Biodegradable Copolyesters of Poly(hexamethylene terephthalate) Containing Bicyclic 2,4:3,5‐Di‐ O ‐methylene‐ d ‐Glucarate Units

A set of copolyesters (PHT x Glux y ) with compositions ranging between 90/10 and 50/50 in addition to the parent homopolyesters poly(hexamethylene terephthalate) (PHT) and PHGlux, are prepared by the melt polycondensation of 1,6‐hexanediol (HD) with mixtures of dimethyl terephthalate (DMT) and dimethyl 2,4:3,5‐di‐ O ‐methylene‐ d ‐glucarate (Glux). The copolyesters haveM ¯ win the 35 000–45 000 g mol −1 range, their microstructure is random, and they start to decompose at a temperature well above 300 °C. Crystallinity of PHT is repressed by copolymerization so that copolyesters containing more than 20% of sugar‐based units are essentially amorphous. On the contrary, PHT x Glux y displays a T g that increases monotonically with composition from 16 °C in PHT up to 73 °C in PHGlux. Compared with PHT, the copolyesters show an accentuated susceptibility to hydrolysis and are sensitive to the action of lipases upon incubation under physiological conditions. The degradability of PHT x Glux y increases with the content in Glux units.