Rheological Properties Research Articles

The Assessment of Physicochemical and Antimicrobial Properties of Hydrophilic Gels Containing Tetracycline Hydrochloride and Various Concentrations of Ethanol.

The high prevalence of acne, which affects nearly 85% of adolescents and young adults, underscores the importance of exploring new therapeutic solutions. The aim of the present study was to design a stable hydrogel formulation containing tetracycline hydrochloride (TC) in the presence of ethanol at various concentration levels. The antibiotic stability was assessed over a period of 84 days using the HPLC method. The rheological properties of the formulations and their microbiological activity were also evaluated. Hydrogels without ethanol and those containing 5% and 25% alcohol showed similar rheological properties and high stability of the antibiotic throughout the observation period. The formulation with the highest ethanol content of 50% differed significantly from the others in terms of rheological properties. Although the flow and viscosity curves were like those of the other formulations, the viscosity values were significantly lower. The stability of tetracycline in this formulation was also significantly lower, and by the 84th day of observation, the concentration of the drug had decreased to almost 45% of its initial content. The formulations containing the highest concentration of ethanol displayed the highest activity against the biofilm of the acne-causing agent, Cutibacterium acnes. The study demonstrated the possibility of developing stable and antimicrobial effective hydrogel formulations with tetracycline and ethanol as a substance enhancing drug penetration into the hair follicles.

Furcellaran: Impact of Concentration, Rheological Properties, and Structure on Ice Recrystallization Inhibition Activity.

Recrystallization is considered the main damaging mechanism during the frozen storage of biologic materials. In this study, furcellaran, a polysaccharide related to κ-carrageenan, was studied for its concentration-dependent effect on ice crystal growth and recrystallization. The structure and sulfate content of the utilized furcellaran was analyzed by 1H nuclear magnetic resonance spectroscopy, ion chromatography, and high-performance size-exclusion chromatography. Additionally, the rheological properties of furcellaran solutions were investigated. Our findings demonstrate that furcellaran inhibits ice growth as effectively as κ-carrageenan. Furthermore, the rheological properties change with increasing furcellaran concentration, resulting in a gel-like consistency at 5 g/L, which coincides with decreased recrystallization inhibition activity and larger crystals. This suggests that gel formation or a gel-like consistency has to be avoided for optimal recrystallization inhibition activity.

Formation of tannic acid-binding ovalbumin amyloid fibril hydrogels: Enhanced antibacterial and antioxidant properties

The protein-induced amyloid fibrils (AFs) are limited in food industry due to their poor antioxidant and antibacterial activities. However, polyphenol shows the potential functional modifications of AFs, and extend their application in food processing. In present study, tannic acid-binding ovalbumin-induced AFs (TA-OAFs) hydrogels were fabricated via different concentrations of TA and ovalbumin amyloid fibrils, and the rheological properties, thermal stability, and morphology of the hydrogels were investigated. Then, the physiochemical, antioxidant, and antibacterial of TA-OAFs hydrogels were further analyzed. The obtained results indicated that the addition of TA could increase the average diameter of nanofibrils with increased β-sheet contents, and showed a TA concentration-dependent tendency. Moreover, TA-OAFs hydrogels also possessed better thermal stability, antioxidant activity, and antibacterial capacity for both Gram-negative and Gram-positive bacteria. The present study might contribute to a better understanding of antimicrobial materials designing of protein-induced amyloid fibrils in the food field with beneficial properties.

Clay Minerals and Biopolymers in Film Design: Overview of Properties and Applications

Research to replace petroleum-based plastics has been quite challenging. Currently, there is a lot of interest in biopolymers as an alternative. However, biopolymers do not have suitable mechanical properties when in film form, which limits their applications. To resolve this issue, clay minerals are being incorporated as a strategy. Clay minerals offer the films good barrier, thermal, rheological, optical, and mechanical properties. They can also work with other additives to promote antioxidant and antimicrobial activity. This brief review focuses on incorporating clay minerals with other nanofillers and bioactives to improve their physical, chemical, and functional characteristics. The synergy of these materials gives the films exceptional properties and makes them suitable for applications such as food coatings, packaging materials, dressings, and bandages for treating skin wounds.

