Research On Polyimide Matrix Resins For Transfer Molding

The main purpose of this paper is to synthesize soluble polyimides (polyisoimides) with high molecular weight that are suitable for Solvent Assiatant Resin Transfer Molding. In this dissertation, the main works are listed as follows:1. Based on the infrared spectroscopy analysis, the optimum conditions for the synthesis of the phenylethynyl-terminated polyisomides model compound are as follows:the imidization time is4h and the heat treatment temperature is60℃.2. According to the optimum conditions, nine kinds of Phenylethynyl end-capped polyisoimides were synthesized by using2,3,3’,4’-biphenyltetracarboxylic dianhydride,3.4’-oxydianiline and4.4’-oxydianiline. The results show that all kinds of polyisoimides exhibit low melt viscosity (resin2<resin1<resin3) and excellent solubility. T5%of the cured resins is higher than500℃, and all of the resins exhibit excellent heat resistance. The glass transition temperatures (Tg) of the polyisoimides resins are high, and the highest Tg is430℃. In addition, the carbon fiber reinforced polyisoimide matrix composites exhibit excellent mechanical properties.3. The different solid contents of polyisoimide resin solutions with DMAc as solvent were prepared. Rheological results proved that the viscosities of many polyisoimide resin solutions were lower (<1Pa.s) and it could be maintained for2h. Moreover, the molecular weight of polyimide resin is improved, which is suitable for Solvent Assiatant Resin Transfer Molding.