热固性异酰亚胺树脂及复合材料的研究

To match the material property requirements in the rapidly developing aerospace industry, it is of scientific and practical significance to develop resin matrix composites with high thermal resistance and excellent overall properties. In order to simultaneously improve the resin processability and material properties of cured composites, we propose to design and synthesize thermosetting isoimide resins with high solubility in low boiling point solvents. Through the investigation of their crosslinking and imidization behavior, the curing parameters will be determined. Then the thermosetting polyimides and composites will be characterized in terms of thermo-oxidative stability, glass transition temperature, and mechanical properties. Due to their unique asymmetric architectures, isoimide resins showed enhanced solubility, low melting temperatures, and reduced complex viscosity compared to their imide analogues based on the same monomers. Furthermore, isomide can be thermally converted to imide without the release of water or other volatiles. These characteristics are highly desired to overcome several limitations in thermosetting polyimides, including poor processability, high composite void content, brittleness, as well as low thermal properties. Hopefully, isoimide resins can provide a combination of high processability and excellent material properties. The accomplishment of this project will lead to the establishment of the structure-property relationship in thermosetting isoimide resins. This project will also provide scientific fundamentals and technical database for isomide resins and resulted composites.

随着航空航天等领域对材料性能要求的不断提高，开发耐高温高性能树脂基复合材料具有重大的科学意义及应用前景。为了同时提高聚酰亚胺树脂的工艺性和固化物性质，本项目拟设计合成一系列在低沸点溶剂中高可溶的热固性异酰亚胺树脂，通过研究异酰亚胺树脂固化及亚胺化行为，确定树脂的固化条件，并系统评价树脂的性质及固化后树脂及复合材料材料的性能。异酰亚胺树脂由于其特有的非对称结构，与基于相同的单体酰亚胺树脂相比，具有溶解度高、熔融温度低和熔体粘度低等优点，同时在高温条件下可转化为酰亚胺且无小分子放出，有望解决困扰热固性聚酰亚胺树脂领域的工艺性差、复合材料孔隙率高、韧性差、耐温等级尚待提高等难题，实现树脂工艺性与复合材料高性能化的统一。通过本项目的实施，可以建立异酰亚胺树脂结构同其加工性以及固化后高分子及复合材料性能之间的关系，为这类材料的推广应用积累实验数据，奠定科学基础。

随着航空航天等领域对材料性能要求的不断提高，开发耐高温高性能树脂基复合材料具有重大的科学意义及应用前景。为解决热固性聚酰亚胺树脂工艺性同耐热等级矛盾的难题，本项目以3,4‘-联苯二酐和3,4’-二苯醚二酐为单体，苯乙炔苯酐为封端剂，三氟乙酸酐为脱水剂，设计合成了一系列异酰亚胺树脂，系统评价了树脂的溶解性、亚胺化行为、固化行为、工艺性、热性能和机械性能；利用上述树脂制备了石英纤维和碳纤维增强复合材料，并评价了复合材料的高低温力学性能。研究结果表明，由于其特有的非对称结构，异酰亚胺树脂比采用相同单体的酰亚胺树脂具有更好的溶解性和更低的熔体粘度，单体选择范围更广，可采用刚性更强的二酐和二胺单体，因此纯树脂固化物的玻璃化温度可达500℃以上，复合材料的长期使用温度可达450℃，短期使用温度可达550℃，从而实现了树脂工艺性同复合材料耐热性的统一。通过本项目的实施，建立了异酰亚胺树脂结构与性能之间的关系，确立复合材料的成型工艺并系统评价了其性能，为这类材料的应用积累了丰富的数据，打下了坚实的理论基础。在此基础上，项目组研制了多种异酰亚胺树脂，并在导弹结构件和功能件上实现了具体应用。