Aliphatic polyesters and their copolymers synthesized through direct condensation polymerization

Abstract Copolymers of lactic acid and the other hydroxyacid, such as glycolic acid and 6-hydroxyhexanoic acid, were prepared in an organic solvent through the direct condensation. Glass-transition temperatures and melting points of these polymers are slightly different from those of polymers obtained by the ring-opening polymerization process. The other type polyesters from dicar☐ylic acids and diols that have molecular weights of up to 300 000 were also prepared by the same method. The high-molecular-weight polyester obtained can be processed into films and molded products of a sufficient strength and toughness. Copolymers synthesized from the reaction of polylactic acid and the other aliphatic polyesters or cellulose derivative were also discussed.