Semi‐Continuous Emulsion Copolymerization of Styrene‐Butyl Acrylate with Methacrylic Acid: Box‐Behnken Design of Experiments

Abstract

A three-factor three-level Box-Behnken design was conducted to study the semicontinuous emulsion copolymerization of styrene (St)/butyl acrylate (BA) with methacrylic acid (MAA). The effects of St/BA ratio, MAA content, and pH on the carboxylic acid distribution in the latex, the polymer glass transition temperature (T g ), the average latex particle diameter, the molecular weight and distribution of the polymer products, and the coating adhesion to a polycarbonate substrate were investigated. The experimental results showed how the pH affected the distribution of MAA in the polymer particles. Regression analysis revealed how the St/BA ratio, MAA content, and pH influence the copolymer T g , the latex particle size, the number-average molecular weight M n as well as the weight-average molecular weight M w . An empirical model to correlate the pull-off adhesion of the latex coating to a polycarbonate substrate was developed.