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Nanocomposite grease was created to reduce wear and friction on surfaces and enhance thermal conductivity. The tribological and rheological properties of nano grease were studied. Calcium grease with varied doses of hybrid TiO2/CNTs/GNs (0.5, 1, 2, 3 wt.%) was prepared. Transmission electron microscope (TEM) was applied to look at the microstructure of nano grease. Tribological and rheological properties of the nano grease were examined by using a four-ball tester. Wear scar diameter (WSD) was reduced by 30% at the optimal TiO2/CNTs/GNs concentration of 2% before beginning to rise. As TiO2/CNTs/GNs are applied in concentrations ranging from 0 to 2 wt.%, the friction coefficient of nano additive containing calcium grease steadily declines. At 2% concentration, the reduction in coefficient of friction was 45% about base grease. The friction coefficient was increased after that to 3 wt.%. Shear rate was reduced when the dose of TiO2/CNTs/GNs was increased. As the concentration of nanomaterials and shear rate increased, so did the viscosity of nano grease. Shear stress and apparent viscosity of the calcium grease containing 3% by weight of TiO2/CNTs/GNs are 43% higher than pure calcium grease, although they are still much lower than pure grease. The inclusion of the nanomaterial causes a roughly 19.5% increase in the dropping point of base grease. The thermal conductivity of nano grease is significantly improved by nano additives, increasing by around 130%, and the additives have a dramatic linear growth on the thermal conductivity of nano grease. [ABSTRACT FROM AUTHOR]

This research investigates the biocompatibility, mechanical strength, and tribological properties of a hybrid composite material composed of high-density polyethylene (HDPE), hydroxyapatite (HAp), and titanium dioxide nanoparticles (Ti O 2 ). The study explores the microstructural characteristics of the composite material using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Samples of HDPE-30%HAp with varying concentrations of Ti O 2 (5, 10, 15, and 20%) were prepared and extruded using a twin-screw machine. The hybrid composite materials underwent mechanical tests (tensile, flexural, and hardness), tribological tests (friction and wear rate), and antibacterial tests (resistance to Escherichia coli and Staphylococcus aureus bacteria). The results indicate that the optimal hybrid composite sample was HDPE-30%HAP-10% Ti O 2 , which demonstrated excellent mechanical properties (maximum tensile strength of 25.93 MPa and young modulus of 480 MPa) and a low coefficient of friction (COF∼ 0.07) while achieving high wear resistance (wear rate in the order of 1 0 − 4 m m 3 N − 1 m − 1 ). The study shows that the improvement in mechanical properties results in a corresponding improvement in tribological properties. The antibacterial tests revealed that the hybrid composite material exhibited resistance to E. coli and S. aureus bacteria. The findings of this study suggest that the HDPE-30%HAP-10% Ti O 2 composite is a promising material for use in biomedical applications due to its excellent biocompatibility and desirable mechanical and tribological properties. The study demonstrates the potential of reinforced hybrid composite materials in overcoming the disadvantages of monolithic and hybrid micro-composites and highlights the importance of investigating the microstructural, tribological, and mechanical strength characteristics of composite materials for biomedical applications. [ABSTRACT FROM AUTHOR]

The tribological and rheological properties of hybridized nanocomposite of graphene nanosheets (GNs)/titanium dioxide (TiO2) nanoparticles (NPs) as grease additives were investigated under different concentrations (0.5, 1, 2, and 3 wt.%), different loads, and different temperature. Friction reduction and antiwear of grease having hybridized nanocomposite were measured by using a pin-on-disk tester. The rheological properties and the thermal conductivity of the modified grease were evaluated using a Brookfield rheometer and KD2 thermal analyzer. The morphology and composition of nano additives and nano grease were analyzed by HRTEM and XRD. The results show that the hybridized nano grease has better friction-reduction and anti-wear which are enhanced by about 46.7 and 43.9%, respectively, if compared to the base grease. The rheological behavior of the hybrid nano grease is generally enhanced with an increase in the concentration. On the other hand, thermal conductivity is directly proportional to an increase in the concentration of hybrid nanoparticles. [ABSTRACT FROM AUTHOR]

