Modification of Adhesive and Latex Properties for Starch Nanoparticle-Based Pressure Sensitive Adhesives

Starch nanoparticle (SNP)-based pressure sensitive adhesives (PSAs) with core-shell particle morphology (starch nanoparticle core/acrylic polymer shell) are produced via seeded, semi-batch emulsion polymerization at 15 wt% SNP loading (relative to total polymer weight) and 40 wt% latex solids. Crosslinker and chain transfer agent (CTA) are introduced to the acrylic shell polymer formulation at a range of concentrations according to a 3(2) factorial design to tailor the latex and adhesive properties of SNP-based latexes. The crosslinker and CTA show no significant effect on polymerization kinetics, particle size, and viscosity. Latex gel content is predicted using an empirical model, which is a function of crosslinker and CTA concentration. Both the gel content and glass transition temperature strongly affect the adhesive properties (tack, peel strength, and shear strength) of the SNP-based latex films. 3D response surfaces for the adhesive properties are constructed to facilitate the design of SNP-based PSAs with desired properties.