Polyurethane–urea coatings derived from UV-cured polyurethane–urea acrylate transition coatings for enhanced resistance to chemical warfare agent simulants

Enhancing both the protective and mechanical properties of chemical-resistant coatings is a challenging task. In this study, ultraviolet (UV) cured polyurethane–urea acrylate (PUUA) containing hindered urea groups were prepared to function as a transitional coating during periods of non-use. This transitional coating offers both flexibility and impact resistance. Upon heat treatment, the PUUA network shifts from the transitional state to a defensive state, forming a polyurethane–urea (PUU) network with improved resistance to 2-chloroethyl sulfide (CEES), a mustard gas simulant. The effects of different heat curing agents (diamines) on the PUUs were investigated in terms of physical and chemical structures, curing mechanism, mechanical properties, coating properties, and chemical resistance. Compared to their PUUA counterparts, the PUUs with a higher glass transition temperature (T_g), lower crosslinking density and reduced surface N–H proportion showed increase resistance to CEES. Among the PUUs, PUU-PEA prepared from polyether-amine (PEA) exhibited superior chemical resistance and mechanical properties. These findings provide valuable insights for the development of UV-curable chemoprotective coatings.