Vinyl polymerization initiated with the lanthanum versatate/p‐chlorobenzenediazonium tetrafluoroborate system

Abstract

AbstractThe system of lanthanum versatate (1) and p‐chlorobenzenediazonium tetrafluoroborate (2) was found to induce effectively polymerizations of electron‐accepting monomers such as methyl methacrylate (3) and di‐2‐ethylhexyl itaconate (DEHI). The polymerization rate (Rp) was expressed by Rp = k[1/2]0,44 [3]0,65 at 50°C fixing the mole ratio of 1 and 2 at unity. The overall activation energy of the polymerization was calculated to be 37, 1 kJ · mol−1. The spin trapping result revealed that the initiator system produces p‐chloropheneyl radicals. The polymerization system of DEHI was observed to involve ESR‐observable propagating polymer radicals, indicating that the polymerization initiated with the 1/2 system proceeds through radical mechanism. During the polymerization, the ESR spectrum was changed in shape, suggesting that the propagating polymer radicals interact with some species formed by the initiation reaction. Interacting polymer radicals were also observed in the polymerizations of diethyl itaconate and N‐dodecylmaleimide with the 1/2 system. The polymerization systems of MMA, styrene and butyl acrylate were also found to involve ESR‐observable radicals, although it is vague whether they are propagating polymer radicals or not.