Statistical Analyses of Inverse Miniemulsion Acrylic Acid Polymerizations for Encapsulation of Hydrophilic Compounds

Abstract

Polymer hydrogel nanoparticles are produced through inverse miniemulsion polymerizations, using acrylic acid as monomer and soybean oil as the continuous phase. A crosslinking agent is used to promote the reticulation of the polymer chains and production of hydrophilic nanogels. The synthesis of the polymer nanoparticles is studied with aid of a full factorial design using monomer content, crosslinker content, and reaction temperature as independent variables and monomer conversion and thermal stability of the obtained material as the main responses. The potential to encapsulate hydrophilic actives into the hydrogel matrix is evaluated by using a commercial blue dye as a model. It is observed that incorporation of the blue dye is efficient and that the rates of dye release are very low at different pH values, suggesting the existence of strong physicochemical interactions with the polymer matrix, which can be advantageous in bioimaging and paint applications. Particularly, the proposed inverse miniemulsion procedure enabled the production of stable nanogels.