Monomer effects on emulsion polymerization with ASR as the surfactant

Abstract

In this paper, alkali soluble resin (ASR) was evaluated as a surfactant in the emulsion polymerizations of methyl methacrylate (MMA), ethyl methacrylate (EMA), and butyl methacrylate (BMA). It was found that the number of particles formed was proportional to the hydrophilicity of monomer and the concentration of initiator. Kinetic analysis indicated that the monomer concentration within the latex particle influences the average number of radicals per latex particle. The increase of monomer concentration within the particle enhances radical desorption from the particle and reduces the average number of radicals per particle. Experimental results show that the grafting reaction of ASR is proportional to the concentration of initiator or ASR. But the hydrophilicity of monomer is the major factor which influences the grafting reaction. This phenomenon is due to the fact that particle nucleation is different between the hydrophilic and hydrophobic monomer.