Search Results (7)

Driven by growing environmental concerns and regulations, cosmetic companies are seeking reliable methods to promptly assess the possibility of replacing high-impact ingredients with sustainable alternatives. In this work, we exploited rheological and texture analyses to evaluate the possibility of using natural and biodegradable raw materials for reformulating three commercial oil-in-water skin care emulsions from an eco-design perspective. Synthetic texturizers, like nylon-12 and PMMA, were replaced with starch, maltodextrin, and silica, while acrylic rheological modifiers were substituted with polysaccharide associations of sclerotium gum, xanthan gum, diutan gum, and carrageenan. Plant-based emollients and a biodegradable elastomer were used as alternatives to silicone oils. The flow and viscoelastic properties of the samples were characterized using rheological tests under continuous and oscillatory flow conditions. The immersion/de-immersion texture analysis allowed us to measure the mechanical properties of firmness, adhesiveness, and stringiness. A double-blind sensory test assessed the products’ application and sensory characteristics. The results revealed that rheology and texture analysis are complementary and correlated techniques, useful for predicting cosmetics’ sensory characteristics. While perfect replication of the original formulas might not be achievable, this protocol can aid formulators in selecting new eco-friendly ingredients ensuring the products’ desired application and sensory properties without compromising consumer experience. Full article

The chemically synthesized polymer polyacrylamide (HPAM) has achieved excellent oil displacement in conventional reservoirs, but its oil displacement is poor in extreme reservoir environments. To develop a biopolymer oil flooding agent suitable for extreme reservoir conditions, the viscosity changes and rheological properties of three biopolymers, diutan gum, xanthan gum, and scleroglucan, were studied under extreme reservoir conditions (high salt, high temperature, strong acid, and alkali), and the effects of temperature, mineralization, pH, and other factors on their viscosities and long-term stability were analyzed and compared. The results show that the three biopolymers had the best viscosity-increasing ability at temperatures of 90 °C and below. The viscosity of the three biopolymers was 80.94 mPa·s, 11.57 mPa·s, and 59.83 mPa·s, respectively, when the concentration was 1500 mg/L and the salinity 220 g/L. At the shear rate of 250 s⁻¹, 100 °C~140 °C, scleroglucan had the best viscosification. At 140 °C, the solution viscosity was 19.74 mPa·s, and the retention rate could reach 118.27%. The results of the long-term stability study showed that the solution viscosity of scleroglucan with a mineralization level of 220 mg/L was 89.54% viscosity retention in 40 days, and the diutan gum could be stabilized for 10 days, with the viscosity maintained at 90 mPa·s. All three biopolymers were highly acid- and alkali-resistant, with viscosity variations of less than 15% in the pH3~10 range. Rheological tests showed that the unique double-helix structure of diutan gum and the rigid triple-helix structure of scleroglucan caused them to have better viscoelastic properties than xanthan gum. Therefore, these two biopolymers, diutan gum, and scleroglucan, have the potential for extreme reservoir oil displacement applications. It is recommended to use diutan gum for oil displacement in reservoirs up to 90 °C and scleroglucan for oil displacement in reservoirs between 100 °C and 140 °C. Full article

Nanomaterials have great potential to influence the properties of cement-based materials due to their small particle size and large specific surface area. The influences of Nano-SiO₂ (NS), gamma-nano-Al₂O₃ (GNA), alpha-nano-Al₂O₃ (ANA), and nano-TiO₂ (NT) on the rheology and hydration kinetics of class G cement at 30 °C were investigated in this study. The nanomaterials were added in dry powder form at dosages of 1, 2, 3, 5, and 7% by weight of cement (bwoc), and their dispersion was accomplished using polycarboxylate superplasticizer (PCE) at a dosage of 1.6% bwoc. PCE provides a uniform dispersion of nanoparticles in the cement matrix, enhancing the efficiency of nanomaterials. The w/c ratio varied between 0.718 and 0.78 to form a constant-density slurry of 1.65 g/cm³. Our test results showed that NS and GNA caused significant increases in the rheology of the cement slurry, with this effect increasing with dosage, while ANA and NT tended to reduce the rheology of the slurry. Compared to a well-suspended and well-dispersed cement slurry generated by the use of PCE and diutan gum, all nanomaterials can accelerate early hydration by reducing the induction time, with GNA having the strongest influence, while NS was the only nanomaterial that further increased the long-term hydration heat release at 7 days. The stronger effect of NS and GNA on the cement slurry properties can be attributed to their higher chemical reactivity. The dosage effect on total hydration extent was relatively strong for ANA, NT, and NS from 3% to 5% but weak for GNA in the range from 3% to 7%. Full article

