Melanges de Polyurethannes-Urees et de Polydimethylsiloxanes. Controle de la Morphologie Par UN Copolymere a Blocs (Urea-Polyurethane and Polydimethylsiloxane Mixtures. Morphology Control Using a Block Copolymer)

摘要

The synthesis of polyurethane-urea resins is described. The properties of the resulting elastomer are due to the use of a heavy diamine molecule which diminishes the reactivity of the amine groups and keeps a high cohesion of the formed rigid segments. These elastomers are shown to be usable up to 250 C. A polydimethylsiloxane network was introduced as a demolding agent. As these two polymers are not miscible, an emulsifying agent was incorporated. It is a block copolymer, used in a proportion 0.5 to 2 percent, and it improves considerably the overall properties.