POLY (ETHYLENE TEREPHTHALATE) COPOLYMERS WITH HALOGENATED TEREPHTHALIC ACIDS

Abstract

Poly (ethylene terephthalate) copolymers were prepared by substitution up to 40 mol% of diacid comonomers: 2, 5-dichloroterephthalic acid (TCl2) and 2, 5-dibromoterephthalic acid (TBr2). ηsp/C of the copolymers does not depend on the comonomer content. Melting point depression shows that copolymers with TCl2 and TBr2 are non-isomorphous. Glass transition temperature shows a minimum at 30mol% copolymer. The crystallization rate followed by the change of density decreases with increasing comonomer content. Solubility increases by the copolymerization. The resistance to alkali-hydrolysis increases a little for 10mol% copolymer and decreases for more halogen-containing copolymers. Flame-retardancy was estimated by heating the copolymers for 1h at 350°C in air. Weight loss of halogen atoms in the copolymers increases, and residue except halogen atoms in the copolymers decreases with increasing comonomer content. These variations with increasing comonomer content were more pronounced for copolymers with TBr2 than for those with TCl2.