Analysis of semibatch emulsion polymerization: Role of ultrasound and initiator

In this work semibatch miniemulsion was carried out wherein the effect of free radicals produced by ultrasound and an external addition of initiator was examined. Influence of different variables on polymerization rate and polymer particle size has also been investigated. Over a range of 0–4% (by wt) initiator, the polymerization rate was found to increase over a range of 0.56–1.33 g L−1 min−1. Similarly monomer concentration range (7.2–15 wt.%) changed the polymerization rate from 1.33 to 2.61 g L−1 min−1. Under optimum parametric conditions polymer particle size 50 nm were obtained with a narrow size distribution. Syndiotactic phase of PMMA was observed by controlling the formulation recipe. Although, number of reports could be found in the literature [9], [13], [17], [18], [20] and [22] related to batch emulsion polymerization, this experimental data could be useful for the production of large scale monodispersed PMMA latex as all of the scale-up and design parameters have been qualitatively addressed.

► Scale-up and design parameters for production of large scale monodispersed PMMA latex particles.
► Syndiotactic phase of synthesised PMMA particles.
► Particles with narrow size distribution and mean size of 50 nm were effectively synthesized.
► Cavitational effects induced by ultrasound supplement the role of the initiator.