Bio-based fluorine-free branched polyurethane@organosilicon water-repellent agent for cotton fabric

In recent years, with the increasing consciousness on environment protection, fluorine-free water-repellent agents in textile industry have attracted considerable attention. Herein, we proposed a new strategy to prepare bio-based fluorine-free branched polyurethane@organosilicon water-repellent agent for cotton fabric (CF). Branched polyurethane (BPU) with long alkyl chains was firstly synthesized through the reaction of glycerin monostearate extracted from natural palm fruit, toluene diisocyanate, trimethylopropane and N-methyl diethanolamine, and then utilized to coat the C24-28 olefin modified hydroxyl silicone oil (C24-28 HSO) by emulsification procedure to obtain branched polyurethane@organosilicon (BPU@C24-28 HSO) water-repellent agent. Fourier transform infrared spectroscopy and H-1 nuclear magnetic resonance spectroscopy confirmed the chemical structures of BPU, C24-28 HSO and BPU@C24-28 HSO water-repellent agent. The biomass carbon content of the water-repellent agent reached 54.0%. Transmission electron microscope demonstrated that the BPU@C24-28 HSO water-repellent agent appeared obvious spherical shape with core-shell structure. Owing to the introduction of organosilicon, the water-repellent agent significantly improved the softness of the CF. In addition, the CF finished by the BPU@C24-28 HSO water-repellent agent also exhibited excellent water-repellent score of 90+, high water contact angle of 141.6 degrees and superior surface stability. Our findings provided a direction to prepare environmental-friendly and high-performance water-repellent agents for various fabrics.