Impact of Germination Treatment and Quinoa Variety on the Physicochemical and Rheological Properties of Wheat Dough

Impact of Germination Treatment and Quinoa Variety on the Physicochemical and Rheological Properties of Wheat Dough

Maleic anhydride-functionalized cellulose nanocrystal-stabilized high internal phase Pickering emulsion for pesticide delivery

The salt-responsiveness of Pickering emulsions has significantly influenced their applications due to the large amount of salt on the surface of plant leaves. The present study provided a maleic anhydride-functionalized cellulose nanocrystal-stabilized high internal phase Pickering emulsion (MACNCs-HIPPEs) that was stable to high-concentration salt and used for pesticide delivery. The stability of MACNCs-HIPPEs was investigated by adjusting the oil-phase volume fraction (φ), the MACNCs concentration, NaCl dosages, and the rheological properties. The high internal phase Pickering emulsion was obtained at φ of 0.8 and MACNCs concentration of 2wt% and showed excellent salt stability (NaCl, 1200 mM) and significant storage stability (60 days). The sustained release of imidacloprid (IMI) from imidacloprid-loaded MACNCs-HIPPEs (IMI@MACNCs-HIPPEs) showed a positive correlation to the temperature (15°C, 25°C, 35°C), indicating clear thermo-responsiveness of the prepared pesticide formulation. The test of spread and retention of IMI@MACNCs-HIPPEs on the leaf surface showed a significant advantage compared with the commercial IMI water dispersible granules (CG). All the advantages mentioned above showed the excellent potential of the MACNCs-HIPPEs in delivering lipophilic pesticides.

Novel Hydrogels Based on the Nano-Emulsion Formulation Process: Development, Rheological Characterization, and Study as a Drug Delivery System.

In this study, we present a new type of polymer-free hydrogel made only from nonionic surfactants, oil, and water. Such a system is produced by taking advantage of the physicochemical behavior and interactions between nonionic surfactants and oil and water phases, according to a process close to spontaneous emulsification used in the production of nano-emulsions. Contrary to the classical process of emulsion-based gel formulation, we propose a simple one-step approach. Beyond the originality of the concept, these nanoemulgels appear as very promising systems able to encapsulate and deliver various molecules with different solubilities. In the first section, we propose a comprehensive investigation of the gel formation process and its limits through oscillatory rheological characterization, characterization of the sol/gel transitions, and gel strength. The second section is focused on the follow-up of the release of an encapsulated model hydrophilic molecule and on the impact of the rheological gel properties on the release profiles.

THE FRACTAL RHEOLOGY OF MAGNETORHEOLOGICAL ELASTOMERS DESCRIBED THROUGH THE MODIFIED ZENER MODEL AND THE COLE–COLE PLOT

The main objective of this study focuses on using, for the first time, the Cole–Cole semilogarithmic fractal plot to study the fractal rheological behavior of magnetorheological elastomer materials using the fractional Zener model. Experimental data and theoretical results show that the Cole–Cole semilogarithmic fractal plot predicts the Zener mathematical model’s material parameters. This paper elucidates the benefits of using Cole–Cole semilogarithmic fractal plots to accurately predict material rheological properties of composite elastomer reinforced with nano or microiron particles observed during experimental tests.

Improvement of O/W emulsion stability and rheological properties by highly branched cyclic dextrin and preparation of a novel emulsion gel

The objective of this study was to formulate and investigate a low-oil emulsion gel (20%, v/v) stabilized by highly branched cyclic dextrin (HBCD). The results indicated that HBCD effectively prevented the coalescence of oil droplets when the concentration reached a specific threshold (40 wt%). All samples exhibited dense network structure and elastic solid properties when stored at 4 °C. Fluorescence images showed the oil droplets tended to be irregular after refrigeration, indicating HBCD molecules aggregated under low temperature. Fourier transform infrared spectroscopy and its deconvolution results displayed a shift in the hydroxyl peak and an increase in R1046/1022. Additionally, new crystalline peaks emerged at 17° and 22° in the X-ray diffusion spectra of recrystallized HBCD samples. It suggested the hydrogen bonds and ordered structure of HBCD were increased in the emulsion gels during storage. Therefore, the formation and orderly arrangement of double helix structures of the branched chains which stabilized by hydrogen bonds promoted the recrystallization and self-assembly of HBCD, ultimately resulting in the formation of a stable gel structure. The research provided theoretical feasibility for the development of structured emulsions for functional foods.

