Rheology of the sesame oil-in-water emulsions stabilized by cellulose nanofibers

Macroalgae-derived regenerated cellulose in the stabilization of oil-in-water Pickering emulsions

This study aims to derive regenerated cellulose (RC) from lignin/hemicellulose-free Eucheuma cottonii for its independent stabilization of Pickering emulsion. The RC exhibits a fibrillar morphology with diameters ranging from 17 to 157 nm and stabilizes paraffin oil-Pickering emulsions without any co-stabilizer. It was found that the emulsion stability, viscosities and viscoelasticity correlate positively with RC concentration. All emulsion samples depict gel-like behavior. Under different oil fraction at a constant RC concentration, anomalies were found in emulsion properties. This can be attributed to the aggregating behavior of RC at the oil-water interface, the degree of gel-like structure formation due to materials interaction within the emulsion system, and the variations of microscopic droplet cluster interactions under shear condition. The emulsions portrayed excellent robustness against harsh salinity, high temperature and extreme pH fluctuation. Hence, these findings had elucidated the plausibility of macroalgae-derived RC in enhanced oil recovery application.

Starch nanocrystals as the particle emulsifier to stabilize caprylic/capric triglycerides-in-water emulsions

Starch nanocrystals (SNCs) grafted with octenyl succinic anhydride (OSA) were used to stabilize caprylic/capric triglycerides (GTCC)-in-water emulsions. The morphology and viscoelasticity of emulsions were studied in terms of particle loadings and degrees of substitution (DSs). It is found that the emulsifying capacities of SNCs increase with increased DSs. Both the pristine SNC and modified ones can be well used to stabilize emulsions, whereas the emulsification follows different mechanisms. The platelet-like structure of SNCs, together with its improved amphiphilicity after surface treatments, are important to the formation and evolution of droplet clusters. The deformation and relaxation of those clusters result in weak flow overshoots and strong thixotropy in different shear flow fields, which favor storage and applications of GTCC-in-water emulsions as hydrocolloids. The mechanisms were then discussed in terms of rigidity of SNC and relaxations of clusters. This work proposes a promising application of SNC in food and cosmetic industries.

Cellulose nanofibers reinforced biodegradable polyester blends: Ternary biocomposites with balanced mechanical properties

Blending two biodegradable aliphatic polyesters with complementary bulk properties is an easy way of tuning their final properties. In this work, the ductile poly(butylene succinate) was mixed with polylactide, and as expectable, the blends show improved toughness with sharply reduced strengths. The pristine cellulose nanofibers were then used as the reinforcement for the blends. It is found that most nanofibers are dispersed in the polylactide phase because polylactide has better affinity to nanofibers, and the lower viscosity level of polylactide also favors driving nanofibers into the continuous polylactide phase during melting mixing. In this case, the strength and rigidity losses resulted from the presence of soft poly(butylene succinate) phase are compensated to some extent. To further improve mechanical properties, a two-step approach (reactive processing of blends, followed by the incorporation with nanofibers) was developed. This work provides an interesting way of fabricating fully biodegradable composites with well-balanced mechanical performance.

Effect of NaCl concentration on stability of a polymer–Ag nanocomposite based Pickering emulsion: validation via rheological analysis with varying temperature

Schematic for the impact of NaCl on droplet stabilization in Pickering emulsions.

Use and Understanding of the Role of Spontaneously Formed Nanocellulosic Fiber from Lime (Citrus aurantifolia Swingle) Residues to Improve Stability of Sterilized Coconut Milk

Feasibility of using nanocellulosic fiber (NF) from lime residues as a stabilizer for oil-in-water emulsion was investigated. One-step process to simultaneously prepare an emulsion and NF is proposed. NF could spontaneously form by adding appropriately prepared fiber powder into the test emulsion viz. coconut milk, which was subsequently subject to homogenization and sterilization. Properties of the samples, that is, microstructure, rheological properties, emulsion stability, and color, after sterilization and after 8-week storage at 30 °C were determined. Sterilized samples exhibited pseudoplastic behavior. Samples containing higher NF concentrations exhibited higher viscosity; viscosity remained constant throughout the whole storage period. High emulsion stabilities (>97%) were observed for samples containing 0.4 to 0.8% (w/v) of NF. L^* , C^* , and h^* of the samples were 79 to 80, 8 to 10, and 90, respectively. Three-dimensional network of NF (diameters < 50 nm) attached to fat globule surfaces formed during homogenization is postulated to help stabilize the emulsions. PRACTICAL APPLICATION: One-step process to simultaneously prepare oil-in-water emulsion as well as nanocellulosic fiber (NF) is proposed. Such a formed NF can serve as natural ingredient to stabilize the emulsion. The proposed procedures should be of great interest to an industry producing oil-in-water emulsions (for example, canned coconut milk) that is looking for a natural alternative to synthetic stabilizer.