Maltodextrin as stabilizer for emulsion polymerization: Adsorption and grafting behavior

Emulsion polymerization of the three‐monomer system butyl acrylate–styrene–methacrylic acid was performed in batch using a commercial maltodextrin derived from starch degradation as stabilizer. Stable latexes with narrow particle size distributions were obtained in all examined cases. A method was developed to analyze and quantify the partitioning of the maltodextrin between the continuous phase (supernatant) and the particle phase. Significant differences between the polysaccharides adsorbed onto particles with or without emulsion polymerization reaction were observed. The possible reactions of maltodextrin in presence of a radical initiator were studied in aqueous phase, thus confirming maltodextrin degradation. The formation of copolymers involving the original monomers and the stabilizer according to two different reactive pathways was also confirmed. In terms of adsorbed maltodextrin, two different contributions were observed: maltodextrin physically adsorbed and maltodextrin chemically grafted and/or physically incorporated into the polymer. Commercially available maltodextrin is employed as a stabilizer in an emulsion polymerization process instead of a conventional emulsifier. An in‐depth study allows to fully characterize maltodextrin behavior as a stabilizer: it is evaluated the maltodextrin distribution between supernatant, adsorbed onto polymer surface and grafted/incorporated. It is discovered that the radical activation of the maltodextrin during the polymerization leads to copolymer formation and the consequent grafting of the maltodextrin and its incorporation into polymer latex.