| Abstract: | Three different emulsifier types from vinyl acetate monomer and methoxypolyoxyethylene (35: 65, 27: 73 and 19: 81wt: wt%) were prepared in the presence of benzoyl peroxide using a macroradical initiator technique. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance were carried out to confirm the structure of the copolymers obtained (emulsifiers). The emulsion polymerization of vinyl acetate initiated by sodium persulphate as an initiator in the presence of non-ionic (polyoxyethylene (POE) type) emulsifier has been kinetically investigated. The rate of polymerization was found to be proportional to the 0·33, 0·40 and 0·44 power of the emulsifier concentration and to the 0·71, 0·79 and 0·87 power of the initiator concentration. The apparent activation energy was found to be 135, 56·5 and 38kJmol-1 for 65wt%, 73wt% and 81wt% POE, respectively. The particle size was observed to increase with increasing initiator concentration and to decrease with increasing emulsifier concentration. The reaction order with respect to the emulsifier concentration (number of particles versus emulsifier concentration) was found to be 0·10, 2·05 and 0·89 for 65wt%, 73wt% and 81wt% POE, respectively. ©1997 SCI |
