Incorporation of Modified Regenerated Starch Nanoparticles in Emulsion Polymer Latexes

Abstract

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 3 wt% concentration of a polymerizable functionalized sugar‐based monomer (FSM) of medium hydrophobicity are incorporated with the polymer particles. Latexes with 15 wt% RSNP loading (dry RSNP/total solids) and 40 wt% total solids achieved an RSNP incorporation with the latex particles of up to 10 wt% of the total RSNPs added to the emulsion formulation, or 1.5 wt% of total solids. A modified RSNP feed strategy at higher loadings of 40 and 50 wt% results in 10 wt% incorporation of the total RSNPs, or 4 and 5 wt% of total solids, respectively. With RSNPs produced using a higher concentration of FSM (6 wt%), 20 wt% RSNP incorporation with the latex particles (8 wt% of total solids) is achieved at 40 wt% RSNP loading. Strategies are successfully developed to incorporate a certain amount of the RSNPs with the synthetic polymer particles at high overall RSNP loadings.