Disulfide‐Functionalized Polyurethanes Serve as UV‐Curable One‐Component Adhesives

Abstract

One‐component polyurethane (PU) adhesives typically cure through the reaction between –NCO functional groups and moisture in ambient air, requiring moisture‐free storage. In this study, we present a novel one‐component polyurethane adhesive that cures via UV irradiation and is resistant to moisture during storage. The polyurethanes were synthesized by polymerizing diisocyanate, polytetramethylene ether glycol, and bis(hydroxymethyl)‐1,2‐dithiolane. The incorporated dithiolane moieties, inherently photo‐responsive, enable efficient cross‐linking under UV light without the need for external photo‐initiators or light absorbers. Rheological analysis of both uncured and cured polyurethanes confirmed their suitability for adhesive applications. The 4,4′‐methylene bis(cyclohexyl isocyanate)‐derived polyurethane exhibited the highest tensile strength, with stress at a break of 3.49 ± 0.24 MPa and an elongation of 74.38% ± 7.47%. This polyurethane served as an adhesive and achieved robust bonding performance on various transparent plastic sheets, with a bonding strength of up to 5.88 ± 0.49 MPa on polyvinyl chloride (PVC) substrate.