Synthesis and <i>in vitro</i> degradations of low‐molecular‐weight copolyesters composed of <scp>L</scp>‐lactic acid and aromatic hydroxy acids

Abstract

Abstract L ‐lactic acid (LA) was copolycondensed with various aromatic hydroxy acids such as p ‐hydroxybenzoic acid (HBA), p ‐hydroxyphenylacetic acid (HPAA), and p ‐3‐(hydroxyphenyl)propionic acid (HPPA) in the absence of catalysts, in order to investigate the copolymerizability and in vitro degradation. The results of 1 H NMR spectroscopy and gel permeation chromatography (GPC) showed that the reaction proceeds quantitatively, but the molecular weight of the copolyesters is relatively low. The in vitro degradation pattern of copoly(LA/HPPA) was changed into an S‐type from a parabolic‐type with increasing HPPA content in the copolyester, in contrast to only parabolic‐type for both copoly(LA/HBA) and copoly(LA/HPAA).