Effect of prepreg resin composition on honeycomb core crush

摘要

Past research has shown that the level of core crush experineced in the autoclave manufacture of honeycomb cored composite structures varieswidely betwen prepreg systems. This differing manufacturing behavior has been attributed to differences in prepreg frictional resistance at procesisng conditions. At similar levels of impregnation, elastomer modified epoxy-based prepreg systems show consistently higher levels of core crush than standard high flow prepregs. Therefore, the role of resin composition in honeycomb core crush was investigated to determine the feasibility of development of model prepregs with varying elastomer concentration. The kinetics of the reactive carboxyl-epoxide adduction were also investigated. The core crush tendencies of the model prepregs were evaluated through the measurement of prepreg frictional resistance. It was found that prepreg frictional resistance decreased with increaisng elastomer concentration. These differences were related to differences in the viscosity and elasticity of the impregnated resins as determined through oscillatory rheology. It is anticipated that these differences would result in an increased incidence of core crush.