Synthesis and polymerization of new pyrrolidone-containing methacrylate monomers

Seven new pyrrolidone-containing methacrylate monomers have been synthesised and characterised via n.m.r. and FTi.r. These monomers were polymerized using azobisisobutyronitrile as a thermal initiator at 60°C. Basic solubility tests were performed at room temperature and two of the polymers were found to be water soluble, namely poly(2-pyrrolidone-1-isopropenyl ketone) (PPIK) and poly(2-ethyl-2-pyrrolidone methacrylate) (PEPMA). The lower critical solution (LCST) behaviour of these two polymers was investigated and found to be in a temperature range similar to that reported for poly(N-isopropylacrylamide) (PNIPAAM) with onset LCST values (on heating) between 29 and 34°C. The effect was found to be reversible on cooling the solution. A comparison was made with PNIPAAM which seemed to indicate a slightly broader LCST transition for the two new polymers, however no conclusions could be firmly established on this as the molecular weights of the polymers were not measured.