Waterborne hybrid polymer particles: Tuning of the adhesive performance by controlling the hybrid microstructure

Hybrid polyurethane/acrylic waterborne pressure sensitive adhesives were synthesized by miniemulsion polymerization. The free radical polymerization of a mixture of acrylic and methacrylic monomers, containing 2-hydroxyethyl methacrylate, was carried out in the presence of a diisocyanate terminated polyurethane prepolymer and a diol. The resulting polymer microstructure was varied by altering the PU content and the number of links between the PU and the acrylic chains. The structure of the hybrid polymer was characterized by a combination of macroscopic measurements (gel fraction, swelling ratio, and sol molecular weight distribution) and computer simulations. A detailed study of the relationship between structure and adhesive properties was carried out.