Polyurethane modified by silicone: Synthesis, microstructure and properties

For synthesizing the textile coating agent with high waterproof and moisture permeable performance, water-borne polyurethanes modified by silicone (WSPU) were prepared by polyaddition reaction using poly(tetramethylene oxide) glycol, polyethylene glycol, and α, ω-aminopropyl polysiloxane as mixing soft segments, dimethylolpropionic acid as hydrophilic chain extender, 1, 4-butanediol as hard segment regulator and isophorone diisocyanate. The chemical composition of WSPU was characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy. The microstructure of WSPU films were investigated by differential scanning calorimetry, transmission electron microscopy and positron annihilation lifetime spectroscopy. Mechanical properties of WSPU films were investigated by static tensile test. Results show that modified polyurethane (WSPU) membranes have significant micro-phase separation structure and large hole free volume that result in the increase of moisture permeability, maximum of which could reach 2130.1 g·(m²·d)^-1. This research has the value of industrial promotion.