Rheological Properties Research Articles

Ecofriendly hybrid natural fiber reinforced polypropylene composites from biowastes

The used ground coffee waste (GCW) and tea leaf waste (TLW), the large wastes from the beverage process, were selected as natural reinforcement and natural pigment in the polypropylene (PP) matrix. In this work, the maleic anhydride polypropylene (MAPP) was added to the composites to develop the compatibility between fillers, fibers, and polymer matrix. The TLW/PP composites, GCW/PP composites, and GCW/TLW/PP hybrid composites were prepared in the ratio of TLW and GCW ranging from 0 to 30 wt% with the addition of MAPP at 5 wt% of fillers. The presence of GCW and TLW in the PP matrix decreased tensile properties and impact resistance but increased flexural modulus and hardness of PP at high concentrations of GCW and TLW. The increase in GCW and TLW concentration slightly reduced melting temperature but it enhanced the tensile and flexural modulus. Furthermore, it enhanced the hardness, thermal and rheological properties of the composites. The TLW/PP composites had better mechanical properties, and rheological properties than GCW/PP composites but thermal properties were quite similar. The mechanical properties of GCW/TLW/PP hybrid composites were better than those of GCW/PP composites but lower than those of TLW/PP composites. The rheological and thermal behaviour of hybrid composites were like that of TLW/PP composites. Incorporating MAPP improves the mechanical and rheological behavior of PP composites by enhancing the interaction among PP, GCW, and TLW. However, this addition does not significantly enhance the composites’ thermal properties. The optimum composite was hybrid composites of GCW/TLW/PP consisting of GCW of 10 wt%, TLW of 20 wt%, and MAPP of 1.5 wt% which presented good mechanical, thermal, and rheological properties. The mechanical properties of this hybrid composites were as follows: a tensile strength of 26.35 MPa, elongation at break of 10.91%, tensile modulus of 636.69 MPa, flexural strength of 45.57 MPa, flexural modulus of 3632.86 MPa, impact resistance of 12.72 kJ/m2, and a Shore D hardness of 76.15. The overall results showed that GCW and TLW can be used as reinforcement material and natural pigment in the polymer matrix.

Understanding the time-dependent rheological behavior of seawater mixed cement paste with fly ash

Due to the relative scarcity of freshwater resources in coastal regions, the use of seawater in concrete construction has great potential due to its benefits in cost and resource. To further advance the application of seawater concrete, a deeper understanding of its rheological properties is essential. This study investigates the effects of fly ash on the time-dependent rheological behavior of seawater cementitious paste, such as yield stress, plastic viscosity, and structural build-up rate. The underlying mechanisms are analyzed using the theories of water film thickness (WFT), ion concentration, and hydration heat. The research findings confirm that the rheological parameters of seawater paste are generally higher than those of deionized water paste, regardless of the cementitious compositions. As fly ash content increases, the plastic viscosity of seawater paste increase, while the fluidity and dynamic yield stress decreases. Further analysis reveals that the decrease in the yield stress with fly ash content is well related to the increase in the WFT, but it cannot sufficiently explain the change of yield stress over time. Instead, the amount of hydration products in seawater paste shows a linear increasing relationship with the dynamic yield stress at 65 min. By contrast, the plastic viscosity can be related to the ion concentration in the interstitial solution, wherein an increase in the concentration of Ca2+ corresponds to an increase in the plastic viscosity. Moreover, the rheological parameters increase over time, with the growth rates between 5 and 35 minutes being higher than those between 35 and 65 minutes, possibly due to the rapid early hydration of the binder materials. This study offers a fundamental theoretical support for the use of seawater in various concrete applications.

