Role of grafting on particle morphology and film properties of polyurethane-polyacrylate hybrid dispersions.

Abstract

Typically, the PU/acrylic hybrid nanoparticle dispersions are prepared in multistep procedure, composed of synthesis of PU in organic solvents, dispersion of PU/solvents into water, solvent removal, addition of acrylic monomers into the dispersion and their free radical polymerization. Besides being complex and expensive, this method has negative implications for sustainability of the synthesis.In this work, solvent and emulsifier-free PU/acrylic hybrid dispersions were synthesized using (meth)acrylic monomers as solvent in the PU synthesis and grafted hybrids were prepared with different functional monomers. The effect of grafting and the impact of macromolecular architecture on the particle and film morphology and physical properties of PU/(meth)acrylic hybrid films is investigated. It was found that grafting improved the compatibility of PU and (meth)acrylics and resulted in films with better mechanical properties and water sensitivity. The grafting of PU and acrylic chains can result in a huge variety of macromolecular structures, depending on the nature of both the PU and the acrylic parts of the formulation.