催化等诸多领域。针对目前泡沫炭存在力学性能差、制备成本高、工序复杂、难以复杂成型等问题，本项目以烯丙基化合物和双马来酰亚胺（BMI）为原料，经预聚、脱气泡、浇注、固化成型等工艺制备热固性烯丙基化合物/双马来酰亚胺共聚树脂，然后常压热解这种树脂样件直接制备高强度泡沫炭制品。采用SEM、FT-IR、TG-DTG、Raman、元素分析等对烯丙基化合物/双马来酰亚胺共聚树脂的热解行为进行研究。采用SEM、XRD、激光热导仪、电子万能试验机等对采用烯丙基化合物/双马来酰亚胺共聚树脂制备的泡沫炭的结构与性能进行研究。研究表明，烯丙基化合物/双马来酰亚胺共聚树脂具有常压自发泡的特性。随着BMI比例的增加, 其孔径和孔隙率逐渐减小，但是力学性能、导电率、导热率、体积密度及残炭率均有所提高。当烯丙基COPNA树脂与BMI的质量比从1:0.8增加到1:1.1，其压缩强度由0.9MPa提高到2.4MPa，导电率从4.3S/cm增加到10S/cm，导热率由0.31W/m•K增加到0.44W/m•K，体积密度由0.18g/cm3升高到0.25g/cm3，残炭率由34.21%提高到39.26%，但是其孔隙率由91.4%降低到80.2%。高温处理对泡沫炭结构与性能有着较大的影响,其石墨化程度提高。当热处理温度从900ºC升高到2400ºC时，其压缩强度由2.4MPa提高到2.8MPa，导热率0.44W/m•K增加到0.54W/m•K，同时其体积密度由0.25g/cm3上升到0.26g/cm3，孔隙率也由80.2%升高为85.8%。本项目研究对于丰富泡沫炭孔泡形成理论、促进泡沫炭制备技术进步具有重要的学术意义和应用价值。