Machine-Learning Approach PredictsGel Strength of Drilling Fluid While Drilling

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 35433, “Novel Machine-Learning Approach for Predicting the Gel Strength of the Drilling Fluid While Drilling,” by Ahmed Gowida, SPE, and Salaheldin Elkatatny, SPE, King Fahd University of Petroleum and Minerals. The paper has not been peer reviewed. Copyright 2024 Offshore Technology Conference. _ Accurately estimating gel strength is paramount for optimizing drilling operations and preventing cuttings from settling at the wellbore’s bottom. Traditional methods rely on rotational viscometers, which are time-intensive, equipment-dependent, and lack real-time monitoring capabilities. This study underscores the feasibility of leveraging machine learning (ML) as a practical tool for predicting drilling-fluid gel strength, offering real-time monitoring and precise predictions to enhance drilling efficiency, safety, and automation initiatives. Background The gel strength of drilling fluid is assessed using a viscometer, focusing on the 3-rev/min reading obtained after agitating the fluid at 600 rev/min to disrupt any gel formation. Initially, the measurement is taken when the mud reaches a static state for 10 seconds. Subsequent readings are conducted at 10- and 30-minute intervals. The rationale behind the 30-minute reading lies in its ability to indicate whether the mud forms a substantial gel during prolonged static periods, such as when tripping out a bottomhole assembly. Elevated gel strength may result in increased pump pressure required to restore circulation after extended static conditions. Additionally, a consistent upward trend in the 30-minute gel strength suggests the accumulation of ultrafine solids. Consequently, appropriate measures such as chemical treatments or dilution with fresh base fluid are necessary to address this issue. The frequency of measuring various fluid properties is tailored to their respective effects on well-control and drilling operations. These frequent evaluations allow for timely adjustments and monitoring of rheological measurements, offering valuable insights into rock sensitivity and the performance of mud activity and stability after exposure to drilled formations. On the other hand, a complete mud test (including all mud rheological properties) is performed twice a day because it consumes considerable time. It has been observed that mud rheological properties exhibit a significant correlation with two fundamental mud properties: mud weight and Marsh funnel (MF) viscosity. To the best of the authors’ knowledge, a dearth of research exists in the literature aimed at predicting the gel strength of drilling fluid using ML techniques. Consequently, this research endeavor introduces a novel ML model designed specifically for forecasting the gel strength of synthetic oil-based mud systems. Such predictive models are poised to enhance drilling performance by optimizing mud functions. Leveraging MF and mud-density measurements, the developed models aim to forecast the rheological properties of drilling fluid, thereby facilitating improved monitoring of mud functionality during drilling operations at the rig site.

Drying of avocado peels using carbonation-ultrasonication as pretreatment: energy consumption, antioxidant capacity and rheological properties

Fruit processing by-products, especially peels are underused and mostly discarded as waste. The aim of this study was to assess the effect of ultrasonication (US) combined with carbonation (CUS) on the convective drying process of avocado peels at different temperatures, adding value to this waste. For this, the avocado peels were treated with dry ice for 15 min and subjected to US (400W/10 min, 30°C) before convective air drying (50-70°C). The energy consumption, antioxidant capacity, water adsorption isotherms, rehydration rate, and dynamic rheology of dried avocado peels pretreated by CUS were compared with a control process (without pretreatment) and only US pretreatment. The combined treatment (CUS70) resulted in a 2.6-fold reduction in drying time and a 2.3-fold decrease in energy consumption, with CO2 preserving bioactive compounds and antioxidant capacity after the drying process. Differences were also observed in the rehydration capacity of the samples (CUS), with an increased water absorption capacity, along with a reduction in the viscoelastic properties of the peels. The results present new perspectives for the application of CUS in the food industry, paving the way for the development of creative, innovative, and simple approaches for the management and recycling of agri-food waste, with the potential to extend this knowledge to new food matrices.

Improvement on gel properties of chicken myofibrillar protein with electron beam irradiation: Based on protein structure, gel quality, water state

This study aimed to investigate the effects of electron beam (E-beam) irradiation at different doses (0–15 kGy) on the solubility, rheological properties, emulsification characteristics, and moisture distribution of chicken myofibrillar proteins (MPs). Irradiation treatment notably increased the solubility, surface hydrophobicity, emulsification properties, and apparent viscosity of MPs, based on conformational changes caused by irradiation-induced oxidative denaturation of proteins. However, high doses of irradiation (15 kGy) induced in excessive cross-linking and aggregation of proteins, reducing the solubility, emulsification properties, and shear stress. Degradation of myosin heavy and light chains in irradiated MPs increased the content of β-turns and random coils. Additionally, the initial relaxation times of T21 and T22 in irradiated protein gels were reduced, and the peak value of P21 was increased, which improved the water-capturing ability of protein gels. Altogether, these results findings suggest that electron beam irradiation can be applied as a potential technique for modifying muscle proteins.

