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Despite national and international regulations, plastic microbeads are still widely used in personal care and consumer products (PCCPs) as exfoliants and rheological modifiers, causing significant microplastic pollution following use. As a sustainable alternative, microbeads were produced by extrusion of biomass solutions and precipitation into anti-solvent. Despite using novel blends of biodegradable, non-derivatized biomass including cellulose and Kraft lignin, resulting microbeads are within the shape, size, and stiffness range of commercial plastic microbeads, even without crosslinking. Solution processability and resulting bead shape and Young’s modulus can be tuned via biomass source, concentration, and degree of polymerization; biomass concentration, extrusion geometry, and precipitation and extraction conditions control the bead size. Lignin incorporation reduces the solution viscosity, which improves processability but also produces flatter beads with higher moduli than cellulose-only microbeads. While some lignin leaches from the beads when stored in water, adding surfactants like sodium dodecyl sulfate suppresses this effect, resulting in good mechanical stability over 2 months with no noticeable structural degradation. The stability of these mixed-source biomass microbeads—despite the absence of chemical crosslinking or derivatization—makes this route a promising, robust approach for obtaining environmentally-benign microbeads of tunable size and stiffness for use in PCCPs.
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Continuous synthesis of elastomeric macroporous microbeads
Macroporous microbeads are synthesized by microfluidic production of silica-loaded polymeric microdroplets followed by porogen removal via selective etching. Microdroplets are produced in a flow-focusing microreactor to ensure monodispersity with uniform porogen loading. Effects of porogen size and polymer network density on the porosity and effective modulus of the microbeads are studied.
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- Award ID(s):
- 1803428
- PAR ID:
- 10098951
- Date Published:
- Journal Name:
- Reaction Chemistry & Engineering
- Volume:
- 4
- Issue:
- 2
- ISSN:
- 2058-9883
- Page Range / eLocation ID:
- 254 to 260
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C8RE00189H
