Construction of Impact-Resistant Polyurethane Supramolecular Elastomers with Superior Mechanical Properties Based on Quadruple Hydrogen Bonds

Abstract

Polyurethane (PU) materials exhibit strong plasticity due to their unique microphase-separated structure. However, dispersing nanofiller-enhanced polyurethane elastomers remains an urgent challenge, and their impact resistance is limited. In this study, the compatibility of hydroxyapatite (HAP) with a PU matrix is improved by grafting ureido-pyrimidinone (UPy) onto HAP nanoparticles. The enhanced interfacial interactions, driven by multiple hydrogen bonds, result in more physically cross-linked networks, alter the microphase-separated structure of the composite PU materials, and effectively improve their mechanical properties and impact resistance. The composite with 2% HAP/UPy demonstrated the best overall performance, with a tensile strength of 44.29 MPa, elongation at break of 1779.88%, high toughness, and impact compression strength of 60 MPa. Notably, its impact resistance exceeds that of PU by a remarkable 6-fold or more. Based on these findings, we elucidate the mechanism behind the improved mechanical and impact resistance properties. This innovative functionalized HAP/PU composite approach shows great potential for enhancing the mechanical properties and impact resistance of PU through better nanofiller compatibility.