Anti-dispersion, rheological, and mechanical properties of GBFS/FA geopolymer for underwater engineering applications

Anti-dispersion, rheological, and mechanical properties of GBFS/FA geopolymer for underwater engineering applications

Ion-Mediated Cross-Linking of Hyaluronic Acid into Hydrogels without Chemical Modification.

Hyaluronic acid (HA) is a biomedically relevant polymer widely explored as a component of hydrogels. The prevailing approaches for cross-linking HA into hydrogels require chemically modifying the polymer, which can increase processing steps and complicate biocompatibility. Herein, we demonstrate an alternative approach to cross-link HA that eliminates the need for chemical modifications by leveraging the interactions between metal cations and the negatively charged, ionizable functional groups on HA. We demonstrate that HA can be cross-linked with the bivalent metal cations Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), and notably Mg(II). Using Mg(II) as a model, we show that ion-HA hydrogel rheological properties can be tuned by altering the HA molecular weight and concentrations of ions, NaOH, and HA. Mg(II)-HA hydrogels showed the potential for self-healing and stimulus response. Our findings lay the groundwork for developing a new class of HA-based hydrogels for use in biomedical applications and beyond.

Synergistic enhancement of poly(lactide) melt strength via copolymerization and multi-arm branching strategy

The lower melt strength of poly(lactide) (PLA) limits its broader applications. Here, a strategy combining copolymerization with multi-arm branching was propose to enhance the melt strength of PLA. Initially, stereoisomeric cyclic ester monomers (CEM) synthesized via zeolite catalysis were copolymerized into PLA chains. Subsequently, rheological testing revealed that the zero-shear viscosity (η0) of linear PLA increased by 467 % with only 1 mol% of CEM units. Our study further systematically explored the relationship between the side group structure and chirality of the comonomers and the rheological properties of the copolymers. CEMs with long-chain branched structures and opposite chirality had the best enhancement effect. In order to further enhance the melt strength, we successfully achieved alterations in polymer topology by employing trimethylolpropane as an initiator, corresponding three-arm copolymers achieve up to a 67-fold increase in η0 (1.0 kPa∙s to 68.1 kPa∙s). Tensile tests indicated that the mechanical properties of the copolymers were comparable to those of PLA, with a tensile strength of approximately 65 MPa. Additionally, due to the high melt strength, we successfully produced closed-cell PLA-based foam materials with uniform pore sizes. In summary, this study furnishes a feasible method for designing polymer materials possessing the desired melt strength.

Effects of microplastics on the rheological properties of sediment slurries in aquatic environments

Sediment slurries, characterized by their high concentrations of fine-grained cohesive sediment, are prevalent in various aquatic environments, including fluid mud, sediment gravity flows, and dredging slurries. Abundant microplastics have been detected in sediment slurries, which indicates that these slurries function as carriers for the transport of microplastics. However, there is a dearth of understanding on how sediment slurries transport microplastics. To ascertain the transport mechanisms, elucidating the effects of microplastics on the rheological properties of sediment slurries is a prerequisite because these properties govern the flow dynamics and mobility of such slurries. This study conducts experimental and theoretical investigations to examine, interpret, and quantify the effects of microplastics on the rheological properties of sediment slurries. Microplastics are shown to increase the yield stress and viscosity of sediment slurries via enhancing sediment aggregation. A new descriptor, specifically, the effective volume fraction, is proposed to characterize the effects of microplastics on sediment aggregation. Based on the newly-proposed descriptor, a new analytical model is proposed to predict the yield stress and viscosity of sediment slurries with microplastics. This study lays a foundation for further interpretating the flow dynamics and thus the transport processes of sediment slurries laden with microplastics.

