Pulsed Electron Beam Polymerization of Styrene in Latex Particles

Abstract

The polymerization of styrene in latex particles by means of pulsed high-energy electrons has been studied. Using a sequence of electron beam pulses, periodic initiation is accomplished, similar to that used in pulsed laser polymerization. The larger penetration depth of electron beams offers advantages as compared to laser light in heterogeneous systems since samples do not need to be optically transparent. Therefore pulsed electron beam irradiations are more suitable to study polymerizations homogeneously irradiated in emulsion. From the molar mass distribution of the formed polymer, the monomer concentration in the particles can be determined. Polystyrene particles swollen with styrene were used. A typical dose per pulse was 1.5 Gy. The monomer concentration in 46 nm diameter particles was found to be 6 mol dm -3 . Cationic and anionic polymerization of styrene was suppressed by the presence of water.