Thermal curing of mesophase pitch: An alternative to oxidative stabilisation for the development of carbon–carbon composites

Thermal curing of mesophase pitch was studied as an alternative to oxidative stabilisation for the development of carbon–carbon composites, with the aim of avoiding several problems associated to the oxidative process such as thickness limitations or gradients in the properties of the resultant materials. Carbon fibre preforms densified with the mesophase were submitted to thermal treatments at temperatures between 400 and 475 °C for different periods in order to promote polymerisation and thus avoid exudation of the matrix precursor during carbonisation. Changes induced in the matrix precursor were monitored by thermogravimetric analysis and infrared spectroscopy. The effectiveness of the treatments was evaluated from the porosity of the resultant materials after carbonisation. The highest degree of polymerisation of the matrix precursor was achieved with treatments at 400 °C for 24 h or 475 °C for 5 h, the resultant materials having similar porosity values to those obtained by oxidative stabilisation.