Evaluation of propagation rate constants for the free radical polymerization of methacrylonitrile by pulsed laser photolysis

Propagation rate constants for the free radical polymerization of methacrylonitrile (MAN) have been obtained by pulsed laser photolysis (PLP). The temperature dependence of the propagation rate constants indicates a frequency factor of 10^{(6,43 ± 0,26)} L · mol⁻¹ · s⁻¹ and an activation energy of 29,7 ± 1,5 kJ · mol⁻¹. These parameters suggest that the relatively slow rate of propagation in MAN polymerization in relation to other common monomers (methyl methacrylate, styrene) can be attributed to the relative steric bulk and stability of the propagation species.