One-step synthesis of epoxy-based silicon prepolymers and its application in UV-curable coating

Abstract

As described herein, a simple one-step hydrosilylation reaction was employed to synthesize alicyclic epoxy silicone prepolymers by using poly(dimethylsiloxane-co-methylhydrosiloxane) (PDMS-PHMS) with different hydrogen contents and 4-vinyl-1-cyclohexene-1,2 epoxide (VCHO) as precursors. The structures of the synthesized epoxy polysiloxane oligomer was characterized by Fourier-transform infrared (FTIR) and proton nuclear magnetic resonance (¹H-NMR) spectroscopy techniques, thus confirming the successful synthesis of the prepolymers. With the addition of an appropriate amount of cationic photoinitiator, the epoxy polysiloxane prepolymers undergo cationic polymerization under ultraviolet light irradiation and were quickly cured to yield series of epoxy polysiloxane resin films. The performances of these cured films were tested and characterized by various techniques such as UV transmittance, thermal weight loss analysis, and contact angle and pencil hardness measurements. The results revealed that the surfaces of these films were uniform and transparent, and these films had excellent heat resistance, acid resistance, hydrophobicity, and ink removal properties. In addition, the influence of the cycloaliphatic epoxy monomer content on the curing behavior and network performance is explored. This study reveals that the curing rate increases as the amount of grafted cycloaliphatic epoxy monomer is increased and that a denser crosslinking network provides the resultant film. Finally, the photocurable silicone material investigated herein is simple to prepare and has excellent performance, and has potential applications in the field of anti-smudge coatings.