BLOCK POLYMER OF POLY (ALKYLSILOXANE) HARD BLOCK POLYMER AND POLYETHYLENE OXIDE POLYMER

摘要

A polymer mixture is formed from at least 95 volume % of a base polymer and less than 5 volume % of a polymer additive including at least first and second different chains in graft or block copolymer form. The first chains are characterized by a low critical surface tension but have a tendency to exude from the mixture while the second ones lower this tendency. This polymer mixture is formed into the exposed blood- contacting surface of a biochemical devlce. A preferred additive is a block copolymer of (a) polydialkyl siloxanes and (b) a polyurethane, with the base polymer being a polyurethane.