PROCESSIBLE POLY(ARYLENE ETHER KETONE)S THAT CAN BE CROSS-LINKED TO HIGH-PERFORMANCE NETWORKS

High molecular weight copolymers containing 2,5-bis(4-fluorobenzoyl)benzocyclobutene (BFBCB), 1,4-bis(4-fluorobenzoyl)benzene (BFB), and 4,4-isopropylidenediphenol have been synthesized by solution polycondensation. Soluble, amorphous polymers were obtained and no evidence of cross-linking occurred during the polymerization reaction, provided that the temperature was maintained below 150-degrees-C. The polymers were characterized by gel permeation chromatography and by H-1 and C-13 NMR. The copolymers can be cross-linked well above their glass transition temperature by brief treatment in nitrogen at 400-degrees-C. The cross-linking reaction has been monitored by differential scanning calorimetry, which shows that the heat of the reaction is proportional to the BCB content. The resulting networks are insoluble in all solvents including concentrated sulfuric acid. Thermogravimetric analysis shows that no significant mass loss accompanies the cross-linking reaction.