Development of solvent-free UV-curable polysiloxane–polyurethane acrylate hybrid systems

Traditional solvent-based methods for polyurethane preparation suffer from large VOCs emissions, solvent residue, high energy consumption and poor safety. In contrast, silicone modification can effectively improve the hydrophobicity and chemical resistance of polyurethane. In this study, solvent-free reaction was adopted to synthesize polyurethane, with polytetramethylene ether glycol and isophorone diisocyanate as raw materials, single-terminal monohydroxy polysiloxane, double-terminal monohydroxy polysiloxane and single-terminal dihydroxy polysiloxane as functional monomers, and hydroxyethyl acrylate as the capping monomer. After the addition of a photoinitiator, high-performance hydrophobic polyurethane coatings were fabricated upon 365 nm LED-UV curing. The modified polyurethane exhibits a reduced viscosity (decreased by 20%). The cured coatings possess improved mechanical properties (increased by 20–60%), excellent hydrophobicity (water contact angle of 111.33°), favorable water resistance (water absorption of 1.51%), outstanding abrasion resistance (wear index reduced by 10%) and superior chemical resistance. Owing to the comprehensive and outstanding performances, the prepared polyurethane can be used as a resin to develop hydrophobic coatings through formula adjustment.