Viscosity Recovery Research Articles

Fabrication of novel polysaccharides and glycerol monolaurate based camellia oil composite oleogel: Application in wound healing promotion

In this study, a novel camellia oil composite oleogel (SX@G-CO) was prepared by a combination of direct dispersion and emulsion-templated methods using polysaccharides (sodium alginate and xanthan gum, ratio in 4:6) as oleogelators and glycerol monolaurate (GML, 7 wt%) as gel-enhancer. The comparative experiments revealed that the polysaccharides could effectively enhance the densification of the three-dimensional network structure of the oleogel through hydrogen bonding and electrostatic interactions, and significantly improve its thermal stability, rheological properties (adhesive strength 49,243.6 mPa•s, viscosity recovery rate 94.6 %) and oil binding capacity (80.6 %). The introduction of GML further enriched the crystal diversity of the oleogel and imparted excellent antimicrobial ability (nearly 100 % inhibition effect on E.coli). Furthermore, the in vitro experiments demonstrated that the synergistic effect of polysaccharides and GML significantly enhanced the anti-inflammatory, antioxidant, cell migration and proliferation abilities of SX@G-CO oleogel compared with GML-CO and SX-CO oleogels. In addition, SX@G-CO oleogel has also been demonstrated to effectively promote full-thickness burn healing in mice by reducing bacterial infection and inflammatory response, regulating free radical levels, and promoting neovascularization in vivo, with effects comparable to marketed ointment. SX@G-CO oleogel as a bioactive molecule-polysaccharides composite has potential clinical application in burn wound repair.

Synergistic thickening mechanism of surfactants and supramolecular inclusion systems

The effectiveness of conventional polymer flooding systems for improving oil recovery (IOR) in high-temperature and high-salt reservoirs is greatly limited. The polymer inclusion system forms a spatial network structure through host–guest inclusion, which can achieve the goal of low concentration and high viscosity in high-temperature and high-salt environments. However, there are few reports on further enhancing the performance of polymer flooding systems based on the inclusion system. In this study, the optimal ratio of erucamide propyl betaine (EDAB) to polymer inclusion system (ABMN) was first investigated. The results showed that the optimal formulation for the synergistic enhanced inclusion system was 2000 mg/L ABMN+2000 mg/L EDAB, which could reach 95.7 mPa·s under 85 ℃ and salinity of 32868 mg/L, and the viscosity was more than twice that of the ABMN system. The wormlike micelles (WLMs) formed by EDAB synergistically interacted with the ABMN, resulting in a larger hydrodynamic radius and a denser spatial network structure. Due to the synergistic effect of supramolecular forces, the system has significantly improved its temperature resistance, salt resistance, and shear resistance, with a viscosity recovery rate of up to 98.9 %. This provides a new oil displacement system for IOR in high-temperature and high-salt reservoirs.

3D-printed MOF/MoS2 aerogel for dye adsorption and photocatalytic degradation

The escalating challenge of water resources contamination, attributed to toxic pollutants, requires urgent attention from both governments and society. Furthermore, the inefficacy of conventional water treatment methods emphasizes the critical necessity for exploring the development of affordable, renewable, and high-performance materials, which should, for instance, enable the mutual adsorption and photocatalytic degradation of organic pollutants. Here we employed the 3D printing technique to manufacture an aerogel based on alginate, gelatin, and carboxymethylcellulose incorporated with 5 and 7.5 wt % of MOF/MoS2. FTIR spectra and EDS analysis evidenced the presence of MOF/MoS2 in the structure of the aerogels, while Helium pycnometer analysis and SEM micrographs demonstrated that the aerogels presented low density and a porous structure with porosity above 80 %. The swelling test showed that the aerogels displayed a high water absorption capacity (1400 %) after 70 h of immersion. The rheology test demonstrated that elastic behavior prevails over viscous behavior (G' > G″) and the incorporation of 7.5 wt % MOF/MoS2 favored shear thinning and viscosity recovery in the hydrogel. Adsorption tests to methylene blue (employed as a model) showed that the aerogel (HD) without the presence of MOF/MoS2 and the aerogels HD/MOF/MoS2 5 % and MOF/MoS2 7.5 % showed removal efficiencies of 16.77 %, 28.66 %, and 95.86 %, respectively. Conversely, the photodegradation test showed that HD/MOF/MoS2 5 % and HD/MOF/MoS2 7.5 % had an efficiency of 89 % and HD of 80 %. Therefore, our results demonstrate that the developed aerogels are promising candidates for the adsorption and photodegradation of dye while being low-cost, environmentally friendly, and easy to manufacture.

