Question

why does methyl methacrylate polymerize faster than styrene?

Answer 1

The rate of polymerization is directly proportional to the square root of initiator concentration. During the initial reaction the polymerization rate of methyl methacrylate monomer is first order with respect to monomer concentration and square root of initiator concentration. Methyl methacrylate also exhibits lowers exothermic heat of polymerization than styrene.

Also in radical polymerization, a methacrylate forms tertiary radicals (which is more stable than a secondary radical which is in the case of styrene). The stability of the tertiary radical is thought to lower the reactivity of the propagating end for further polymerization.