Cellulose aerogel particles: control of particle and textural properties in jet cutting process
Baldur Schroeter, Velislava P. Yonkova, Noreen A. M. Niemeyer, Isabella Jung, Imke Preibisch, Pavel Gurikov, Ирина Смирнова
Abstract
Abstract Reported approach aims for the synthesis of spherical cellulose beads with high production rates (0.7–4.1 kg/h of hydrogel) via the so-called jet cutting method. To form particles, jets of aqueous cellulose/sodium hydroxide solutions were cut into pieces and collected in a gelation bath (30 wt% aqueous H 2 SO 4 , 20 °C). After solvent exchange with ethanol and subsequent supercritical drying, cellulose aerogel particles were obtained. The particles showed high specific surface areas (ca. 400 m 2 /g) and low bulk (untapped) densities (0.06–0.10 g/cm 3 ). Variation of cellulose content (4–7 wt%) and jet cutting process parameters (cutting frequency, nozzle diameter, jet velocity) turned to be useful parameters for controlling the particles size and shape. Highly spherical particles with sphericity SPH ≥ 0.92 were obtained in a broad range of achievable particle sizes (0.4–1.0 mm), with an optimum of SPH at 6 wt% cellulose content.