Microbeads are solid, approximately spherical particles with diameters between one micrometre and one millimetre, distinguished from irregular powders by sphericity and a narrow size distribution rather than by composition [1]. Glass grades are drawn and milled, while polymer microbeads are produced by emulsion, suspension or dispersion polymerisation, in which monomer droplets or swollen particles set into spheres [2]. Diameter, density and surface chemistry are the defining descriptors, since buoyancy in water and retention on a filter both follow from them [3]. Particles of this size range are classed with microplastics when the polymer resists degradation, and that persistence separates them from mineral or glass beads of equal diameter [3]. Encapsulation of a colloidal core within a polymeric bead adds an internal phase without changing the outer geometry [2].
- plastic microbead
- suspension polymerisation
- sphericity
- microplastic
- particle size distribution
References
- Perren, W.; Wojtasik, A.; Cai, Q.; Removal of Microbeads from Wastewater Using Electrocoagulation. ACS Omega 2018, 3, 3357-3364, 10.1021/acsomega.7b02037.
- Yang, Y.; Tu, C.; Gao, M.; A general approach for encapsulating aqueous colloidal particles into polymeric microbeads. Journal of Materials Chemistry 2007, 17, 2930, 10.1039/b703060f.
- Budov, V.V.; Egorova, L.S.; Glass microbeads, application, properties, and technology (Review). Glass and Ceramics 1993, 50, 275-279, 10.1007/bf00683661.