Coating carbon fibres with hybrid polymers for use at high temperatures

A thermal resistance coating of different high temperature resistance polymers, e.g. polysilazane and polysiloxane was applied to a carbon roving by a continuous dip coating method. Improved mechanical and thermal resistance properties of the coated carbon roving were evaluated by thermogravimetric analysis and tensile property testing under thermal stress. Investigation of the mechanical properties of coated carbon roving revealed a significant increase in their breaking strength, which amounted to more than 50% as compared to uncoated roving. The thermal stability as well as the oxidation protection of the coated sample in ambient air at temperatures up to 800℃ was much higher than that of the control sample. Topographical phenomena occurring due to the coating on the microscale were examined by scanning electron microscopy and energy dispersive X-ray analysis. The surface energy and the adhesion property of the coated substrate were determined by measuring the contact angle.