A method for carrying out the continuous polymerization of a monomer in a carbon
dioxide reaction medium comprises the steps of: (a) providing an apparatus including
a continuous reaction vessel and a separator; (b) carrying out a polymerization
reaction in the reaction vessel by combining a monomer and a carbon dioxide reaction
medium therein (and preferably by also combining an initiator therein), wherein
the reaction medium is a liquid or supercritical fluid, and wherein the reaction
produces a solid polymer product in the reaction vessel; then (c) withdrawing a
continuous effluent stream from the reaction vessel during the polymerization reaction,
wherein the effluent stream is maintained as a liquid or supercritical fluid; then
(d) passing the continuous effluent stream through the separator and separating
the solid polymer therefrom while maintaining at least a portion of the effluent
stream as a liquid or supercritical fluid; and then (e) returning at least a portion
of the continuous effluent stream to the reaction vessel while maintaining the
effluent stream as a liquid or supercritical fluid. The need for significant recompression
of the continuous effluent stream prior to return to the reaction vessel is thereby
minimized. Apparatus for carrying out such methods is also disclosed.
