Thermal properties of autoclave and out-of-autoclave carbon fiber-epoxy composites with different fiber weave configurations

Abstract

Thermal expansion, specific heat, diffusivity, and conductivity of carbon fiber-epoxy composites were studied using autoclave and out-of-autoclave prepregs with three different fabric weaves including unidirectional, eight-harness satin, and plain weave. For this purpose, light flash analysis was utilized where the implications of using anisotropic materials were studied. Results indicated that density, thermal expansion, conductivity, and diffusivity were strongly influenced by the fiber configuration of the sample. This phenomenon was attributed to the difference in fiber volume fraction induced by the different weaves of the fabric. Nevertheless, specific heat was similar for all the samples regardless of fabric type or resin formulation. Finally, thermal properties of tetrafluoroethylene release film were presented to analyze the tool-part heat transfer during manufacturing. This release film showed thermal conductivity three times lower than carbon fiber-epoxy samples indicating that the film could be an important contributor to thermal lag between tool and part.