Effects of cellulose nanofibrils on rheological and mechanical properties of 3D printable cement composites

This study explores the effects of cellulose nanofibrils (CNF), a relatively new type of nanocellulose material, on the rheological and printability characteristics of cementitious mixtures, and the mechanical properties of 3D printed specimens. The rheology of the mortar mixtures with varying ratios of CNF is thoroughly assessed first. Two testing protocols, stress growth test and ramp test, are followed for rotational measurements using a shear rheometer with a building cell and vane motor. Stress growth tests are carried out to quantify the static yield stress of the cementitious mixtures. Ramp tests are conducted to determine dynamic yield stress and plastic viscosity of the mixes using the Bingham visco-plastic material model. As oscillatory measurements, amplitude sweep tests are carried out to determine the viscoelastic properties of the mortar mixes, including storage modulus and critical strain that are found to be essential for buildability. Thermogravimetric analysis (TGA) is conducted to assess the effects of CNF on the hydration characteristics of the mixtures. The printability and the buildability of the mortar mixtures incorporating CNF are assessed using a 3D concrete printer equipped with a 10 mm diameter nozzle and screw pump mechanism. Tensile, flexural, and compressive strength tests are conducted to determine the mechanical properties of 3D printed specimens with varying ratios of CNFs. Scanning electron microscopy (SEM) is used to conduct the microstructural analysis on fractured surfaces of the mechanically tested specimens. Results indicate that adding CNF at least 0.3 wt% of cement has a favorable effect on the rheological properties of cement composites.

Exploring the potential of supramolecular hydrogels as advanced bioinks for bioprinting and biomedical applications

Supramolecular hydrogels have emerged as versatile bioinks in tissue engineering, providing a promising avenue for constructing intricate and functional biological structures. This paper explores the significance of employing supramolecular hydrogels as advanced bioinks for three-dimensional bioprinting and various biomedical applications. Supramolecular hydrogels possess distinct and tunable characteristics attributed to the dynamic nature of supramolecular host–guest interactions alongside interactions based on DNA and peptides, which increases their significance in tissue engineering. These interactions are essential for enhancing the mechanical properties, injectability, printability, post-printing stability, and biocompatibility of hydrogels. Gelation kinetics and rheological properties can also be manipulated to suit specific printing techniques. Furthermore, these supramolecular interactions facilitate the incorporation of bioactive molecules to regulate cellular behavior and tissue development. These diverse interactions observed in supramolecular hydrogels underscore their ability to emulate the dynamic and responsive nature of the cell’s extracellular matrix, which fosters cell growth, adherence, and differentiation. This review specifically highlights the cucurbit[n]uril and cyclodextrin-based host–guest supramolecular hydrogels, as well as peptide and DNA-based supramolecular structures as advanced bioinks and brief examples of their applications in various biomedical fields. These advanced bioinks would drive the development of intricate tissue constructs with enhanced biomimicry and therapeutic potential in regenerative medicine.