The current study aims to explore the tensile fracture mechanism and thermo-mechanical efficiency of polyamide-6 (PA6) reinforced with titanium dioxide (TiO2) and multiwalled carbon nanotubes (MWCNTs). The uniform dispersion of the MWCNTs and appreciable interfacing between PA6, TiO2, and MWCNTs were revealed in the fractography figures. The crystallization temperature and degree of crystallinity have been enhanced by the addition of nanoparticles to the PA6 matrix. Young's modulus, tensile strength, and Charpy impact strength improved proportionally concerning reinforcement content. The essential work of fracture (EWF) method was applied to evaluate the toughening and fracture behavior of PA6 hybrid systems. Considerable improvement (+60.6%) in the EWF of PA6–TiO2–MWCNT nanocomposites was observed at 4 wt.% CNT and 2 wt.% TiO2. Limiting oxygen index (LOI) findings demonstrate that a polymer with a combination containing titanium dioxide and multiwalled carbon nanotubes has a highly substantial retardant influence. As a result, the TiO2–CNT combination acts as a synergist filler, offering versatile PA6 composite products. [ABSTRACT FROM AUTHOR]

Abstract The tribological and rheological properties of hybridized nanocomposite of graphene nanosheets (GNs)/titanium dioxide (TiO2) nanoparticles (NPs) as grease additives were investigated under different concentrations (0.5, 1, 2, and 3 wt.%), different loads, and different temperature. Friction reduction and anti-wear of grease having hybridized nanocomposite were measured by using a pin-on-disk tester. The rheological properties and the thermal conductivity of the modified grease were evaluated using a Brookfield rheometer and KD2 thermal analyzer. The morphology and composition of nano additives and nano grease were analyzed by HRTEM and XRD. The results show that the hybridized nano grease has better friction-reduction and anti-wear which are enhanced by about 46.7 and 43.9%, respectively, if compared to the base grease. The rheological behavior of the hybrid nano grease is generally enhanced with an increase in the concentration. On the other hand, thermal conductivity is directly proportional to an increase in the concentration of hybrid nanoparticles. [ABSTRACT FROM AUTHOR]

Oils and grease have beneficial effects on moving parts such as connecting rod, gears, shafts, and engine to reduce wear and friction. The properties of lubricants such as tribological and rheological properties are an important role in oils and grease characterization. Nano additives on lubricant oils play an important role in anti-wear; reduce the coefficient of friction and enhance the rheological properties. The Tribological and rheological behavior of base oil 15W50 which have different concentrations of multi-wall Carbon Nanotubes (MWCNTs) (0.5, 1, 1.5, and 2 wt%), and constant amount of graphene nanosheets (GNSs) (0.5 wt%) were investigated. This research is the first one in studying the effect of hybrid nano additives of (MWCNTs) and (GNs) on the tribological and rheological properties of lubricant oils. Tribological characterization was carried out on four ball testing model under different loads (200, 400, 600, and 800 N). The kinematic viscosity, flash point, pour point, and thermal conductivity of nanofluid added 15W50 lubricant are estimated and compared with base oil. The results showed that nano additives improve the wear scar and coefficient of friction by 78% and 48%, respectively. The flash point, thermal conductivity, kinematic viscosity, and pour point, were improved by 15%, 77%, 76.8%, and 20%, respectively compared with the base oil. The hybrid addition of CNTs/GNs nanoparticles enhanced the properties of 15W50 engine oil. [ABSTRACT FROM AUTHOR]

