PET copolyesters made from a d-mannitol-derived bicyclic diol

Abstract

The carbohydrate-based bicyclic diol 2,4:3,5-di-O-methylene-D-mannitol (Manx) was made to react in the melt with ethylene glycol and dimethyl terephthalate to produce random PE_xManx_yT copolyesters covering the whole range of molar compositions. The copolyesters had weight-average molecular weights in the 33 000–41 000 g mol⁻¹ interval and were thermally stable up to nearly 380 °C. They displayed T_g in the 81 to 137 °C range with values largely increasing with the content in Manx units. Copolyesters containing minor amounts of Manx were semicrystalline whereas those with contents equal to or more than 30% of Manx were amorphous. Stress–strain parameters were affected by composition, increasing tensile strength and elastic modulus and reducing elongation at break when introducing Manx units. These bio-based PET copolyesters showed enhanced susceptibility to hydrolysis.