Coating of Polyester with Poly(dimethylsiloxane)- and Poly(tetramethylene oxide)-based Polyurethane

Copolymers siloxane–urethane are prepared to coat polyester fabrics to make them hydrophobic. Initially, our focus was on the bulk synthesis of poly(siloxane–urethane) in two steps: the first relates to the formation of a prepolymer between the isophorone diisocyanate and a poly(oxytetramethylene) glycol. In the second step, 1,4-butanediol is added, as the chain extender. Thus two types of polyurethanes are obtained according to whether poly(dimethylsiloxane) is introduced in the first or in the second step. Then the polyester fabric is impregnated with the prepared formulations. The contribution of coating during the mechanical tests is checked. The measurement of contact angles makes it possible to control the waterproofing effect expected for this kind of formulation.