Rheological characterization and print quality studies of gelatin/collagen I/PEGDA hydrogels

Bioprinting is an up-and-coming technology that uses the basis of additive manufacturing and applies it to the field of tissue engineering. Bioprinting is used to create 3D models of diseased tissue and organs, test cellular responses to drug therapies, and create potentially transplantable organs and vasculature. Bioprinting has gained increasing interest especially in drug discovery, as the traditional 2D cell culture models have been shown to produce results that are not mimicked in animal and human trials. Bioprinters use materials called bioinks, developed from hydrogels which can contain cells and biological factors. While there are commonly used bioinks, there is a need for the development of a diverse range of bioinks for varying applications. In this study, an alternative bioink was developed. The formulations included gelatin, collagen I, and varying amounts of poly (ethylene glycol) diacrylate (PEGDA). These formulations were subject to rheological characterization and print quality analysis. Formulations with higher concentrations of PEGDA had higher degrees of shear-thinning, higher viscosity recovery, lower viscosities, and less dominant gel behavior. The print quality studies showed that the formulations with lower concentrations of PEGDA had better printability, print accuracy, and print fidelity. Formulation P5 had the best overall print quality.

High-Temperature, Salt-Resistant, and High-Strength-Controlled Consolidated Resin Slurry for Fracture Plugging during Oil and Gas Well Drilling

Summary The temperature and pressure of deep and ultradeep plugging are gradually increasing, resulting in higher requirements for the performance of plugging materials. In this study, a resin slurry plugging system that can be used to plug lost channels of fractures of different scales in the process of oil and gas exploitation was prepared, and the factors affecting the consolidation of the system under different conditions were studied. The resin slurry plugging system was initially consolidated in 2 hours and completely consolidated in 6–9 hours. It exhibited good viscosity recovery ability and excellent thixotropy characteristics of shear thinning and static thickening, which help realize strong residence and plugging in the fracture. The resin slurry plugging system prepared with 200 000 mg/L salinity water could still achieve good consolidation at 140°C, and the consolidating strength was higher than 5.0 MPa. In addition, the 7.10-MPa consolidation strength of the resin slurry plugging system with aging at 140°C for 15 days could satisfy the long-term plugging needs. Furthermore, the pressure-bearing plugging capacity and degradability of the resin slurry plugging system were investigated. The resin slurry plugging system could be fully filled in the steel wedge-shaped fractured core at 140°C, and the pressure-bearing plugging capacity was up to 13.07 MPa. The resin slurry plugging system could achieve a strong residence in the sand-filling pipe model, forming a high-strength plugging layer, and the pressure-bearing plugging capacity could reach 10.73 MPa. The acid dissolution degradation rate at 140°C was 97.69%, indicating a low degree of damage to the reservoir and meeting the requirements for subsequent plug removal. The excellent properties of the resin slurry plugging system, such as high temperature, high salt resistance, and pressure plugging, provide a new solution for plugging lost formations of fracture cave carbonate rocks.

The gelation characteristics of Torreya grandis wax in diacylglycerol and its preparation of oleogel substitution for shortening

Torreya grandis wax (TGW), a new nut wax and by-product of refined Torreya grandis oil, lacks sufficient research and application. In this study, the gelling behavior in diacylglycerol (DAG) and chemical compositions of TGW were investigated. Compared with four typical natural waxes, TGW exhibited the lowest critical gelling concentration (Cg, 1 %wt) in DAG. The results performed that TGW-DAG oleogels at Cg possessed the highest G′LVR and G″, highest critical stress, good thermal stability, moderate viscosity recovery, and osc. yields stress, indicating strong gel. The microstructure and correlation analysis revealed that excellent gelling behaviors of TGW-DAG oleogels were due to the solid three-dimensional network formed by rod-like TGW crystal, and the higher hydrocarbon compound (HC) content and HC/wax ester in TGW. Formulation optimization suggested that oleogel containing 3.2 % TGW and 1.0 % diosgenin (DSG) better mimicked the characteristics of shortening in terms of hardness, adhesiveness, spreadability. The bread prepared with TGW/DSG-DAG oleogel owned uniform and dense pores, the best moisture retention capability, and soft and firm taste, demonstrating that TGW/DSG-DAG oleogel was a good shortening substitute. Therefore, this study provides the systematically fundamental knowledge of TGW and develops DSG-TGW-DAG oleogels as promising shortening substitutions.

