Monitoring inverse‐phase emulsion polymerization using electrical impedance spectroscopy

Abstract

Abstract Inverse‐phase emulsion polymerization ( IEP ) is a widely used technique for synthesizing polyacrylamide, a product in demand for water treatment and in food industries. Despite its extensive application, challenges exist in controlling and monitoring IEP due to the relatively high polymerization rate and high viscosity of polyacrylamide. We investigated IEP of acrylamide with an industrial solvent, D80 , as the oil phase, azobisisobutyronitrile as an oil‐soluble initiator, and a mixture of sorbitan monooleate (Span 80) and poly(oxyethylene sorbitan trioleate) (Tween 85) as emulsifier. Our study showed that electrical impedance spectroscopy ( EIS ) is an efficient tool for monitoring the progress and characteristics of IEP in real time. The results revealed that the monomer conversion and polymerization rate correlate well with on‐line capacitance measurements using EIS at an appropriate frequency, while changes in conductance correlate well with changes in particle diameter which was validated using an off‐line dynamic light scattering method. © 2014 Society of Chemical Industry