Emulsion polymerisation of MMA employing a chain transfer agent of low environmental impact: ISO-octyl-3-mercaptopropionate

The unseeded batch‐emulsion polymerisation of methyl methacrylate (MMA) was investigated using the chain transfer agent iso‐octyl‐3‐mercaptopropionate (iOMP), which exhibits a low environmental impact. The commercial iOMP is a mixture of over 10 isomers that proved adequate to control the molecular weights of poly(methyl methacrylate) with a decreasing evolution of both the number‐ and weight‐average molecular weights along the reactions. The iOMP also affects the polymerisation kinetics as a consequence of the lower reactivity of the iOMP radicals with respect to the MMA‐ended radicals. Experimental results were interpreted with the help of a first principles mathematical model. © 2013 Canadian Society for Chemical Engineering