AMINE ACTIVATORS FOR THE COOL PEROXIDE INITIATED POLYMERIZATION OF ACRYLIC-MONOMERS

Two tertiary amines with a chemical structure rather similar to dimeth yl-4-toluidine have been prepared and tested as activators for the fre e radical polymerization of methyl methacrylate. 4-Dimethylaminobenzyl alcohol, DMOH, was synthesized by reduction of the corresponding benz aldehyde. 4-Dimethylaminobenzy1 methacrylate, DMMO, was synthesized by condensation of methacryloyl chloride with DMOH in the presence of tr iethylamine as catalyst. Kinetic studies of the bulk polymerization of methyl methacrylate initiated by the redox system BPO-amine have been carried out by differential scanning calorimetry at different tempera tures in the interval 30-40 degrees C. An increase of the overall rate constant, k, with increasing temperature was observed for all redox s ystems. The system BPO/DMT gave the highest values of h. The polymeriz ations catalyzed by DMOH and DMMO respectively gave lower values of th e overall Arrhenius activation than that obtained with DMT. DMMO may p articipate in the polymerization not only as activator but also as an acrylic derivative which can be incorporated into the polymeric growin g chains during the propagation stp of the free radical polymerization . (C) 1996 John Wiley & Sons, Inc.