A sheet comprising a mixture of poly (m-phenylene isophthalamide) and a copolymer prepared from (6)-amino-2-(p-aminophenyl) benzimidazole and a sheet comprising fibrid

摘要

This invention relates to a sheet comprising fibers and fibrids wherein either comprises a mixture of at least a first polymer and a second polymer; the first polymer derived from the reaction of one or more amine monomers and a plurality of acid monomers, wherein the one or more amine monomers includes at least 60 mole percent 5(6)-amino-2-(p-aminophenyl)benzimidazole, based on the total amount of amine monomers; and the plurality of acid monomers include those having a structure of Cl—CO—Ar1—CO—Cl & Cl—CO—Ar2—CO—Cl wherein Ar1 is an aromatic group having para-oriented linkages and Ar2 is an aromatic group having meta-oriented linkages, and wherein the plurality of acid monomers has at least 50 mole percent of the monomer containing aromatic group Ar2; and the second polymer derived from the reaction of metaphenylene diamine and isophthaloyl chloride.