Abstract: A method of reducing unreacted monomer in a water-soluble or water swellable polymer comprising the steps, i) applying an ultraviolet initiator to the surface of the polymer and ii) irradiating the polymer with ultraviolet light, wherein the ultraviolet initiator is dissolved or dispersed in a liquid medium and in which the liquid medium comprises an organic compound. The method is useful for reducing in the amount of unreacted acrylamide in polyacrylamide. Also claimed is a liquid initiator composition comprising, i) an ultraviolet initiator, and ii) a liquid medium comprising an organic compound. The initiator system is useful for applying to the surface of a polymer, such as polyacrylamide, in the removal of unreacted monomer, such as acrylamide.

Abstract: A process of preparing water soluble or water swellable polymer comprising the steps, (a) forming an aqueous mixture comprising, (i) a water soluble ethylenically unsaturated monomer or blend of monomers and, (ii) an ultra violet initiator, (b) effecting polymerisation by subjecting the aqueous mixture formed in step (a) to polymerisation conditions to form a polymer of said monomer or monomer blend, (c) subjecting the polymer formed in step (b) to ultra violet light radiation, characterised in that the polymerisation step (b) is conducted substantially in the absence of ultra violet radiation. In one preferred aspect the ultra violet initiator is distributed throughout the polymer formed in step (b). In another preferred aspect the step (c) is conducted ultra violet light at an intensity of up to 500 milli Watts/cm2.

Abstract: A process of preparing water soluble or water swellable polymer comprising the steps, (a) forming an aqueous mixture comprising, (i) a water soluble ethylenically unsaturated monomer or blend of monomers and, (ii) an ultra violet initiator, (b) effecting polymerisation by subjecting the aqueous mixture formed in step (a) to polymerisation conditions to form a polymer of said monomer or monomer blend, (c) subjecting the polymer formed in step (b) to ultra violet light radiation, characterised in that the polymerisation step (b) is conducted substantially in the absence of ultra violet radiation. In one preferred aspect the ultra violet initiator is distributed throughout the polymer formed in step (b). In another preferred aspect the step (c) is conducted ultra violet light at an intensity of up to 500 milli Watts/cm2.

Abstract: Apparatus and method for degassing liquids particularly cationic monomers. Fluid comprising liquid to be degassed together with sweep gas is admitted tangentially into a column (10) and forced down the column by a tubular baffle (16) which defines, with the inner wall of the column, an annulus (18) that is closed at its top (20). After passing to the bottom of the annulus the fluid forms an even film over the inner surface of the column and gas disengaging from the liquid can rise up the column while liquid accumulates at the bottom of the column. To assist the disengagement of the gas from the liquid the column is preferably of increasing cross section towards the bottom so that the thickness of the film is also reduced.