Preparation of mechanically tunable non-isocyanate polyurethane based on thiol-ene click reaction and amine structure

Non-isocyanate polyurethane (NIPU) is one of the hot spots in the scientific research of polyurethane. In this work, mechanically regulable NIPU were prepared by ring-opening polymerization of cyclic carbonates via diamines. Cyclocarbonates with different functionalities were firstly synthesized by thiol-ene click reaction, which was characterized through nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The controllable mechanical performance of NIPU films was obtained by the structure of the diamines and the functionality of the thiol groups. The results of swelling and differential scanning calorimetry experiments suggested that the control of functionality and reactivity endowed the material with an adjustable crosslinking density. The Young's modulus of the material could be regulated from 51.3 to 765.1 MPa. Furthermore, the studied films also showed good thermal stability. The present study provides some guidance for the preparation of non-isocyanate polyurethane coatings for different application scenarios.