Cellulose Aerogel Microparticles via Emulsion-Coagulation Technique

Abstract

Cellulose aerogel microparticles were made via emulsification/ nonsolvent induced phase separation/drying with supercritical CO 2 . Cellulose was dissolved in NaOH-based solvent with and without additives in order to control solution gelation. Two emulsions, cellulose solution/oil and cellulose nonsolvent/oil, were mixed to start nonsolvent induced phase separation (or coagulation) of cellulose inside each cellulose droplet leading to the formation of so-called microgels. Different options of triggering coagulation were tested, by coalescence of droplets of cellulose solution and cellulose nonsolvent and by diffusion of nonsolvent partly soluble in the oil, accompanied by coalescence. The second option was found to be the most efficient for stabilization of the shape of coagulated cellulose microgels. The influence of gelation on particle formation and aerogel properties was investigated. The aerogel particles' diameter was around a few tens of microns, and the specific surface area was 250−350 m 2 /g.

Synthesis of nanocellulose aerogels and Cu-BTC/nanocellulose aerogel composites for adsorption of organic dyes and heavy metal ions

“…Cellulose is a promising polymer for the preparation of aerogel compounds due to its unique properties such as inexpensive 48 , renewable 49 , degradable 50 , abundant 51 , non-toxic 52 , and environmentally friendly 53 . In particular, nanocellulose materials show a specific promise for use in aerogel materials, since by reducing the size of cellulose fibers, completely uniform materials with advanced mechanical properties can be obtained 15 , 19 .…”

Spherical Cellulose Micro and Nanoparticles: A Review of Recent Developments and Applications

“…As an illustrative example, Kim et al [ 92 ] developed cellulose hydrogel beads with a diameter of ca. 2.0 mm for the immobilization of lipase from Candida rugosa , as shown in Figure 1 E. In more recent studies, Druel et al [ 93 ] produced cellulose aerogel microparticles with diameters in the range of 5.4 ± 1.8 μm to 20.9 ± 8.9 μm via emulsion-coagulation technique ( Figure 1 F), while Chin et al [ 94 ] fabricated cellulose nanoparticles with diameters ranging between 70 and 365 nm by the nanoprecipitation method ( Figure 1 G).…”

Recent Progress in High‐Strength and Robust Regenerated Cellulose Materials

“…Spherical materials show great potential in various fields such as nanomedicine, separation technology, and biocatalyst immobilization and carriers. [ 111–115 ] Zhang and co‐workers fabricated microspheres from cellulose solution in NaOH/urea solvent by the sol–gel transition method. The mean diameter (5–1500 µm) of the cellulose microspheres could be controlled by adjusting the experimental parameters such as the amount of the surfactants, the proportion of the water to the oil phase, and the stirring speed.…”