Maintaining insoluble plant-based ingredients in suspension and ensuring long-term physical stability is particularly challenging for formulators of green cosmetics. This study aimed to evaluate the structure and applicative properties of gel and gel-cream topical formulations suitable for delivering an insoluble phytocomplex on the vaginal mucosa and maintaining its integrity. For this purpose, we studied the compatibility of Perilla frutescens (L.) Britton phytocomplex (PFP), derived from in vitro plant cell cultures and presented as a powder finely dispersed in glycerin, with different classes of natural rheological modifiers (such as xanthan gum, sclerotium gum, succinoglycan, xyloglucan, diutan gum, hydroxypropyl guar gum derivative) in gel and gel-cream formulations, to meet the needs of the cosmetic market for naturalness and biodegradability. Through rheological and texture analyses, we studied the physico–mechanical properties of the samples, comparing the performances of the chosen polysaccharides to those of acrylic polymeric rheological modifiers, evaluating their contribution in terms of stability and applicative properties. Since a weak-gel rheological pattern proved to be the optimal one to keep the actives in suspension, the associations of tamarind seed polysaccharides with succinoglycan or scleroglucan were the most suitable for the formulation of mucoadhesive gels. Full article

The genus Sphingomonas was established by Yabuuchi et al. in 1990, and has attracted much attention in recent years due to its unique ability to degrade environmental pollutants. Some Sphingomonas species can secrete high-molecular-weight extracellular polymers called sphingans, most of which are acidic heteropolysaccharides. Typical sphingans include welan gum, gellan gum, and diutan gum. Most sphingans have a typical, conserved main chain structure, and differences of side chain groups lead to different rheological characteristics, such as shear thinning, temperature or salt resistance, and viscoelasticity. In petroleum production applications, sphingans, and their structurally modified derivatives can replace partially hydrolyzed polyacrylamide (HPAM) for enhanced oil recovery (EOR) in high-temperature and high-salt reservoirs, while also being able to replace guar gum as a fracturing fluid thickener. This paper focuses on the applications of sphingans and their derivatives in EOR. Full article

Microfluidization is a preparation method that can be used to obtain emulsions with submicron droplet sizes. The first objective of this study was to evaluate the influence of homogenization pressure and cycles on droplet sizes using response surface methodology. Secondly, the influence of the diutan gum concentration incorporated in the optimized emulsion on rheological properties, microstructure, and physical stability was investigated. Taking the response surface analysis into account, the emulsion processed at 20,000 psi after four cycles seemed to show the smallest Sauter diameter values. Hence, this emulsion was the starting point to incorporate diutan gum. Interestingly, the formation of a 3D network in the emulsion, observed by FESEM, was provoked by diutan gum. The emulsion formulated with 0.4 wt.% of diutan gum presented rheological gel properties and enhanced physical stability. This work highlights the importance of selecting optimized processing variables using the microfluidization technique and extends the knowledge of using diutan gum in combination with zein. Full article

The rheological properties exhibited by gums make its use in applications interesting, such as foods, cosmetics, enhanced oil recovery, or constructions materials. Regardless of application field, the effect of temperature on these properties is of great importance, since these properties can be modified and cause the gum not to be useful for those conditions. Diutan and rhamsan gums are biopolymers, belonging to the sphingans, with similar structures which differ in the substituents of their side chains. It is known that both gums exhibit suitable viscoelastic properties and flow behavior when used as a stabilizer, gelling agent, or thickener. Both gums are widely used in food industry, personal care products, construction materials, oil operations, etc. For this reason, to know the effect of the temperature on their rheological properties is very helpful. For this purpose, small amplitude oscillatory shear measurements and flow curves, as a function of the temperature from 10 °C to 60 °C, have been performed, and the results obtained for both gums compared. The obtained results provide interesting information from an industrial point of view, since they reveal that the rheological properties remained almost unaltered in the temperature range assessed with diutan gum aqueous solutions, being slightly more viscous and viscoelastic than rhamsan gum solutions. Full article