Emulsion polymerization of styrene with amphiphilic random copolymer as surfactant: Predominant droplet nucleation

Abstract

Amphiphilic random copolymer consisting of monomeric units of poly (butyl acrylate) and poly (maleic acid salt) was synthesized and characterized. The emulsion polymerization kinetics of styrene stabilized by this copolymer was investigated. The influencing factors, including polymeric surfactant concentration, initiator concentration and polymerization temperature, were systematically studied. The kinetic data show that the polymerization rate (R P ) increased with the increase of the polymeric surfactant concentration ([S]) and polymerization temperature (T). At the higher [S], droplets nucleation and micelle nucleation coexisted in the polymerization system; at the lower [S], only the droplets nucleation process existed. The polymerization did not follow Smith-Ewart Case II kinetics. Dynamic light scatter and transmission electron microscope were utilized to measure the sizes and shapes of the particles, respectively. It would be speculated that a kind of large heterogeneous particles with multiple-active-sites was formed in the polymerization system. The increasing of R P with increasing initiator concentration ([KPS]) was rapid at a medium [KPS], but the slowly increasing was observed at a lower or higher [KPS]. It was attributed to the barrier effect of the polymeric surfactant around the monomer droplets. The polymerization activation energy was 60.29 kJ/mol.

Semibatch emulsion copolymerization of butyl acrylate and glycidyl methacrylate: Effect of operating variables

“…In the previous literatures, the effects of different variables on emulsion polymerization have been studied. They covers variables such as agitation speed,1, 6–19 initiator type and concentration,1, 2, 6–8, 15, 16, 18, 20–32 emulsifier type and concentration,8, 18, 20, 21, 24, 25, 28–30, 32–37 feeding rate,3, 11, 26, 30 temperature,1, 6, 7, 16, 21–24, 26, 29, 30, 33, monomer/water phase ratio,8, 15, 18, 20, 29 electrolyte concentration,14, 31 and pH 16, 29…”

“…Majority of the laboratory works have focused on the batch systems,2, 8–10, 12, 14–23, 25, 29–34 and fewer works have been conducted via semibatch1, 3, 6–8, 11, 12, 26, 27, 30, 35, 36, 38 and continuous systems 24, 28, 39…”