Unveiling the synergistic effect of octenyl succinic anhydride and pulsed electric field on starch nanoparticles

In this study, guinea starch nanoparticles (GSNP) were prepared by nanoprecipitation technique and modified with octenyl succinic anhydride (3 %) and pulsed electric field (1.5, 3.0, and 4.5 kV/cm). The effect of dual modification on the physicochemical, structural, morphological, thermo-pasting, and rheological properties of GSNP was investigated. The dual modification successfully incorporated octenyl groups into GSNP, as confirmed by 1H nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The degree of substitution increased from 0.0254 to 0.0347, with particle size ranging from 241.30 to 292.50 nm and zeta potential of −23.11 to −29.98 mV. TEM micrographs revealed that all SNP samples had self-aggregated granules with a mean size below 120 nm, and XRD confirmed a V-type crystalline structure. The amylose content and water absorption capacity decreased from 34.02 % to 24.63 % and from 2.45 to 1.91 g/g, respectively, while the oil absorption capacity and relative crystallinity increased from 3.42 to 4.01 g/g and from 17.82 % to 34.76 %, with modification. The gelatinization and degradation temperature of modified samples were higher while pasting properties exhibited variation with modification. The rheological properties of modified SNP samples exhibited more pronounced shear thinning, attributed to their weaker gel structure and fluid-like gel network. Overall, results suggested that modified GSNPs have potential for stabilizing Pickering emulsion and delivery of carrier materials for active functional substances.

Impact of annealing and incorporation of vegetable oils on physicochemical and rheological properties of wheat starch

Impact of annealing and incorporation of vegetable oils on physicochemical and rheological properties of wheat starch

An Experimental Study on the Rheological Properties of Self-Consolidating Mortars, Affected by Superplasticizer, Waste Marble Powder, and a Viscosity-Modifying Agent

An Experimental Study on the Rheological Properties of Self-Consolidating Mortars, Affected by Superplasticizer, Waste Marble Powder, and a Viscosity-Modifying Agent

Polymer electrolytes based on PEO and lithium tetraalkoxyborate salts with ionic liquid properties for lithium-based batteries

The development of lithium-ion batteries (LIBs) with improved safety features is crucial due to the inherent risks associated with liquid electrolytes, such as fires, explosions, and leakage. This study explores the potential of solid polymer electrolytes (SPEs) based on poly(ethylene oxide) (PEO) and lithium tetraalkoxyborate salts (LiTAB) with ionic liquid properties as a safer alternative. Ionic liquids (ILs) are examined for their high ionic conductivity, wide electrochemical window, and excellent thermal stability, despite their high synthesis costs and viscosity challenges. The study proposes the use of a novel LiTAB salt with an oligomeric star-shaped anion structure that reduces mobility, enhancing lithium ion transference numbers. This IL serves as both a lithium salt and an active plasticizer in PEO-based SPEs, offering potential for 3D printing applications. Experimental results demonstrate that these electrolytes exhibit favorable rheological properties, high ionic conductivities, and significant lithium ion transference numbers, addressing the key limitations of conventional PEO-based electrolytes. The findings suggest that incorporating these LiTAB salts in SPEs could significantly enhance the safety and performance of LIBs, particularly for applications in miniaturized consumer electronics and electronic implants.

Evaluation of the Rheological Properties of Asphalt Binder Modified with Polyvinylpyrrolidone Grafted onto Water-Soluble Graphene and Analysis of the Modification Mechanism

Evaluation of the Rheological Properties of Asphalt Binder Modified with Polyvinylpyrrolidone Grafted onto Water-Soluble Graphene and Analysis of the Modification Mechanism

Effect of epoxidation level on rheological properties of epoxidized natural rubber-based magnetorheological elastomer

Epoxidized natural rubbers (ENR)are potential to be an alternative of natural rubber as matrix of magnetorheological elastomers (MREs). These ENR-based MREs offer various advantages such as excellent mechanical properties and damping characteristics that are well-suited for applications in vibration control and noise reduction devices. However, there is a paucity information in regard to the effect of different epoxidation levels on rheological properties of MRE. Therefore, the main aim of this study is to explore the influence of epoxidation level on rheological properties of MRE using commercialized ENR corresponding to ENR 25 and ENR 50. ENR-based MREs were created by blending with carbonyl iron particles (CIPs) and other additives, followed by curing at 150 °C for 30 min. The study involved producing ten MRE samples with various weight percentages of CIP (0,10,30,50 and 70 wt%). The storage modulus of ENR 50 exhibited a significant increment from 0.73 MPa to 1.04 MPa as compared to ENR 25 which caused the storage modulus to increase from 0.77 to 0.88 MPa. This showed that ENR 50-based MRE are stiffer in comparison to ENR 25-based MRE. Initial loss modulus value for ENR 50 (0.098 MPa) was lower than that of ENR 25 (0.112 MPa), consequently less energy is dissipated to surrounding for ENR 50-based MRE compare ENR 25-based MRE. The loss factor that represents damping properties showed that ENR 50 reached higher values (0.120 MPa) compared to ENR 25 (0.106 MPa). The increasing of CIPs content from 0 to 70 wt% contributed to increasing of magnetorheological effect for both ENR-based MRE where ENR 25 produced slightly higher with increment of 1.88 % to 22.6 % than ENR 50-based MRE with increment of 2.47 % to 18.18 % due to rise of magnetic forces generated from interaction of magnetic moments in magnetic domains of each CIPs. The results and analysis indicate that different levels of epoxidation in ENR have a marginal impact on the rheological properties of ENR-based MREs.

