Research On Heat Resistant Resins For Advanced Composites Based On Aerospace Application

The work was aimed to study the resins for advanced composites based on aerospace applications, especially for the heat resistant properties. The heat resistant epoxy resins with new structure were designed and a modified bismaleimide resin for pultrusion process was also prepared. The structures of the molecular chain of the resins were designed and the ratio of the rigid group could be controlled by reaction process conditions. A new composite Z-pin was also prepared by pultrusion process from carbon fiber and the modified bismaleimide resin, which could increase interlaminar strength of the composite laminates a lot.By using diglycidyl ether of bisphenol A liquid epoxy resin with lower molecular weight E-54 and solid bisphenol A as raw materials. Triphenylphosphine, ethyltriphenylphosphonium acetate, ethyltriphenylphosphonium bromide, ethyltriphenylphosphonium chloride and tetraphenylphosphonium bromide were selected to be used as catalyst in the specific synthesis experiments, the optimal catalyst could be found by observing the phenomena of each reaction and the appearance of the products. The results showed that ethyltriphenylphosphonium bromide catalyst has a better exhibition and the solid epoxy resin was successfully synthesized. The relationship of the reaction conversion toward the ratio of the raw materials and the temperature or time was studied. A novel heat resistant epoxy resin bearing biphenyl structure was prepared using liquid epoxy resin and 4,4'-biphenol as raw materials, tetraphenylphosphonium bromide as catalyst. The glass transition temperature of cured resin was increased by 15.2℃when using 4,4 diaminodiphenyl methane as curing agent.A kind of heat resistant epoxy resin containing naphthyl group was designed and synthesized by the Advancement method. The relationship between the molecular weight and the distribution of the product and the reaction condition was studied and the curing kinetic parameters were estimated by the Kissingger Model. When the resins were added into carbon fiber reinforced composites, the glass transition temperature of the materials were increased evidently.Modified bismaleimide resin for composites pultrusion process was synthesized from the prepolymerization of 4,4-diphenyl methane bismaleimide and diallyl bisphenol A. The heat resistant carbon fiber reinforced Z-pin composites was prepared from the resin and the mechanical properties of the composites were carefully evaluated.