Influence of carbon fibre treatment and filler addition on porosity and structure change of carbon fibres reinforced phenolic matrix composites during carbonization

The transformation during pyrolysis of ex-cellulose carbon fibres/phenolic matrix 2D composites is investigated. The amount and the dimensions of pores and micro-cracks created after heat treatment are characterized and described from 600 °C (resin pyrolysed matrix) to 1,000 °C (carbonized matrix). Characterization of samples was performed using mercury intrusion porosimetry at different stages of thermal treatment. Three different composites were prepared in order to study the influence of fibre surface properties and the role of carbon filler addition in matrix, on the porosity emergence. Inter-laminar shear strengths of these materials were recorded. On the investigated materials, the lowest fibre/matrix bonding is found to preserve material cohesion by promoting interfacial debonding and thus limiting consequences of shrinkage during matrix carbonization.