New unsaturated surfactants for the dispersion polymerisation of methyl methacrylate in supercritical carbon dioxide

This paper describes the synthesis of a siloxane based stabiliser by ring opening metathesis polymerisation of (bicyclo[2.2.1]hept-5-en-2-yl)triethoxysilane using Ru(PCy3)Cl2(CHPh) as the initiator. The resulting polymer was then used as a stabiliser for the free radical polymerisation of methyl methacrylate in supercritical carbon dioxide (scCO2). The poly(methyl methacrylate) (PMMA) formed using poly((bicyclo[2.2.1]hept-5-en-2-yl)triethoxysilane) has high molecular weight and a narrow polydispersity. Under optimised conditions of dispersion polymerisation in scCO2, discrete spherical particles of PMMA are formed with an average diameter of 2.7 μm.