Preparation of homogeneous polymers using supercritical fluid solutions

摘要

Homogeneous polymer blends are prepared from otherwise thermodynamically immiscible polymers, especially including block copolymers. Thus, polymers such as polystyrene/poly(methyl methacrylate) block copolymer or polystyrene/poly(1,2-butadiene) block copolymer are dissolved under pressure in supercritical fluid solvents such as chlorodifluoromethane and n-butane, respectively, and expanded through a fine nozzle. As the SCF solvent evaporates, the polymer deposits as a substantially homogeneous material.