Incorporation of Modified Regenerated Starch Nanoparticles in Emulsion Polymer Latexes

Emulsion polymerization produces a water-borne latex (without the use of solvents), and requires low catalyst concentrations to proceed, making it a more sustainable way to produce polymers than many alternatives. The addition of bio-sourced materials to the formulation further increases sustainability. Vinyl functionalized regenerated starch nanoparticles (RSNPs) are used in semi-batch emulsion polymerizations to prepare starch-incorporated latexes with reduced synthetic polymer content. Nanoparticles with 3wt% concentration of a polymerizable functionalized sugar-based monomer (FSM) of medium hydrophobicity are incorporated with the polymer particles. Latexes with 15wt% RSNP loading (dry RSNP/total solids) and 40wt% total solids achieved an RSNP incorporation with the latex particles of up to 10wt% of the total RSNPs added to the emulsion formulation, or 1.5wt% of total solids. A modified RSNP feed strategy at higher loadings of 40 and 50wt% results in 10wt% incorporation of the total RSNPs, or 4 and 5wt% of total solids, respectively. With RSNPs produced using a higher concentration of FSM (6wt%), 20wt% RSNP incorporation with the latex particles (8wt% of total solids) is achieved at 40wt% RSNP loading. Strategies are successfully developed to incorporate a certain amount of the RSNPs with the synthetic polymer particles at high overall RSNP loadings.