KINETICS AND POLYMERIZATION CHARACTERISTICS FOR SOME POLYVINYL ACETATE EMULSIONS PREPARED BY DIFFERENT REDOX PAIR INITIATION SYSTEMS

The emulsion polymerization of vinyl acetate was carried out using dif ferent sodium bisulfite adducts (containing the same weight equivalent of bisulfite anion) as reducing agents with potassium persulfate as a n oxidising agent at low temperature. The polymerization evaluation wa s followed by taking samples at regular intervals. The average volume diameters, the areas and the number of polymer particles per unit volu me of water (Nt) for some prepared emulsion latices were calculated wi th the aid of transmission electron microscopy and image analyzer tech niques. Also, it was found that the rate of emulsion polymerization de creases in the following order: acetone sodium bisulfite (AcSBS) > met hyl propyl ketone sodium bisulfite (MpKSBS) > octyl aldehyde sodium bi sulfite (OASBS) > acetaldehyde sodium bisulfite (ASBS) > benzaldehyde sodium bisulfite (BSBS) > salicylaldehyde sodium bisulfite (SSBS) > cy clohexanone sodium bisulfite (ChSBS), while the particle size of the p repared emulsions increases in the following order: (OASBS) < (SSBS) < (BSBS) < (ChSBS) < (MpSBS) < (AcSBS) < (ASBS). Finally, the D-z, D-v/ D-s, number of particles per cm(3) and D-w/D-n were calculated for pol ymer latices obtained. (C) 1998 Elsevier Science Ltd. All rights reser ved.