Next-generation bio-polyurethanes with modified hard segments: Synthesis, chemical structure, thermal and mechanical behavior

Abstract

Modification of the hard segment structure in polyurethanes using isocyanate mixtures has emerged as one of the most effective strategies for developing new materials with enhanced properties and a high content of bio-based carbon. In this work, next-generation sustainable thermoplastic polyurethane elastomers (bio-TPUs) were synthesized using aliphatic isocyanate mixtures based on bio-derived diisocyanates Tolonate™ X FLO 100 and dimeryl diisocyanate (DDI) alongside hexamethylene diisocyanate (HDI). Poly(trimethylene ether) glycol (PO3G) and bio-based 1,3-propanediol served as renewable hydroxyl-terminated components. The bio-TPUs were prepared using the common ‘one-shot’ method. The resulting materials were analyzed to assess phase separation, morphology, as well as mechanical, thermal and thermomechanical properties. The results confirm the significant influence of the type of diisocyanate mixture on the properties of bio-TPU, improving their thermal stability (up to 300 °C) and reducing the melting temperature to 140 °C, which makes them suitable for low-temperature processing.