Performance modulation and optimization of PE fiber reinforced 3D-printed geopolymer

This paper aims to develop an environmentally friendly and low-carbon geopolymer for 3D printing, which has excellent mechanical and rheological performance. The effect of ground granulated blast furnace slag (GGBS), NaOH and sand on mechanical strengths, 3D printing performance and rheological behavior was investigated to determine the optimum mix proportion for 3D-printed geopolymer. Moreover, polyethylene (PE) fibers were introduced to reinforce the performance of 3D-printed geopolymer. Results show that when the ratio of GGBS, NaOH and sand is 1:0.13:2.67, geopolymer exhibits superior mechanical, 3D printing and rheological properties. Increasing the dosage of GGBS and sand leads to an overall increase in the yield stress but a decrease in the consistency coefficient, indicating that it benefits the stacking and fluidity performance of 3D-printed geopolymer. However, with an increase of NaOH content, the stacking performance increases while the fluidity decreases. Although increasing NaOH and sand content benefits the viscosity recovery performance, an increase in GGBS content has an opposite effect. Incorporating PE fibers significantly increases the flexural strength with an increase of up to 27.8 % and 21.3 % in 7-d and 28-d flexural strength, respectively, given a PE fiber volume of 0.6 %. Increasing the volume of PE fibers leads to a significant rise in the stacking performance but a reduction in the fluidity. Furthermore, adding PE fibers negatively affects the geopolymerization but benefits the hydration process given an increase of Si/Al and Si/Ca ratio identified in PE fiber reinforced 3D-printed geopolymer.

Development and performance evaluation of a novel SiO2-enhanced seawater-based temperature-resistant clean fracturing fluid

Hydraulic fracturing has been proposed as a potential technology for the development of low-permeability oil reservoirs and also has promising application prospects offshore. In this study, a novel SiO2-enhanced seawater-based temperature-resistant clean fracturing fluid was formulated. The fracturing fluid main agents, additives and reducing agents were screened. Besides, the physical and chemical properties (rheology) as well as application (i.e., sand-carrying, gel-breaking, dynamic fluid loss, dynamic damage and anti-swelling) performance of the proposed SiO2-enhanced seawater-based temperature-resistant clean fracturing fluid were systematically investigated. It was revealed that 3.2 wt% AASB-17+1.92 wt% NaSal+0.1 wt% SC-107+0.1 wt% TS3 was the optimal SiO2-enhanced seawater-based clean fracturing fluid system formula. The SiO2-enhanced seawater-based temperature-resistant clean fracturing fluid exhibited remarkable rheological characteristics, the temperature and shear resistance was increased by 28 %, with a maximum temperature resistance of 90ºC. This system can be applied to the fracturing development of most oil reservoirs in the Bohai Bay. In addition, the presence of SiO2 nanoparticles significantly improved the sand-carrying properties of the proposed clean fractuirng fluid system. The experimental results also suggested that the SiO2-enhanced seawater-based temperature-resistant clean fracturing fluid showed excellent performance of shear recovery (fixed shear viscosity recovery rate was 100 %), gel breaking (30 min,1 mPa·s), filter loss (Cw=4.75×10−4 m/min1/2), anti-swelling (anti-swelling rate was 77.78 %) and salt tolerance. This study provides fundamental technical support for the application of SiO2-enhanced seawater-based temperature-resistant clean fracturing fluid in offshore fracturing.

