Synthesis and Properties of Poly(aryl ether ketone) Copolymers Containing 2,7-Naphthalene Moieties

Poly(aryl ether ketone) copolymers containing 2, 7-naphthylene and hydroquinone (HQ) moieties with various compositions were prepared by the reaction of 4,4′-difluorobenzophenone (DFB) 2,7-naphthylene and hydroquinone in the presence of sodium carbonate and potassium carbonate (19: 1, mass ratio) in diphenyl sulfone (DPS). The thermal analysis results of the copolymers show that the glass transition temperatures (Tgs) increase, while the melting temperatures (Tm) and the 5.0% weight loss temperatures (Td) decrease with the increase of the 2,7-naphthalene moieties. For the copolymers synthesized at a molar fraction of 2,7-naphthalene in the difluoro monomers being over 0. 30, no peaks corresponding to the cold crystallization temperature and the melting temperature could be detected, indicating that these copolymers are almost amorphous. The crystal structures of the copolymers with a molar fraction of 2,7-naphthalene being less than 0. 30 are rhombic.