Tailoring Crosslinked Polyurethane–Acrylate Hybrid Networks Using a High Isocyanate-polyol ratio (NCO/OH) Ratio for Improved Adhesion and Durability

Polyurethane acrylate hybrid coatings have attracted significant attention for protective applications; however, the influence of high NCO/OH ratios and polyol architecture on their performance remains insufficiently explored. Polyurethane/2-hydroxy-1-methylethyl acrylate (PUA/HMEA) hybrid resins were synthesized via a polyaddition reaction using hexam-ethylene diisocyanate and mixed polyols (GP-2000 and GP-4000) at a relatively high NCO/OH ratio of 2.5. The hybrid network structure was confirmed by FTIR analysis. The effect of HMEA incorporation on rheological, mechanical, adhesion, and chemical resistance properties was systematically investigated. The results revealed a significant enhancement in performance with increasing HMEA content, achieving a tensile strength of up to 205 MPa, adhesion strength of 10.5 MPa, and a contact angle of 153°, indicating improved mechanical integrity and surface hydrophobicity. Furthermore, the hybrid coatings exhibited superior resistance to water, solvents, and corrosive environments. These improvements are attributed to the formation of a highly crosslinked network resulting from the combination of a high NCO/OH ratio and reactive acrylate functionality. The findings demonstrate that tailoring network structure through controlled formulation provides an effective strategy for designing high-performance polyurethane–acrylate coatings for demanding industrial applications.

Acrylic; Coating; Corrosion; Hybrid; Polyurethane

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