Synthesis and Polymerizations of Six Aminophosphonate-Containing Methacrylates

Two different groups of novel aminophosphonate-containing methacrylates were synthesized. The route to the first group involves reactions of ethyl alpha-bromomethacryate (EBBr) and t-butyl alpha-bromomethacryate (TBBr) with diethyl aminomethylphosphonate and diethyl 2-aminoethylphosphonate. Bulk and solution polymerizations at 60-80 degrees C with 2,2'-azobis(isobutyronitrile) (AIBN) gave crosslinked or soluble polymers depending on monomer structure and polymerization conditions. Increasing bulkiness from ethyl to t-butyl decreases the polymerization rate, correlated well with the chemical shift differences of double bond carbons and consistent with the lower molecular weights of t-butyl ester polymers (M(n) 1800-7900 vs. 50,000-72,000). The route to the second group involves the Michael addition reaction between diethyl aminomethylphosphonate and diethyl 2-aminoethylphosphonate with 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) to give secondary amines. The photopolymerization using differential scanning calorimeter showed that these monomers have similar or higher reactivities than AHM, even though AHM has two double bonds. The high rates of polymerization of these monomers were attributed to both hydrogen bonding interactions due to additional NH groups as well as chain transfer reactions. All the homopolymers obtained produced char (17-35%) on combustion. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 5042-5048, 2011