Long-chain alkyl and silicon co-modified waterborne polyurethane coatings: Combining hydrophobicity with synergistically enhanced mechanical properties

Conventional waterborne polyurethanes face limitations in high-performance coating applications for specialized engineering fields due to insufficient mechanical strength and poor water resistance. Herein, we propose a composite modification strategy combining side-chain organosilicon grafting with long aliphatic hydrophobic chain extenders to design and fabricate a series of waterborne polyurethane coatings (GWPU‑X). The effects of glycerol monolaurate (GML) content on emulsion stability and coating properties were systematically investigated. Results indicate that appropriate GML incorporation significantly enhances the coatings’ water resistance, mechanical properties, thermal stability, and adhesion. Specifically, the GWPU‑6 coating prepared with 6 wt% GML exhibits a tensile strength of 40.57 MPa and an elongation at break of 1660.42%. Meanwhile, it achieves a water contact angle of 108.17°, demonstrating excellent hydrophobicity. Furthermore, GML modification effectively improves the thermal stability and adhesion of the coatings, yielding optimal overall performance. This work provides a novel fabrication strategy for developing waterborne polyurethanes that integrate high strength with hydrophobicity, showing considerable potential for practical applications.