Rate constants for elementary reactions of the radical polymerization of methyl 2‐(benzyloxymethyl)acrylate as polymerizable acrylate bearing large substitutents

Methyl 2‐(benzyloxymethyl)acrylate (MBZMA) which was synthesized by reaction of methyl 2‐(bromomethyl)acrylate with benzyl alcohol was radically homo‐ and copolymerized. MBZMA polymerized as fast as methyl methacrylate despite of the presence of a large 2‐substituent. The absolute rate constants for propagation and termination were evaluated from the direct determination of the steady state concentration of the propagating radical by electron spin resonance spectroscopy at 60°C: kp = 182 dm3 · mol−1 · s−1 and kt = 1,6 · 106 dm3 · mol−1 · s−1. It was deduced from the magnitude of the rate constants that the balance of the slow propagation and termination allows the formation of a polymer. Evaluation of the cross‐propagation rate constants in the copolymerization with styrene revealed that primarily the steric effect of the benzyloxymethyl group reduced the reactivity of the polymer radical and that the electronwithdrawing character of the 2‐substituent prevailing the steric effect enhanced the monomer reactivity toward the polystyrene radical.