Preparation and Performance Evaluation of Waterborne Polyurethane Modified with Silane Coupling Agent and Castor Oil

Abstract

An environmentally friendly waterborne polyurethane (CWPU) emulsion was developed via a dual modification strategy by combining both the silane coupling agent KH-602 with renewable castor oil (CO) as a sustainable substitute for petroleum-based polyols. The resulting materials were thoroughly characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Furthermore, the influence of KH-602 content on the material properties was systematically investigated. The experimental results reveal that the incorporation of KH-602 significantly improves the thermal stability of the composite coating. As the KH-602 content increases, the tensile strength exhibits a gradual enhancement, while the elongation at break displays an initial increase followed by a subsequent decline. At an optimal KH-602 content of 3%, the coating demonstrates a balanced performance, achieving a tensile strength of 14.19 MPa and an elongation at break of 731.12%. These results suggest that the dual modification approach enhances mechanical and thermal properties while maintaining water resistance, making it suitable for sustainable coating applications.

Keywords

silane coupling agent / waterborne polyurethane / modification

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