Abstract: Production of composites having increased strength, particularly at elevated temperature, heat resistance and ablative properties, while maintaining low weight, by a process which comprises impregnating fibrous reinforcement, such as a woven fabric of graphite yarns, with a resin, e.g., a phenolic resin, curing the resin to yield a fiber-resin composite, pyrolyzing such composite to convert the resin to a porous carbonaceous matrix, reimpregnating the porous fiber-carbon composite with additional resin, such as a phenolic resin, to fill the pores of the matrix, and curing the reimpregnating resin. The resulting fiber reinforcement-resin matrix-carbon matrix (i.e., bimatrix) composites are particularly useful and valuable as reinforced plastic aerospace components requiring strength at high temperatures and having improved ablative properties.

Abstract: Production of composites having increased strength, particularly at elevated temperature, heat resistance and ablative properties, while maintaining low weight, by a process which comprises impregnating fibrous reinforcement, such as a woven fabric of graphite yarns, with a resin, e.g., a phenolic resin, curing the resin to yield a fiber-resin composite, pyrolyzing such composite to convert the resin to a porous carbonaceous matrix, reimpregnating the porous fiber-carbon composite with additional resin, such as a phenolic resin, to fill the pores of the matrix, and curing the reimpregnating resin. The resulting fiber reinforcement-resin matrix-carbon matrix (i.e., bimatrix) composites are particularly useful and valuable as reinforced plastic aerospace components requiring strength at high temperatures and having improved ablative properties.