Influence of Grinding Aids on the Grinding Performance and Rheological Properties of Cementitious Systems

The cement industry is of great importance in terms of raw materials consumed, energy consumed, and greenhouse gases emitted. Grinding aids (GA) are used to reduce energy consumption and costs, as well as to reduce the amount of CO2 released into the environment. In this study, the effect of GA-polycarboxylate ether-based water-reducing admixture (PCE) compatibility on some fresh, rheological and hardened state properties of cementitious systems was investigated. In order to investigate the rheological properties and thixotropic behavior of the mixtures, a total of 51 cement paste mixtures were prepared, containing 4 different types (molasses, MEG, DEA and ethanol) and ratios (0.025, 0.05, 0.75 and 0.1) of GAs and 2 different ratios (0.08% and 0.16%) of PCE in addition to the control mixture. In addition, the effect of the used GAs on the grinding efficiency and compressive strength value was investigated. Additionally, the predictability of the type of GA, dosage and cure time using the Taguchi method was investigated. It was determined that the highest grinding performance was obtained in mixtures containing MEG. It was determined that in cement paste mixtures containing GAs, the dynamic yield stress and viscosity values generally decrease with the increase in PCE usage rate up to a certain value, and these values may increase if the PCE usage increases further. It was determined that such behavior is not present in cement paste mixtures containing GAs and that the structural build-up value of the mixtures generally increases with the increase in the PCE admixture usage rate. It was determined that the use of GAs had a positive effect on 28-day compressive strength.

On the printability of high-density polyethylene (HDPE) reinforced with long glass and short carbon fibres

Purpose This research is about the possibilities of using high-density polyethylene (HDPE)-based composites consisting of long glass and short carbon fibres because HDPE is one of the more preferred thermoplastics day by day due to its sustainability, cost-effectiveness and availability in the relevant markets. HDPE has become an increasingly preferred material in the marine industry in recent years due to its high resistance to marine environmental conditions (high resistance to UV, surface-fouling marine organisms and corrosive effects of salty and low-pH water). In the highly competitive boat building industry, additive manufacturing offers new opportunities such as rapid prototyping and design freedom. This study aims to investigate the possibilities of using a material suitable for the marine environment and an additive manufacturing (AM) method offering new possibilities, especially for small craft with complex forms. Design/methodology/approach A total of six new HDPE-based composites consisting of long glass and short carbon fibres at 10, 15 and 20% by weight have been proposed for the first time in this study for the use in boat building industry, proposing the application of these new composite materials with AM method, which the industry is not yet fully adopted, is also an innovative aspect of the study. The performances of the materials in AM’s material extrusion (MEX) method were evaluated using the results obtained from mechanical (tensile, compression, shear and impact) and thermal (melt flow index [MFI], thermogravimetric analysis [TGA] and thermomechanical analysis [TMA]) tests. In addition, the structure of the composites was examined with scanning electron microscopy and micro computed tomography visually, and the rheological properties of the composites were also determined by the related tests. As an industrial case study, a ship propeller was manufactured from the composites produced with CF15, which was thought to give the best performance in marine use, and this propeller was tested under water flow. Findings It is evaluated that the composites proposed in this study can be used in marine industry in line with the analyses and test results. The performance of the propeller produced as a case application also confirms this view. The printability of HDPE-based composites, reinforced by both glass and carbon fibre, is much better than that of pure HDPE, and the composites are suitable for use AM’s MEX method in boat building industry. As the fibre contents in the proposed composites increase, the strength values increase and the impact resistance and hardness decrease. The CF15 composite, which meets each of those mechanical and physical values at an average level, is a recommended option for marine applications. Originality/value This study has two basic originalities: (1) On the basis of HDPE, which is widely used in the marine industry, to produce composites that will overcome the deficiencies of this material in practice and to present them to relevant industry by improving their properties; (2) at the same time, to discuss for the first time the use of new HDPE-based materials in AM, whose printability has also been improved through composite, to help dissemination of AM technologies in marine industry in general and in the boat building industry in particular.