Optimizing adhesive rheology for stencil printing of fuel cell sealings using supervised machine learning

In a single low-temperature proton exchange membrane fuel cell (LT-PEMFC) stack, the sealings are responsible for preventing leakages, providing electrical insulation and compensating assembly tolerances. This study investigates stencil printing to produce fuel cell sealings and aims to identify reliable conditions to print layer thicknesses of at least 500 μm, typically used for this application and substantially exceeding the current state-of-the-art. First, rheological and print experiments were conducted with 25 distinct adhesives, including ultraviolet (UV) curable acrylics and epoxies, to determine their printability. An adhesive was considered printable when it detached from the stencil without forming bubbles, a print defect that significantly diminishes the process stability. This had to be accomplished at two different squeegee speeds (40 and 160 mm/s), confirming the robustness of the adhesive for the print process. In addition, the impact of the aperture orientation, aperture aspect ratio (AR) and separation speed of the substrate from the stencil were evaluated. Here, it was detected that a multivariable criterion was necessary to reliably predict printability. Thus, classification models based on binary logistic regression, a simple supervised machine learning technique, were proposed using the thixotropy index TI (indicator for viscosity recovery ability), steady-state viscosity at 100 s−1, adhesive surface tension and aperture AR as predictors. The derived models achieved a prediction accuracy ≥88.2%, demonstrating adequate generalisation. Moreover, it was identified that increasing TI is the most effective approach to achieve printability. Finally, the driving physical mechanisms influencing the obtained print results were assessed, and it was shown that a TI value of about 50 Pa s/s is required to reach the minimum layer thickness.

Key Technology of 240°C High-Temperature Drilling Fluid

Hot dry rock (HDR) is a renewable green and clean energy source from the depths of the earth. It has the characteristics of high efficiency, environmental protection, safety, and stability, and is not restricted by seasons and climates. Difficulties in exploration and development include deep burial, formation fragmentation, abnormal pressure, high well temperature gradient, and high hole bottom temperature (usually >200°C), key technical issues such as sticking. This paper analyzes the difficulties of high-temperature resistant drilling fluid in dry hot rock: temperature resistance of treatment agents and systems, foaming, leakage, wellbore instability, and other problems. The optimization and experiment of treatment agents such as loss reducers, high-temperature protective agents, etc., and research on drilling fluid technology resistant to high temperature of 240°C in hot dry rock drilling has been carried out, through the optimization experiment of pulping materials and high temperature treatment agent. The main formula is: 3%-4% Sodium bentonite + 2%-3% HPS + 3%-4% SPNH + 2%-4% GJA + 3%-4% JSJ-1 + 0.5%-1.0% GGDP + 1% GBHJ. The drilling fluid formula has good rheology after hot rolling at 240°C, API filtrate loss<5ml, the viscosity recovery rate is over 90%. It provides effective technical support guarantee for promoting the exploration and development of hot dry rock resources in China.

Cellulose Nanocrystals As a Key in Wearable Sensors

In recent years, the development of cellulose-based inks for 3D printing has received significant interest due to numerous cellulose and its derivatives properties [1], [2]. Carboxymethyl cellulose (CMC) is an anionic water-soluble cellulose derivative widely used as superabsorbent hydrogels [3]. Another cellulose derivative is cellulose nanocrystal (CNC), a rod-like nanoparticle that can be applied for the mechanical strengthening of hydrogels and also presents potential use in several applications in the biomedical field [2], [4]. Based on this, we have proposed to investigate if CMC and CNC mixtures result in cellulose-based nanocomposite gels suitable for extrusion printing of wearable sensors. Interactions between CNC and CMC resulted in physical gels, where rheological properties and extrusion printing parameters' effects were studied. A Modular Compact Rheometer (Anton Paar MCR-102, Austria) with a plate-plate geometry (50 mm diameter and 1 mm gap) at 25 °C was used to perform rheological measurements. Extrusion printing was performed on the customized 3DCloner Lab printer using a 22G nozzle tip of 25 mm in length and a diameter of 0.70 mm (Injex, Brazil). Gels presented shear-thinning, solid-like viscoelastic behavior, viscosity recovery, and continuous filaments obtained during printing. Moreover, the alignment of rod-like CNC during the printing process can be a key to improving properties. Tests with different print and extrusion speeds evidenced the influence of the wearable sensor's geometry and mechanical properties. Moreover, the low cytotoxicity of CMC/CNC crosslinked hydrogels was confirmed through an MTT assay of fibroblasts. Further testing is being conducted to evaluate the self-healing and conductive properties of the sensors by external stimuli. Moreover, low cytotoxicity to CMC/CNC crosslinked hydrogels was confirmed through an MTT assay of fibroblasts. External stimuli are being applied to evaluate the self-healing and conductive of the sensor printed.

