PROCESSING AND CHARACTERIZATION OF CARBON-FIBER-REINFORCED POLYNAPHTHOXAZINE COMPOSITE

In order to attain a high-temperature resistant composite with good pe rformance as well as processability, a polynaphthoxazine composite wit h 60% by volume of carbon fibre has been successfully developed. The n aphthoxazine monomer was modified to obtain lower melting point and hi gher solubility for improved processability. The density and void cont ent of this composite were measured at room temperature. The T-g and t he activation enthalpy of the glass transition process were measured b y dynamic mechanical analysis, and the effect of cure temperature on t he T-g of the composite was studied. The thermal characteristics of th is composite were studied in terms of the weight loss after isothermal ageing, the decomposition temperature from thermogravimetric analysis , and the change in dynamic storage moduli at high temperatures. Flexu ral and interlaminar shear tests were performed to evaluate the mechan ical properties of this composite. A good balance between strength and toughness of this composite was achieved. A very high char yield of 9 0% was gained after carbonization in a nitrogen atmosphere. This polyn aphthoxazine composite compares favourably with the bismaleimide compo sites in terms of mechanical properties and thermal stabilities.