Gerald Rott

Plastic microbeads serve as exfoliants and rheological modifiers in numerous personal care consumer products, such as soaps, hand sanitizers, and shampoos. While microbeads are important for the function of these products, billions of these beads enter the environment daily. Replacing plastic microbeads with biomass substitutes can negate the toxic effects on marine life that current beads impose. Multiple drip synthesis methods have been successful in tuning morphological and mechanical properties of cellulose microbeads; however, these processes are not scalable. Synthesis of biomass beads through an emulsion allows for the bulk synthesis of these beads. Prior studies in this area achieved proof-of-concept for an emulsion synthesis, but recreating these methods has proven challenging due to trace impurities in the ionic liquid, type and brand of oil, degree of cellulose polymerization, as well as vague reactor size and geometry. A 4 wt% microcrystalline cellulose, 1-ethyl-3-methyl imidazolium acetate ionic liquid solution stirred in an ethanol anti-solvent has showed promising signs. Surfactant concentration, stirring speeds, reactor geometry, temperature, cellulose dissolution procedures, as well as extraction methodology are all critical variables to the success of an emulsion synthesis. By systematically varying stirring speed, surfactant concentration, and oil to cellulose solution, biomass solutions have been partially converted to small, irregular particles reminiscent of beads. By further tuning the mixing parameters of present emulsions, near-total conversion of biomass to usable microbeads is expected soon.