Properties of Cellulose Nanofibers Extracted from Eucalyptus and their Emulsifying Role in the Oil-in-Water Pickering Emulsions

Abstract

In this work, nanocellulose particles were obtained from eucalyptus bers by high-pressure homogenization (CNF) and by high-intensity ultrasound (SCNF). The nanocellulose was applied as a solid emulsi er for soybean oil in water (O/W) emulsions. The adding of 0.25 -1 wt.% of both CNF and SCNF produced stable O/W emulsions without conventional surfactants. SCNF emulsions showed the highest stability and displayed the narrowest size distribution. Zeta potential values (-40 to -70 mV) indicated an electrical barrier to the droplet coalescence. The rheological behavior of O/W emulsions stabilized with CNF and SCNF was described by the Herschel-Buckley model. O/W emulsions produced with nanocellulose particles behave as shear thinning uid, and their behavior index ranged from 0.33 to 0.68. Both CNF and SCNF emulsions displayed maximum yield stress at a particle concentration of 0.5wt.% and 0.75wt.%, respectively. Besides, the prepared O/W emulsions using 0.5 to 1.00 wt.% CNF or SCNF did not showed phase separation until 30 days of rest. The data point out to the feasibility of using nanocellulose as a natural emulsi er, which can replace conventional surfactants. Novelty StatementThe wastes biomass from the agriculture and forest activities, are renewable materials currently recognized as a valuable source of energy and chemical products. Cellulose is the main component of lignocellulosic biomass, and it has been converted into value-added materials. Recently, cellulose nanoparticles have been produced to be used as an emulsion stabilizer, replacing conventional surfactants. Nanocellulose particles were successfully generated by means of high-energy ultrasound, an intensive energy process, displaying useful properties to stabilize oil-in-water (O/W) emulsions. Surface properties of cellulose nanoparticles were determined. The equivalent hydrophilic-lipophilic balance for nanoparticles was assessed by comparison with conventional fossil-derived surfactant. The Pickering soya oil-in-water emulsions were very stable, showing their usability as emulsion stabilizers. O/W emulsions display a shear-thinning behaviour.

Thermally Insulating Cellulose Nanofiber Aerogels from Brewery Residues

“…This weight loss occurred due to cellulose degradation through dehydration, depolymerization, and secondary bond cleavage mechanisms. 42 The lower thermal degradation at 281.6 °C and higher solid residue (21.55%) at 599.3 °C were observed for BSG-ABTM5, while the thermal degradation peak of BSG-ABM10 was at 327.3 °C with solid residue (6.01%) at 599.3 °C. The lower thermal stability of TEMPO-treated CNF could be attributed to the smaller dimension of BSG-ABTM5, which can result in a higher surface area.…”

“…A significant weight loss was observed at temperatures between 200 and 320 °C for BSG-ABTM5 and 200 and 360 °C for BSG-ABM10. This weight loss occurred due to cellulose degradation through dehydration, depolymerization, and secondary bond cleavage mechanisms . The lower thermal degradation at 281.6 °C and higher solid residue (21.55%) at 599.3 °C were observed for BSG-ABTM5, while the thermal degradation peak of BSG-ABM10 was at 327.3 °C with solid residue (6.01%) at 599.3 °C.…”

Tailoring Nanostructured Cellulose for Efficient Pickering Emulsions Stabilization

“…Low D [3,2] values are generally associated with higher kinetic stability due to the reduction of the effects of gravitational phase separation, as the droplet separation velocity is proportional to their square radius. [53] Moreover, the droplet size, influenced by the application of HPH mechanical treatment, is known to have an important impact on the rheology of emulsions [42] and, as a consequence, to play a crucial role in controlling the physical properties of emulsions for food, cosmetics, and various industrial applications. Fine emulsions with decreased droplet size and span values have much higher vis-cosities and storage moduli than the corresponding coarse emulsions, as found by Pal.…”

Oil-in-water Pickering emulsions stabilized by nanostructured cellulose: comparison of cellulose nanocrystals and nanofibrils

“…The volume mean diameters D [4,3] were in the range of 1.4-1.8 µm, the surface mean diameters D [3,2] in the range of 1.2-1.4 µm (Table 1). Low D [3,2] values are generally associated with higher kinetic stability because of the reduction of the effects of the gravitational phase separation, this, in turn, is due to the fact that the droplets separation velocity is proportional to the square radius (Martins et al, 2022). In addition, to evaluate the in uence of NCs particle types on the stabilization of emulsion, the surface coverage has been determined, by investigating the relationship between the size of the emulsions as a function of the volume fraction of dispersed phase (i.e.…”