ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Partitioned Polymerization. 7. Seeded Emulsion Polymerization of Methyl Methacrylate in the Presence and/or Absence of Fremy's Salt

J. Bartoň and V. Juraničová

Polymer Institute, Slovak Academy of Sciences, SK-842 36 Bratislava

Abstract: The course of seeded emulsion polymerization of methyl methacrylate (MMA) initiated by water-soluble initiator ammonium peroxodisulfate (APS) in the presence of poly(butyl acrylate) seed particles (PBA) depends on the MMA-PBA mass ratio (w_r) and the presence or absence of potassium nitrosodisulfonate (Fremy's salt, FS) in the system. In the presence of FS an inhibition period for both ''low'' (0.637 and 0.675) and ''high'' (3.25) w_r(MMA-PBA) was observed. Retardation of polymerization rate after inhibition period only for ''high'' w_r(MMA-PBA) was found. In conditions of Stage 2 (w_r = 3.250) of seeded emulsion polymerization the rate of seeded emulsion polymerization of MMA initiated by APS is lower than the rate found for Stage 3 (w_r = 0.675). Polymer particle size for a given conversion of monomer depends on the value of w_r(MMA-PBA). Under conditions of Stage 2 of seeded emulsion polymerization the presence of FS lowers slightly the polymer particle size.The results confirmed that the water-phase events of free radicals are of primary importance for core/shell polymer particle formation and generation of a new crop of structurally homogeneous poly(methyl methacrylate) particles.

Full paper in Portable Document Format: 485a351.pdf

Chemical Papers 48 (5) 351–355 (1994)