Extrusion foaming of Poly(lactic acid)/Rice straw composites: Opposing effects of eco-friendly physical/chemical treatment and compatibilization methods

In this study, the effects of two environmentally-friendly pulping methods along with two different reactive compatibilization methods on the foamability of poly (lactic acid) (PLA)/rice straw (RS) biocomposites have been investigated. RS as an annually renewable agricultural waste is low-cost and available. Melt-compounding and melt-foaming processes were performed through a twin-screw extrusion processing. The correlations between processing and microstructure were studied. The findings show that the RS pulping with sodium bicarbonate (SB) solution leads to the lignocellulosic particles with a porous structure. The structure causes the filler/matrix mechanical engagement and improves the interfacial adhesion and rheological properties, hence forming smaller cells with the narrowest cell size distribution. In contrast, applying ultrasound waves on the RS pulp brings the particles to very smooth surfaces. These surfaces have the highest activity at the cell nucleation stage and considerably increase the foam’s cell density. The reactive compatibilizers based on epoxy and maleic anhydride groups show opposing effects on the biocomposite microstructure, depending on the RS pulp type. The use of the reactive compatibilizers in the PLA/RS pulp treated with SB led to lighter foams with larger cells and higher cell densities and void fractions. Whereas the incorporation of the compatibilizers into the biocomposites containing RS pulp treated with SB and ultrasonic waves resulted in noticeably lower cell density and larger foam density. The extruded biocomposite foams with closed-cell microstructure can be used in insulation and packaging applications.

The influence mechanism of bitumen components on its macroscopic and microscopic properties: Analysis based on polyphosphoric acid modification

In order to investigate the impact of bitumen components on its overall properties, various modified bitumen with 1.0 %PPA or 2.0 %SBS/SBR + 0.6 %PPA were prepared. The influence of PPA dosage on bitumen’s physical properties were evaluated, and the macroscopic and microscopic properties of each bitumen sample were characterized by DSR, BBR and atomic force microscopy observation. The components of bitumen were separated through SARA test, and the infrared spectroscopy of asphaltenes was further analyzed. The findings suggest a significant impact on bitumen with PPA incorporation, the elastic recovery properties of bitumen at high temperatures were enhanced due to a more stable colloidal structure was formed by the dispersion and interaction of macromolecular asphaltenes. However, the low-temperature rheological properties of bitumen were impaired by reason of a relatively reduced flowable lightweight component. Specifically, the large asphaltenes clusters were dispersed cause PPA reacted with the –OH bonds of alcohols in bitumen by phosphorylation. By modeling the correlation between bitumen component contents and its microscopic surface parameters, the asphaltenes decomposition was demonstrated to be an important factor on the microscopic morphology, which was also related to the content of saturates and aromatics. Thus, a method for deconstructing bitumen from a compositional perspective is proposed.

Quality analysis of dough and steamed bread under various freezing conditions.

Freezing is a crucial step in the process of frozen foods. In this study, the effects of different freezing methods, including liquid nitrogen immersion freezing (LF), quick-freezing machine freezing (QF), packaging immersion freezing (PF), and ultralow temperature refrigerator freezing (UF), and freezing time (0, 15, 30, and 60 days) on the textural properties, dynamic rheological properties, water distribution, and structure of dough and the quality of end steamed bread were evaluated. Freezing resulted in a decline in the physicochemical properties of dough. UF- and QF-doughs had higher storage modulus and loss modulus, compared with PF- and LF-doughs. LF enhanced the textural attributes of the dough, resulting in reduced hardness and increased springiness. At 15 days of freezing, QF- and LF-doughs exhibited a compact and continuous structure with a smooth surface. Additionally, the correlation analysis elucidated that the weight loss rate and the bound water content of the dough had discernible impacts on the texture of both the dough and the resulting steamed bread. Overall, LF demonstrated a relatively high freezing efficiency and effectively maintained the quality of the dough for up to 15 days of freezing. These results offer valuable insights for the applications of freezing methods and time in frozen foods.