Rheology in Product Development: An Insight into 3D Printing of Hydrogels and Aerogels.

Rheological characterisation plays a crucial role in developing and optimising advanced materials in the form of hydrogels and aerogels, especially if 3D printing technologies are involved. Applications ranging from tissue engineering to environmental remediation require the fine-tuning of such properties. Nonetheless, their complex rheological behaviour presents unique challenges in additive manufacturing. This review outlines the vital rheological parameters that influence the printability of hydrogel and aerogel inks, emphasising the importance of viscosity, yield stress, and viscoelasticity. Furthermore, the article discusses the latest developments in rheological modifiers and printing techniques that enable precise control over material deposition and resolution in 3D printing. By understanding and manipulating the rheological properties of these materials, researchers can explore new possibilities for applications such as biomedicine or nanotechnology. An optimal 3D printing ink requires strong shear-thinning behaviour for smooth extrusion, forming continuous filaments. Favourable thixotropic properties aid viscosity recovery post-printing, and adequate yield stress and G' are crucial for structural integrity, preventing deformation or collapse in printed objects, and ensuring high-fidelity preservation of shapes. This insight into rheology provides tools for the future of material design and manufacturing in the rapidly evolving field of 3D printing of hydrogels and aerogels.

Geopolymer mortars for use in construction 3D printing: Effect of LSS, graphene oxide and nanoclay at different environmental conditions

The environmental impact of concrete 3D printing (C3DP) has become a concern due to its large cement consumption and over-exploitation of natural resources. This study investigates the viability of using geopolymer mixtures in C3DP prepared with fly ash (FA)/ground granulated blast furnace slag (GGBS) and underutilised aggregate as substitutes for ordinary Portland cement (OPC) and natural aggregate, respectively. This paper focuses on the rheological, mechanical, and shrinkage properties of FA/GGBS-based geopolymer mortar with lead smelter slag (LSS) as natural sand (NS) substitute and the impact of adding nanoclay (NC) and graphene oxide (GO), as thixotropy agents, on the yield stress development and viscosity recovery properties of the mixtures. The effect of various outdoor environmental conditions of 24 °C -50 %RH, 35 °C -90 %RH and 35 °C -50 %RH on pore water evaporation and 28-day drying shrinkage of 3D printable geopolymer mortar was studied, considering the effect of NS, LSS, NC and GO in free-formed and control conditions. LSS GO-modified mortars exhibited superior viscosity recovery capacity and yield stress evolution compared to their NC-modified counterparts. Moreover, using LSS instead of NS resulted in increased 28-day compressive strength under various environmental conditions, and LSS mortars exhibited lower drying shrinkage in both conventional casting and free-formed conditions. The findings of this paper will serve as a benchmark for further studies on the effect of different curing techniques (internal or external) on the hardened state dimensional stability of 3D printed products using alkali-activated binder systems to improve the structural integrity by controlling the water evaporation and drying shrinkage development.

Tribology and Rheology of Polypropylene Grease with MoS2 and ZDDP Additives at Low Temperatures

Polypropylene (PP) grease is a type of lubricating grease with excellent low-temperature performance. The wear and friction performance of steel/steel couples lubricated with PP grease containing molybdenum disulfide (MoS2), zinc dialkyldithophosphate (ZDDP) and MoS2/ZDDP as additives at low temperatures was investigated using an Optimol SRV reciprocating tester. Compared with MoS2 or ZDDP as single additives, the combination of MoS2 and ZDDP resulted in outstanding tribological properties, especially for higher-load, longer-duration and low-temperature working conditions. The analysis of the wear surface indicated that MoS2 not only adhered to the steel surfaces to form a solid film, but also combined with ZDDP to form a tribofilm. The active components of the additives reached the metal surfaces effectively, indicating that the polymer system did not interfere with the function of the additives. The rheological experiment results also showed that PP grease with additives can maintain stable viscoelasticity, viscosity recovery rates and ductility at low temperatures.

