Synthesis and characterization of eco-friendly chitosan-based waterborne polyurethanes and their ultraviolet degradation properties

This study synthesized chitosan-based waterborne polyurethane copolymers. Polyurethane prepolymers were prepared using isophorone diisocyanate, polytetramethylene ether glycol, and N-methyl diethanolamine, and chitosan was introduced during chain extension. With its rigid cyclic structure and multiple reactive groups, chitosan replaced traditional butanediol as a chain extender, greatly enhancing the mechanical properties and thermal stability of the final product. Additionally, highly deacetylated chitosan exhibited higher reactivity toward the terminal isocyanate group of the polyurethane prepolymers, leading to the formation of a highly dense cross-linked network structure. Finally, the chitosan/waterborne polyurethane composites were subjected to an ultraviolet-accelerated degradation test in order to elucidate their degradation mechanism. Gel permeation chromatography was used to study changes in the molecular weights of the composites during photodegradation. The findings of this study highlight the application value of eco-friendly materials and the significance of green chemistry.