Effects of Aging on Rheological Properties and Microstructural Evolution of SBS Modified Asphalt and Crumb Rubber Modified Asphalt Binders

Focusing on the comparison of aging resistance between styrene-butadiene-styrene (SBS) modified asphalt (SBSMA) and crumb rubber modified asphalt binders (CRMA), the influences of aging on rheological properties and microstructural characteristics of different modified asphalts were investigated in this work. Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) tests were carried out, and the variations in rheological properties for different modified asphalts after the rotating thin film oven test (RTFOT) were analyzed with the rutting factor aging index (RAI) and creep rate aging index (CAI). By using Fluorescence microscopy (FM) and Fourier transform infrared (FTIR) spectroscopy, the evolutions of microstructure and chemical composition for two modified asphalts were analyzed with carbonyl index growth rate (CIR) and sulfoxide index growth rate (SIR). Then, The relationships between CIR/SIR and RAI/CAI were established to show the correlation between the deterioration of macroscopic performance and the evolution of micro-structure. The results indicated that the aging degree of asphalt increases with elevated temperatures, leading to decreasing low-temperature performance while improving high-temperature performance. Nevertheless, SBSMA exhibited strong sensitivity to aging temperature. Under thermo-oxidative aging, the RAI and CAI of SBSMA were lower than those of CRMA, whereas the regularities of CIR and SIR were opposite, indicating that CRMA was superior to SBSMA in terms of anti-aging properties due to the rupture of the cross-linked network structure of SBSMA. However, CRMA experienced aging accompanied by full swelling, and thus, relatively minor performance declined. The CIR and SIR exhibited a better correlation with the RAI and CAI, illustrating that both CIR and SIR could characterize the aging degree of modified asphalts well.

Nano-hydroxyapatite Pickering emulsions as edible mayonnaise-like food sauce templates: A novel approach for food design

Pickering emulsions have the potential to enhance product stability and provide opportunities to create functional solutions that align with labelling requirements. The present work aims to develop Pickering emulsions stabilised by nano-hydroxyapatite (n-HAp) particles to replace traditional mayonnaises. The study addresses the effect of n-HAp solid particle concentration (5–15 wt%) and oil-water ratio (50:50, 60:40, 70:30, and 80:20, v/v) on emulsion stability, rheological properties, and oxidative stability. The results indicate that the produced Pickering emulsions have good stability for the tested period of 90 days, except for the 80:20 o/w emulsion that undergone a prompt quick phase separation. The Pickering emulsions produced with higher n-HAp concentration or oil content have a semi-solid structure, rendering them desirable options for replicating the texture of traditional mayonnaises. Regarding oxidative stability, the Pickering emulsions showed considerably improved stability compared to commercial mayonnaises (∼13 times higher), suggesting higher resistance to peroxidation and a longer shelf-life.

Study on the application and performance of liquid crystal emulsion system in sunscreen products

ABSTRACT Liquid crystal (LC) emulsion is a new emulsion system which has excellent application potential in the field of cosmetics. In this study, the LC emulsifier and traditional emulsifier were used to prepare the emulsions containing different types of sunscreen agents, respectively. The microstructure, sunscreen performance and rheological properties of the emulsions were studied systematically. The results showed that the formation of LC structure was not affected by sunscreen agents. LC structure can also enhance the sunscreen property of the emulsion as well as improve the sensory property. Further, we combined different sunscreen agents to prepare LC sunscreen emulsion. The sunscreen performance and repair effectiveness of emulsion were evaluated by human test. The results showed that LC sunscreen emulsion has an increased SPF value from 56 to 70 compared to non-LC sunscreen emulsion. Meanwhile, the LC structure also enhanced the moisturising properties of the emulsion, and the TEWL value of LC emulsion and non-LC emulsion was 67.4% and 96.5%, respectively. In addition, LC sunscreen emulsion has higher safety and better storage stability. In conclusion, this study provided the practical application of LC emulsion systems as well as the important guidance for developing excellent sunscreen emulsions.

Sustainable pectin-based film for carrying phenolic compounds and essential oil from Citrus sinensis peel waste

