Emulsion Copolymerization of Butyl Acrylate and Glycidyl Methacrylate: Determination of Monomer Reactivity Ratios

Copolymers of butyl acrylate (BA) and glycidyl methacrylate (GMA) wereprepared by batch emulsion copolymerization at 75°C, using potassiumpersulphate (KPS) as an initiator, sodium dodecylbenzene sulphonate (SDBS)as an emulsifier and sodium bicarbonate as a buffer. Composition of copolymers wasdetermined by elemental analysis and the monomer reactivity ratios were estimated byfive conventional linear methods at low monomer conversions, i.e., methods of Mayo-Lewis (ML), Fineman-Ross (FR), inverted Fineman-Ross (IFR), Ezrielev-Brokhina-Roskin (EBR) and Kelen-Tudos (KT). All methods resulted in higher reactivity ratios forGMA comparing to those of BA (ML: rB = 0.15 and rG = 1.51, FR: rB = 0.22 and rG =1.85, IFR: rB = 0.16 and rG = 1.57, EBR: rB = 0.18 and rG = 1.77, and KT: rB = 0.30and rG = 1.57). The results also showed that, compared to homogeneous polymerizations(bulk and solution), reactivity ratio of GMA is reduced in emulsion polymerizationdue to its relative water-solubility, whereas the reactivity ratio of BA isdistinctly increased. The effect of the reactivity ratios on the monomer conversion wasprimarily studied, as well. The results showed that monomer conversion is increasedwhen using higher GMA feed content due to higher reactivity of GMA.