Optimization of process variables for the micro emulsion polimerization of styrene-butyl acrylate-acrylic acid latexes and determination of divinylbenzene effect on their physicaochemical properties

In this study, firstly the effect of process variables for the preparation of styrene (Sty)/butyl acrylate (BA)/acrylic acid (AAc) copolymer (SAC) latex particles via the semi batch seeded emulsion polymerization was investigated. In this context, the effect of process variables such as monomer ratios, seed amount and surfactant amount on the physicochemical properties of SAC latexes were explained by means of DSC, TG/DTG, SEM, 1H-NMR, FTIR, MFFT, and DLS techniques. Optimization studies showed that the most ideal latex that provides the properties expected from acrylic latexes for practical coating applications is obtained with a monomer ratio of 44: 54: 2 for Sty: BA: AAc. In the second part, divinylbenzene (DVB) crosslinked SAC latexes were prepared by applying the determined optimum conditions and the effect of DVB amount on the stability, film formation and particle size of the latexes were examined. The presence of DVB moity in the SAC latex particles caused increased thermal stability The glass transition characteristics of SAC latex was affected by the addition of DVB. When the DVB ratio was increased from 0% to 2%, the Tg value of the films increased from 7.5 ºC to 24.5 ºC. Minimum film formation temperature (MFFT) values are between 0-9 ºC. The prepared cross-linked latexes were found to have MFFT and Tg values suitable for practical applications. Thus, it was possible to obtain new types of latex with higher mechanical and chemical resistance without increasing the voltalite organic compound (VOC) value.When DVB ratio was increased from 0.5% to 2%, the average particle size changed between 83.62-194.60 nm, and polydispersty index (PDI) values increased from 0.015 to 0.140, respectively. PDI values sufficient for practical applications proved that the applied method can be used in the preparation of cross-linked latexes. PDI values indicate sufficient stability and good dispersibility, have proved that the applied method can be used in the preparation of cross-linked latexes for practical applications. Keywords: Styrene Acrylic Copolymer, Latex, Divinylbenzene, Emulsion Polymerization, Water-Born Paint.