Currently, food science faces the challenge of finding methods to deliver functional and nutritional compounds in ready-to-eat products. Biopolymeric films enriched with essential oils are an emerging strategy for incorporating valuable components into edible carrier matrices. This study investigated the wastewater from orange peel hydrodistillation as a source of phenolic compounds and an innovative ingredient to develop bioactive limonene-loaded pectin-based films, addressing waste disposal challenges by developing a multi-functional packaging material. The objective was to evaluate the effects of formulation synergies, particularly pectin-phenolic interactions, on the physicochemical, rheological properties, and essential oil retention capacity of film-forming emulsions, and then assess the effects on the physicochemical and mechanical properties of the films. Films were analyzed for morphology, water vapor permeability, light transmittance, mechanical, chemical, and physical properties, and encapsulation efficiency. Three formulations were evaluated: pectin control (PC), pectin with Tween-80 surfactant (PT), and pectin with phenolic-rich wastewater (PPW). PPW emulsions displayed higher viscosity, consistency, kinetic stability, and essential oil retention compared to PC. The resulting environmentally-friendly films exhibited increased thickness, improved oil droplet distribution, a more crystalline structure, lower clarity, better flexibility, and increased water vapor permeability. Altered FTIR spectrum bands suggested potential pectin-phenolic interactions, influencing film physicochemical properties through mechanisms such as enhanced crosslinking. The PT film-forming emulsion demonstrated lower kinetic stability and less homogeneity than PC and PPW, showing that the use of the commercial surfactant (0.1g/100 g of film-forming emulsion) led to less favorable performance in terms of emulsion stability and film properties compared to PPW and PC. Conclusively, utilizing orange residue for bioactive pectin-based films offers valuable insights for promoting shelf life, reducing the need for formulation surfactants, and adding nutritional value in food applications, while simultaneously repurposing underutilized waste. This research also contributes to insights into the development of more stable emulsions for creating uniform films.

Improved and Highly Reproducible Synthesis of Methacrylated Hyaluronic Acid with Tailored Degrees of Substitution.

Methacrylated hyaluronic acid (HAMA) is a versatile material that has gained significant attention in various pharmaceutical and biomedical applications. This biocompatible material can be photo-cross-linked in the presence of Irgacure 2959 (I2959) to produce hydrogels. Controlling the degree of methacrylation (DM) is crucial since it plays a pivotal role in determining the properties and thus the potential applications of the gels. We report herein a new green approach for the highly controlled and tailored modification of hyaluronic acid (HA) with methacrylic anhydride (MA). The reaction conditions of previously reported procedures were optimized, leading to a decreased reaction time (3 h instead of 24 h) and consumption of fewer equivalents of MA (5 equiv instead of 20) and water as the sole solvent. By changing the amount of base added, HAMA with three different DMs was obtained: 19, 35, and 60%. The influence of the molecular weight of HA, degree of substitution, and concentration of the HAMA solution prior to photo-cross-linking on the rheological, swelling, and degradation properties of HAMA hydrogels was also studied in this work.

Organosiloxane-Modified Auricularia Polysaccharide (Si-AP): Improved High-Temperature Resistance and Lubrication Performance in WBDFs.

This study introduces a novel organosilicon-modified polysaccharide (Si-AP) synthesized via grafting and comprehensively evaluates its performance in water-based drilling fluids (WBDFs). The molecular structure of Si-AP was characterized using Fourier-transform infrared spectroscopy (FTIR) and 1H-NMR experiments. Thermalgravimetric analysis (TGA) confirmed the good thermal stability of Si-AP up to 235 °C. Si-AP significantly improves the rheological properties and fluid loss performance of WBDFs. With increasing Si-AP concentration, system viscosity increases, API filtration rate decreases, clay expansion is inhibited, and drilling cuttings hydration dispersion is suppressed, especially under high-temperature conditions. Additionally, mechanistic analysis indicates that the introduction of siloxane groups can effectively inhibit the thermal degradation of AP chains and enhance their high-temperature resistance. Si-AP can form a lubricating film by adsorbing on the surface of clay particles, improving mud cake quality, reducing the friction coefficient, and significantly enhancing the lubricating performance of WBDFs. Overall, Si-AP exhibits a higher temperature-resistance limit compared to AP and more effectively optimizes the lubrication, inhibition, and control of the filtration rate of WBDFs under high-temperature conditions. While meeting the requirements of drilling fluid systems under high temperatures, Si-AP also addresses environmental concerns and holds promise as an efficient solution for the exploitation of deep-seated oil and gas resources.