Effect of unmodified kraft lignin concentration on the emulsion and miniemulsion copolymerization of styrene with n-butyl acrylate and methacrylic acid to produce polymer hybrid latex

The introduction of non-modified kraft LignoBoost (R) lignin (KL) to produce polymer hybrid latex has received much attention in recent years because it is derived from renewable resources. The focus of this work is to develop a polymer hybrid latex by emulsion and miniemulsion copolymerization of styrene with n-butyl acrylate and methacrylic acid in the presence of different concentrations of KL furnished by the pulp and paper industry. The study intends to substitute a styrene in the system to understand the effect of non-modified KL on the properties not only of the latexes, but also on the copolymers themselves. Each polymerization was carried out by shot-process of tertbutyl hydroperoxide and sodium formaldehyde sulfoxylate as the redox system. The polymer latexes were characterized in relation to overall conversion, particle diameter, particle morphology, coagulum formation, surface tension, zeta potential, and atomic force microscopy. The polymers were evaluated through gel permeation chromatography, water absorption, and thermal properties. The results show that the addition of non-modified KL results in inhibition of the polymerization and that KL acts as a colloid stabilizer. Small particles were generated in the initial stages of the polymerizations. The presence of the KL altered the color of the latexes; the increase in KL concentration resulted in increase in the absorption of water of the polymer films; the increase in KL concentration resulted in decrease of the molar mass of the copolymers.