Use Of Mining Tailings in The Manufacture of Ecological Bricks to Encourage the Construction of Sustainable Housing

This work aimed to manufacture ecological bricks using mining tailings, by-products of mining activity, to contribute to sustainable housing development. The Peruvian technical standards E.060 and E.070 are used as a reference framework to achieve this. The study focuses on various aspects, such as mineralogical analysis, particle size distribution, plasticization, workability, and rheology. The research methodology adopted is deductive, with an applied and quantitative approach. A retrolective data collection instrument and descriptive, explanatory, correlational, and descriptive level approaches are used. The results obtained from this research reveal significant findings. It was observed that including 20% of an alkaline binder based on calcined clay improves the development of bricks in areas with severe climatic conditions. In addition, incorporating lime fibers reduces thermal conductivity and increases bricks' compressive and bending strength. Blocks containing 30% clay cork reinforce the bricks' bulk density, thermal conductivity, and strength. On the other hand, it was verified that tailings with lead-zinc sulfide, reduced by 47%, comply with the carbonization and contraction coefficient. Shale, fly ash, and cement tailings achieved a compressive strength of 26 MPa and a water absorption rate of 14.32%. The addition of steel filings by 3% improves compressive strength. Likewise, incorporating plastic waste increases the compressive strength to reach 37.5 MPa. As for geopolymers, it was observed that viscosity recovery is in a range between 65% and 82%. Finally, recycled aggregates, with a maximum nominal size of 3/8" and 1/4", meet the standard requirements, providing a compressive strength of up to 8 MPa. Finally, this study demonstrates the potential of using mining tailings and other recycled materials to manufacture ecological bricks for sustainable housing development in mining communities, offering viable solutions from an environmental and construction point of view.

Improvement of 3D white chocolate printing molding effect with oleogels

This study used oleogels to resolve unsolidified white chocolate in 3D printing. Because white chocolate cannot be shaped during 3D printing, the oleogel system is used to solve this problem. The printing parameters and accuracy in a 3D printing system were investigated by using different oleogels added to white chocolate as a material to enhance chocolate extrusion solidification, monoglycerides (MAG), sucrose fatty acid ester (SE) and hydroxypropyl methylcellulose (HPMC), and their effects on rheological characterization, bridging experiments, and optimal print parameters (material formulation, nozzle height, layer height and print speed) were compared. In the rheological analysis, the viscosity recovery was more than 80% for the HPMC group and less than 80% for the MAG and SE groups. In the bridging experiment, when MAG and SE were added at more than 2%, the white chocolate could be effectively extruded and solidified, and the bridging distance could be stretched to 10 mm. The suitable printing parameters are a nozzle height of 3 mm, a layer height of 3 mm, and a printing speed of 10 mm/s. This study provides a future solution to solve the problem of extruded unsolidified chocolate.

Study on Preparation and Rheological Properties of 3D Printed Pre-Foaming Concrete

The high fluidity and low yield stress of fresh foam concrete affect the shape stability and buildability of foam concrete in the printing process, which is quite a challenge to its application in digital construction. Therefore, this article proposes the preparation and characteristics of 3D printed pre-foaming concrete (3DFC). The rheological properties proved that the addition of 0.1 wt.% Hydroxypropyl methyl cellulose (HPMC) to 3DFCs weakens the fluidity but increases the static yield stress and apparent viscosity, thus enhancing the buildability. More importantly, the influences of surfactant on the rheological property, compressive strength, pore structure and thermal conductivity of 3DFCs were evaluated. Analysis results show that the static yield stress of 3DFCs decreases from 1735 to 687 Pa with surfactant dosage from 0 to 2 wt.%. Moreover, the addition of surfactant significantly reduced the apparent viscosity of 3DFCs (especially at low shear rates), but its viscosity recovery rate was basically unchanged, which is good for buildability. Thanks to the increase of porosity, the volume density of 3DFCs decreased from 2211 to 1159 kg/m3, but the compressive strength of 3DFCs also decreased slightly. The thermal conductivity of 3DFCs shows good thermal insulation performance in the range of 0.2254–0.2879 W/m·K, which is also due to the increase in porosity of 3DFCs. Finally, in order to verify the practical application value of 3DFCs, an industrial printing product with more than 30 layers during the field application is displayed.

Nanomaterials as Promising Additives for High-Performance 3D-Printed Concrete: A Critical Review.

