Carbon Dioxide-Based Cross-Linked Poly(hydroxyurethane-urea) Elastomers: Synthesis and Modification Utilizing Pendent Hydroxyl Groups

Poly(hydroxyurethane)s (PHUs) are regarded as one of the most promising nonisocyanate-based polyurethanes, with their improved performance attracting widespread attention. As a type of PHU, poly(hydroxyurethane-urea)s (PHUUs) can effectively broaden the performance range of PHUs, demonstrating high potential for various applications. In this study, cross-linked PHUU elastomers were prepared through aminolysis of cyclic carbonate, using carbon dioxide-based tricyclic carbonate of glycerol (GTC) as the cross-linker, and carbon dioxide-based amino-terminal polyurea oligomer (TTD*/HMDA*) as the chain extender. The cross-linking density and thermal and mechanical properties of the PHUU elastomers could be tailored by controlling the feed ratio of GTC or TTD*/HMDA*. The reprocessability of the PHUUs was also investigated. To further optimize the properties of PHUUs, modified PHUUs with improved cross-linking density were prepared utilizing pendant hydroxyl groups as cross-linking points. Methacrylic acid (MA) was grafted onto the hydroxyl group, and simultaneously, a dense cross-linking network of the modified PHUUs was formed through the polymerization of MA. With the introduction of MA, modified PHUUs showed an increased glass transition temperature and adjustable mechanical properties. The tensile strength, Young’s modulus, and elongation at break of modified PHUUs were in the ranges of 1.19–15.00 MPa, 0.69–95.65 MPa, and 138–687%, respectively. Modified PHUUs exhibited significantly improved tensile strength and Young’s modulus than those of PHUUs. This work provides an option for preparing high-performance or functionalized PHUUs.