Effects of large ring‐substituents on radical polymerization behaviour of 2,6‐diisopropylphenyl methacrylate

Abstract 2,6‐Diisopropylphenyl methacrylate (DIPPMA) noted as a monomer bearing the largest ring substituents among polymerizable o‐substituted phenyl methacrylates was homo‐ and copolymerized. Steric hindrance caused by the substituents significantly reduced the overall rate of polymerization and reactivities in copolymerization. Suppression of termination by the steric effect seems to be of minor importance. The ceiling temperature was determined to be 49°C at a concentration of 1 mol · dm−3 in benzene. The overall rate and the degree of polymerization were confirmed to decrease with increasing temperature under the influence of the ceiling temperature. Triad tacticity of poly(methyl methacrylate) derived from poly(DIPPMA) was determined to be rr = 29%, rm = 53%, and mm = 18% at 40°C, indicating that the steric effect of the large substituents on propagation rendered almost random addition.