Comparison of adipate and succinate polyesters in thermoplastic polyurethanes

Succinic acid derived from sugar is reportedly going to be an abundant and inexpensive feedstock for polymer synthesis in the near future. This article reports on succinic acid based polyester polyols prepared with butane diol and compares them to polybutylene adipate, a common polyester polyol derived from petrochemicals. Polybutylene succinate diol prepared via standard condensation polymerization techniques was directly comparable to polybutylene adipate diol. Thermoplastic polyurethanes prepared from succinate and adipate based polyols are compared using differential scanning calorimetry, dynamic mechanical spectroscopy, tensile measurements, wide and small angle X-ray scattering, transmission electron microscopy, atomic force microscopy, and abrasion tests. Thermoplastic polyurethanes made using polybutylene succinate exhibited higher glass transition temperatures and more hard-phase to soft-phase interaction than those with polybutylene adipate, presumably due to the higher number of hydrogen bond accepting carbonyls on the succinate soft segment chain. Abrasion resistance of the elastomers was a strong function of the overall hard segment volume and secondarily a function of factors related to the soft segment, with the succinate based thermoplastic polyurethanes showing a slight decrement relative to the adipate elastomers.