Chain transfer to solvent in the radical polymerization of structurally diverse acrylamide monomers using straight-chain and branched alcohols as solvents

Abstract

Chain transfer to solvent in conventional radical polymerizations of N-tert-butylacrylamide (TBAM) and N-(2-morpholin-4-ylethyl) acrylamide (MEA) in a range of alcohol solvents is investigated. Mayo analysis of polymerization of TBAM in linear alcohols (C-3-C-9) resulted in an approximately linear increase in chain transfer to solvent constant (C-tr,(S)) with the number of methylene (CH2) units in the solvent. The branched alcohol 3-methyl-3-pentanol gave the smallest C-tr,C-S (using Mayo analysis), and thus allowed attainment of higher molecular weights (MWs) in the nitroxide-mediated polymerizations (NMP) of TBAM. Overall, the data show that MEA is more prone to chain transfer to solvent than TBAM (higher C-tr,C-S), and further analysis of the conventional radical polymerization of MEA in 3-methyl-3-pentanol indicate chain transfer to monomer may also be occurring. The first controlled/ living polymerizations of MEA are detailed with chain transfer having a greater impact on maximum achievable MWs in NMP in comparison to TBAM.