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.

The substitution of petroleum-based synthetic polymers in latex formulations with sustainable and/or bio-based sources has increasingly been a focus of both academic and industrial research. Emulsion polymerization already provides a more sustainable way to produce polymers for coatings and adhesives, because it is a water-based process. It can be made even more attractive as a green alternative with the addition of starch, a renewable material that has proven to be extremely useful as a filler, stabilizer, property modifier and macromer. This work provides a critical review of attempts to modify and incorporate various types of starch in emulsion polymerizations. This review focusses on the method of initiation, grafting mechanisms, starch feeding strategies and the characterization methods. It provides a needed guide for those looking to modify starch in an emulsion polymerization to achieve a target grafting performance or to incorporate starch in latex formulations for the replacement of synthetic polymers.

Regenerated starch nanoparticles (RSNPs) produced from dent corn, an amylose‐rich source of starch, are added to an emulsion polymerization. To reduce or eliminate the challenges of polymerizing in the presence of amylose‐rich starch, a seeded, semibatch, monomer‐starved approach is used. To prevent the accumulation of water soluble amylose in the aqueous phase, reaction with a hydrophobic compatibilizing monomer, butyl acrylate, is used prior to the primary butyl acrylate/methyl methacrylate/acrylic acid feed. In addition, an elevated initiator concentration is used in the seed stage to reduce the molecular weight of the soluble starch and promote grafting. The procedure yields a 100.0 cp latex with 40 wt % solids, 25 wt % RSNP loading, and 40 wt % incorporation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46485.

Monomer reactivity ratios are important parameters used in copolymerization kinetics to predict the rate of polymerization, copolymer composition and monomer sequence length, and by extension, molecular weight and distribution of the final product. Batch aqueous solution copolymerizations of acrylic acid (AA) and itaconic acid (IA) are performed at various feed compositions. Polymerizations are categorized into low (<11 wt %) conversion and higher (< 30 wt %) conversion data sets for analysis. Due to the limited solubility of IA in the reaction mixture, the feed composition of IA in all polymerizations is constrained to lower than 25 mol %. Conversion is determined by gravimetric methods, and copolymer composition via 1H‐NMR spectroscopy. All data are analyzed using the error‐in‐variables model (EVM) method. Two analyses are used, one with the EVM approach and another with a novel Direct Numerical Integration (DNI) coupled with the EVM method. The DNI/EVM approach yields values of rAA = 0.36 and rIA = 1.62 for the reactivity ratios. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44014.

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