3D‐printing continuous plant fiber/polylactic acid composites with lightweight and high strength

AbstractContinuous plant yarn‐reinforced polylactic acid (PLA) composites were produced through in situ 3D printing, focusing on how plant fiber attributes influence the crystallization, mechanical, and rheological properties of the printed composites. The aim of this study was to assess the viability of plant fibers as substitutes for synthetic ones in engineering additive manufacturing. Plant fibers promoted the crystallization of PLA due to their shear induction and nucleation agent induction effects. The inherent triangular void defect during printing decreased with increasing plant fiber‐volume fraction. Rheological analysis revealed a transition to more elastic behavior post‐fiber addition, indicating solid‐like properties. The tensile strength of flax fiber‐yarn/PLA composite (volume fraction of 50.79%) was 342.37% higher than that of pure PLA, with a 22.2% lower density than pure PLA. Flax fiber demonstrated a superior reinforcement effect than carbon fiber in compressive strength for 3D printed honeycomb sheets with lower energy consumption and footprint. Optimizing fiber characteristics holds promise for high‐performance 3D‐printed natural fiber composites, particularly in vehicle applications.Highlights Plant fiber/polylactic acid (PLA) composites were in situ printed with a volume fraction of 50.79%. Plant fibers promoted the crystallization of PLA during the printing process. The tensile strength of flax fiber/PLA increased by 342.3% with a 22.2% lower density than PLA. Flax fiber showed a better reinforcement than carbon fiber in a compressive test of printed honeycomb.

Grape pomace high-methoxyl pectin: A new prebiotic stabilizer for low-fat synbiotic yogurt gels - Optimization and characterization.

High-methoxyl pectin (HMP, 72.5 % esterification degree and galacturonic acid content of 67.9 %) was extracted from grape pomace using a sequential ultrasound-microwave extraction. The extracted HMP was used to develop low-fat synbiotic set yogurts containing probiotic cells. Higher grape pomace pectin (GPP) concentrations (0.5-2 %) increased the probiotic bacterial population of Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum BB-12. Higher cell viability was observed for L. acidophilus LA-5 compared to B. bifidum BB-12. A response surface optimization showed that the presence of 8.08 Log CFU mL-1L. acidophilus LA-5 and 1.88 % HMP experimentally resulted in the best probiotic viability (10.83 ± 0.11 Log CFU mL-1), overall acceptability (8.03 ± 0.06), and pH (4.25 ± 0.05) values. Compared to pectin-free probiotic yogurts, the optimal yogurt gels presented higher probiotic survivability, lower syneresis, and superior storage-dependent sensory attributes during 21 days of storage. However, a 14-day storage period was generally deemed suitable. The GPP-containing yogurt compared to the pectin-free sample exhibited higher colloidal stability with a larger particle size (433.8 nm vs. 272.5 nm) and lower zeta potential (-20.4 mV vs. -10.6 mV). Field emission-scanning electron (FE-SEM) and fluorescent (FLM) microscopy images confirmed a denser microstructure for GPP-enriched yogurts. The chemical interactions in the yogurt were not affected by enriching with GPP as investigated by FTIR, whereas the steady and dynamic rheological properties were significantly improved. GPP-enriched yogurt had a firmer gel structure with a larger linear region and lower G' compared to the control, indicating a semi-solid state. The GPP as a multi-functional prebiotic ingredient would be promising in designing healthier food products.

Fabrication of Highly Sensitive Porous Polydimethylsiloxane Pressure Sensor Through Control of Rheological Properties

Fabrication of Highly Sensitive Porous Polydimethylsiloxane Pressure Sensor Through Control of Rheological Properties