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Abstract
The new monomer 1,4‐bis (4‐fluorobenzoyl) naphthalene was synthesized using the Friedel–Crafts acylation reaction of 1,4‐naphthalenedicarboxylic acid chloride with fluorobenzene. Poly(aryl ether ketone) copolymers possessing various compositions of 1,4‐naphthylene and 1,4‐phenylene moieties were prepared by the reaction of hydroquinone (HQ) with 1,4‐bis(4,4′‐fluorobenzoyl) naphthalene (1,4‐BFN) and 4,4′‐difluorobenzophenone (DFB) in the presence of sodium carbonate and potassium carbonate in diphenyl sulfone (DPS). Thermal analyses of the copolymers showed that the glass transition temperature increased, while the melting temperature and 5 wt% loss temperature decreased with the increase of 1,4‐naphthalene moieties. For the copolymer synthesized with the molar fraction of 1,4‐BFN in the difluoro monomers (1,4‐BFN, DFB) being over 0.1, no cold crystallization temperature and melting temperature were detected, indicating that these copolymers are almost amorphous. The crystal structure of the copolymers with the molar fraction of 1,4‐BFN, not being higher than 0.4, is rhombic. The poly(aryl ether ketone)s copolymers were soluble in polar aprotic solvents step by step for the molar fraction of 1,4‐BFN being over 0.4.