a process for the production of a copolymer from at least one monomer which is gaseous under the polymerization conditions and at least one monomer that is liquid under the polymerization conditions by copolymerizing the same discontinuously in an aqueous media employing a polymerization vessel under conditions whereby a gas space is required , said gas space being provided by a second vessel connected to the polymerization vessel through a closeable connection , whereby on completion of polymerization , the closeable connection is closed in order to retain the gaseous monomer under pressure .