Preparation and properties of waterborne polyurethane modified by stearyl acrylate for water repellents

Double bond end-capped waterborne polyurethane (DWPU) was synthesized from toluene diisocyanate, hydroxypropyl polysiloxane, trimethylolpropane, N-methyldiethanolamine, and hydroxyethyl acrylate. Then water repellents with long-chain hydrophobic alkyl structure were obtained by radical copolymerization of stearyl acrylate (SA) and DWPU. The waterproofing performance and other properties of the water repellents were studied for different SA contents. The results showed that, for the water repellent with SA content of 50 wt%, the water absorption of the film reduced to 4.29% while the water contact angle of fabric coated by the water repellent rose to 141.5°. In addition, the optimum SA content of the water repellent was 40%, achieving the highest score of 85 points in the waterproof performance evaluation.