Development of Highly Soluble Addition-type Imide Oligomers for Matrix of Carbon Fiber Composite (I): Imide Oligomers Based on Asymmetric Biphenyltetracarboxylic Dianhydride and 9,9-Bis(4-aminophenyl) fluorene

Abstract

Novel highly soluble addition-type imide oligomers were synthesized from 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA), 9,9-bis(4-aminophenyl)fluorene (BAFL), 4,4′-diaminodiphenyl ether (4,4′-ODA), and 4-phenylethynylphthalic anhydride (PEPA) to fabricate carbon fiber-reinforced plastics (CFRP) by routing imide solution prepreg. The imide oligomers were soluble in aprotic polar solvents of more than 35 wt.%. Imide oligomers consisting of less than 50mol% BAFL per total diamine had good processability when using a hot press. The glass transition temperature ( Tg)values of the cured resins were higher than 340°C. The Tg values increased when the BAFL component increased. The 5% weight loss temperatures ( Td5) were higher than 550°C. The elongations-at-break of the BAFL copolymers were less than that of the polymer without BAFL. An imide solution prepreg was prepared from the imide oligomer solution and carbon fibers. Polyimide/carbon fiber composite without voids was fabricated from the imide solution prepreg.