Thermally Healable Polyurethane Elastomers Based on Biomass Polyester Polyol from Isosorbide and Dimer Fatty Acid

A fully bio-based polyester polyol based on isosorbide (ISB) and dimer fatty acid (DA) was synthesized through esterification. An ISB-based polyester polyol (DIS) was developed to synthesize a bio-based polyurethane elastomer (PUE) with enhanced mechanical and self-healing properties. The rigid bicyclic structure of ISB improved tensile properties, while the urethane bonds formed between the hydroxyl groups in ISB and isocyanate exhibited reversible characteristics at elevated temperatures, significantly enhancing the self-healing performance of DIS-based PUE compared to the control PUE (self-healing efficiency: 98% for DIS-based PUE vs. 65% for control PUE). The dynamic mechanical and rheological properties of DIS-based PUE were investigated to confirm their relationship with self-healing performance. The DIS-based PUE, featuring reversible urethane bonds, demonstrated rapid stress relaxation and maintained constant normal stress under external stimuli, contributing to its improved self-healing capabilities. Thus, ISB can be regarded as a promising bio-resource for synthesizing bio-based polyester polyols and, consequently, PUE with superior mechanical and self-healing properties.