Microwave-Assisted Reversible Addition-Fragmentation Chain Transfer Polymerization of Cationic Monomers in Mixed Aqueous Solvents

Cationic polymers are an interesting class of macromolecules due to their versatility and emerging properties that can be used for various industrial and biomedical purposes. This report is focused on investigating the use of microwave heating in the reversible addition-fragmentation chain transfer polymerization of functional cationic monomers, N-(3-aminopropyl)methacrylamide hydrochloride (APMA) and N-[3-(dimethylamino)propyl]methacrylamide (DMAPMA). Under comparable polymerization reaction conditions, the microwave-assisted reaction achieves up to 270% (APMA) and 375% (DMAPMA) rate enhancement over conventional oil-bath mediated set-up. Linear relationships are observed between number average molecular weight and monomer conversion for different target degrees of polymerization to give low- to high-molecular-weight cationic polymers. Chain extension experiments show increase in molecular weight of the cationic polymers with narrow dispersities (<SIC> < 1.2) indicating retention of the chain transfer agent with no observable aminolysis or hydrolysis during polymerization.