Three-dimensional (3D) printed concrete (3DPC), as one of the subset of digital fabrication, has provided a revolution in the construction industry. Accordingly, scientists, experts, and researchers in both academic and industry communities are trying to improve the performance of 3DPC. The mix design of all kinds of concrete has always been the most crucial property to reach the best efficiency. Recently, many studies have been performed to incorporate nano- and micro-scale additives to ameliorate the properties of 3DPC. The current study aims to present the main design properties of 3DPC and completely cover both fresh and hardened state characteristics of 3DPC containing different nano- and micro-additives. Our observations illustrate that nanomaterials can be mainly utilized as a thickener to ameliorate the thixotropic behavior and the structural build-up of 3DPC, resulting in higher yield stress and better viscosity recovery. Furthermore, each nanomaterial, through its unique impact, can provide lower porosity and permeability as well as better mechanical strengths for 3DPC. Although much research investigate the fresh properties of 3DPC containing nano and micro additives, future studies are needed to provide better insight into the impact of these kinds of additives on the hardened characteristics of 3DPC. In addition, researchers may devote more research to address the effects of the additives discussed herein on the performance of other kinds of 3DPC such as lightweight, self-compacting, etc. It should be noted that the effect mechanism of nanomaterials on the inter-layer bond strength of 3DPC is another crucial issue that should be investigated in future studies. Furthermore, nano-scale fillers from source of waste and biomass can be attractive additives for future research to achieve high performance of sustainable 3D-printed concrete.

Impact of physico‐chemical properties of nanocellulose on rheology of aqueous suspensions and its utility in multiple fields: A review

AbstractNanocellulose (NC), due to its sustainable nature, high aspect ratio, superior mechanical strength, and availability of functionalizable OH groups, has been widely utilized as reinforcement in numerous fluids/plastics. The physico‐chemical properties of NC, like surface characteristics, dimensions/aspect ratio and their concentration, significantly impact the interparticle interactions, such as the extent of hydrogen bonding, van derWaalforces, hydrophobicity, electrostatic attraction/repulsion, and cellulose entanglement, and have been found to play a critical role in regulating the overall rheological characteristics of fluids. The functionalized NC aqueous suspension exhibited unique shear thinning properties, thixotropic behavior, and quick steady‐state viscosity recovery and viscoelastic properties. However, upon adding functionalized NC to other fluids, a different impact was noticed. For instance, it improved the viscosity, G′ and mechanical stability of bio‐ink; the setting time and mechanical strength of cementitious fluids; increased the filtration performance and provided a unique thermo‐thickening impact in case of water‐based drilling‐fluid; enhanced viscosity with time and heat in case of oil recovery, and so forth. Keeping in view the notable dependence of the rheology of fluids on NC additives, in the present review article, the impact of various physico‐chemical properties of NC additives on the rheological behavior of NC aqueous suspension and its utility as a rheology modifier in multiple advanced fields has been explored. This review article, compared to previous studies, warrants an update on the impact of recent NC surface functionalization/blending techniques employed and NC aspect ratio on specific properties of multiple advanced fluids.

Molecular simulation of the rheological properties and shear thinning principles of supramolecular drilling fluids at different burial depths.

In order to investigate the rheological properties and shear thinning principles of supramolecular drilling fluids, the salt-responsive supramolecular ionomer polymers with different components were designed and the change in shear viscosity of supramolecular polymer drilling fluid system with shear rate was studied using the molecular dynamics simulation method. The result indicated that the ionic supramolecular polymer drilling fluid system exhibits better self-assembly performance than the nonionic acrylamide drilling fluid system. Moreover, the drilling fluid system exhibits the best rheological properties and self-assembly performance when the feeding ratios of the three monomers in the two polymers are m : n : o = 5 : 90 : 5 and m : n : o = 30 : 40 : 30, respectively. The shear viscosity recovery rate of the #3 ionic supramolecular polymer drilling fluid system at different burial depths (1-5 km) is >87%, where the shear viscosity is mainly determined at ambient pressure. The shear thinning phenomenon of the supramolecular polymer drilling fluid system occurs because of the combined effect of the polymer molecular orientation and entanglement structure. When the shear rate is above a critical value, the polymer molecules are oriented along the flow field direction, decreasing the shear viscosity. However, when the shear rate is very high, the entanglement structure of the molecules is opened and the mesh structure of the fluids is disrupted, decreasing the shear viscosity of the drilling fluid.