Synthesis and characterization of side aminopolysiloxane modified polyurethane textile coatings

The water-borne side aminopolysiloxane modified polyurethanes (WSSPU) were prepared by polyaddition reaction using poly(tetramethylene oxide)glycol, polyethylene glycol, and side aminopolysiloxane as soft segments, dimethylolpropionic acid as hydrophilic chain extender, 1,4-butanediol as hard segment regulator and isophorone diisocyanate. The waterproof and moisture permeable textile coating agent was then fabricated based on WSSPU. The chemical composition and microstructure of WSSPU were characterized by infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analyzer and positron annihilation lifetime spectroscopy, respectively. The mechanical properties of WSSPU films, the waterproofness and breathability of the coated fabric were determined. The results showed that the stable emulsion can be obtained at the amount of SAPDMS (mass ratio) below 15%. The modified polyurethane membranes had more serious micro-phase separation structure and increased free hole volume, resulting in improved moisture permeability.