Absolute propagation rates in emulsion polymerization. III. Styrene and isoprene

Abstract

Abstract The study of the rate of polymerization per particle in emulsion systems has been extended to include the following monomers and initiator systems: Monomer Initiator System Styrene Persulfate Styrene CHP‐TETA Isoprene DIBHP‐TEPA In all cases, linear rates of polymerization were obtained in the region where the number of particles can be considered as remaining constant (30–60% conversion). Furthermore, the addition of catalyst in this region did not affect the rate of polymerization, so that a rate per particle could be calculated. From the rates per particle, the following absolute propagation rates were calculated for styrene and isoprene, and are compared with values obtained for styrene from photoinitiation studies: Monomer Catalyst system E act. A k p at 60°C. Styrene Persulfate 7.4 4.1 × 10 7 277 Styrene CHP‐TETA 8.4 3.3 × 10 7 221 Styrene Photoinitiation 7.8 2.2 × 10 7 176 Isoprene DIBHP‐TEPA 9.8 1.2 × 10 8 50