Emulsion copolymerization of methyl methacrylate and ethyl acrylate, 2. Effect of emulsifier concentration and emulsifier blend composition on the polymerization behaviour

Abstract

AbstractThe free radical emulsion copolymerization of methyl methacrylate and ethyl acrylate initiated by ammonium persulfate at 60°C in the presence of a blend of anionic and non‐ionic emulsifiers was investigated. In the interval 2 the rate of copolymerization is approximately proportional to the 0,6th power of the total emulsifier concentration. The number of final polymer particles is proportional to the 0,5th power of the total emulsifier concentration. The dependence of the rate of copolymerization on the composition of the emulsifier system is described by a curve with a maximum at a mole fraction of non‐ionic emulsifier of about 0,5. The mean particle size keeps a constant value until the maximum of the polymerization rate is reached. Beyond this maximum the particle size abruptly increases (mole fraction of non‐ionic emulsifier ≈0,5). The rate of copolymerization, the conductivity and stability of the polymer latex increase, whereas the particle size and interfacial tension of latex and the number‐average molecular weight of copolymer decrease with increasing total concentration of the emulsifier blend.