DEVELOPMENT AND CHARACTERIZATION OF HIGH-PERFORMANCE POLYBENZOXAZINE COMPOSITES

To develop high-performance composites with high temperature resistanc e, two ne synthesized polybenzoxazines were successfully cured with ca rbon fiber to obtain composites with 60 vol% fiber, Results from diffe rential scanning calorimetry studies were used to modify the benzoxazi ne monomers to improve processability in terms of melting point and so lubility. The density and void content of these composites were measur ed. Dynamic mechanical tests were performed to determine the glass tra nsition temperature (T-g) and the activation enthalpy of the glass tra nsition process for these two composites. The effect of cure temperatu re on the T-g of the composites was investigated, Thermal characterist ics were studied by means of dynamic mechanical analysis in terms of i sothermal aging, decomposition temperature from thermogravimetric anal ysis, and storage moduli change at high temperatures. Mechanical evalu ations of these composites were conducted by flexural and interlaminar shear tests, The mechanical and thermal properties of these two compo sites exceed bismaleimide composites and compete with polyimide compos ites, while exhibiting easier processability than polyimides.