Synthesis and surface properties of dihydroxybutyl terminated-polydimethylsiloxane modified polyurethane

A series of siloxane-modified polyurethanes (Si-PU) were synthesized based on 2,4-tolylene diisocyanate (TDI), dihydroxybutyl-terminated polydimethylsiloxane (DHPDMS), poly(tetramethylene ether) glycol (PTMG) and 1,4-butanediol (BDO). Fourier transform infrared spectroscopy (FT-IR) analysis shows that DHPDMS has been incorporated into the polyurethane chains. With the increase of the content of DHPDMS, the water contact angle increases while the surface tensile force decreases. When the content of DHPDMS is over 5%, both the water contact angle and the surface tensile force tend to a constant. With the increase of temperature, the contact angle increases, and also tends to a constant when temperature is higher than 50°C. The results indicate that Si-PU reaches good surface and mechanical properties when the content of DHPDMS is about 5%.