Hard, tough and fast self-healing thermoplastic polyurethane
Although extensive research efforts have been devoted to the field, it is still a challenge to synthesise hard and tough polymers, which own self-healing ability under mild conditions. Researchers have now fabricated a hard and tough thermoplastic polyurethane (TPU, PCL-HM). A crack of PCL-HM can be quickly healed under mild conditions (50 °C). Comprehensive characterisation results suggest that the Young’s modulus, tensile strength and elongation at break of PCL-HM can reach 76 MPa, 11.8 MPa and 841%, respectively, which is better than most recently reported TPUs.
Great application prospects
PCL-HM prepared with aromatic disulfide bonds as dynamic covalent bonds, polycaprolactone diol (PCL-2000) as soft segment, isophorone diisocyanate (IPDI) and dicyclohexylmethane-4,4′-diisocyanate (HMDI) as hard segment, can quickly recover to 92% of its original tensile strength within 1 h at 50 °C. Due to the better segment movement and looser packing of aromatic disulfide in PCL-HM, the PCL-HM displays better healing properties compared with other types of TPUs prepared during the study. As the reseachers point out, the fast healing properties of PCL-HM under mild conditions endow it with great application prospects in the field of protective coatings.
The study has been published in Progress in Organic Coatings, Volume 159, October 2021.