In recent years, since the discovery of Nano-additives especially carbon nanotubes (CNTs) and graphene, many interesting articles on composites with CNTs have been studied. CNTs have attracted considerable interest in all fields of science because of its unique characteristics. In this study, aluminum (Al) matrix reinforcement by the different volume fraction of Al2O3 and CNTs composites have been manufactured by using a powder metallurgy technique. The effects of tribological behaviors, density, hardness, and compression strength behavior of aluminum matrix Nano-composite were investigated before and after Hot Isostatic pressing (HIP). Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM) were employed to check the CNTs and hybrid composites. Results show that the density of nanocomposites decreased by 38% but after HIP, the density decreased by 45%. In addition, the hardness enhanced by 40% but, after HIP the hardness became 67%. On the other side, the compressive strength enhanced by 38% and 60% before and after HIP respectively. The coefficient of friction of nanocomposites are improved by 39%, 48% with HIP and without HIP while the wear rates improved by the addition of Al2O3 and CNTs at all volume fraction by 20%, but after HIP the enhancement became 45% at all volume concentration. [ABSTRACT FROM AUTHOR]

The addition of graphene nanosheets (GNSs) in lubricating grease could significantly reduce the interfacial friction and improve the load-bearing capacity of the parts. Therefore, it has been considered as having great potential as lubricant additives. In this study, we synthesized GNSs that are prepared by a modified Hummer method, and investigated the effect of GNS with different concentration (0.5%, 1%, 2%, 3%, and 4 wt%) on the tribological properties of the calcium grease. The friction and wear experiments were performed using a four-ball tribometer. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to examine the GNS and the friction mechanisms. Results indicate that the friction reduction ability and anti-wear property of the base grease can be improved with the addition of GNS. It was also found that the friction reduction decreases by 61%, and the wear scar diameter (WSD) decreases by 45%, and the extreme-pressure (EP) properties increased 60% at 3 wt% GNS. It is clear that the GNS in grease easily forms protective deposited films to prevent the rubbing surfaces from coming into direct contact, thereby improving the entire tribological behavior of the grease. [ABSTRACT FROM PUBLISHER]

The development of highly efficient photocatalysis has been prepared by two different methods for the photodegradation of Cr(VI) from an aqueous solution under visible light. The electrospun polyethersulfone (PES)/iron oxide (Fe3O4) and multi-wall carbon nanotubes (MWCNTs) composite nanofibers have been prepared using the electrospinning technique. The prepared materials were characterized by SEM and XRD analysis. The result reveals the successful fabrication of the composite nanofiber with uniformly and smooth nanofibers. The effect of numerous parameters were explored to investigate the effects of pH value, contact time, concentration of Cr(VI), and reusability. The MWCNTs-Fe3O4@PES composite nanofibers exhibited excellent photodegradation of Cr(VI) at pH 2 in 80 min. The photocatalysis materials are highly stable without significant reduction of the photocatalytic efficiency of Cr(VI) after five cycles. Therefore, due to its easy separation and reuse without loss of photocatalytic efficiency, the photocatalysis membrane has tremendous potential for the removal of heavy metals from aqueous solutions. [ABSTRACT FROM AUTHOR]

This research investigates the biocompatibility, mechanical strength, and tribological properties of a hybrid composite material composed of high-density polyethylene (HDPE), hydroxyapatite (HAp), and titanium dioxide nanoparticles (Ti O 2 ). The study explores the microstructural characteristics of the composite material using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Samples of HDPE-30%HAp with varying concentrations of Ti O 2 (5, 10, 15, and 20%) were prepared and extruded using a twin-screw machine. The hybrid composite materials underwent mechanical tests (tensile, flexural, and hardness), tribological tests (friction and wear rate), and antibacterial tests (resistance to Escherichia coli and Staphylococcus aureus bacteria). The results indicate that the optimal hybrid composite sample was HDPE-30%HAP-10% Ti O 2 , which demonstrated excellent mechanical properties (maximum tensile strength of 25.93 MPa and young modulus of 480 MPa) and a low coefficient of friction (COF∼ 0.07) while achieving high wear resistance (wear rate in the order of 1 0 - 4   m m 3 N - 1  m - 1 ). The study shows that the improvement in mechanical properties results in a corresponding improvement in tribological properties. The antibacterial tests revealed that the hybrid composite material exhibited resistance to E. coli and S. aureus bacteria. The findings of this study suggest that the HDPE-30%HAP-10% Ti O 2 composite is a promising material for use in biomedical applications due to its excellent biocompatibility and desirable mechanical and tribological properties. The study demonstrates the potential of reinforced hybrid composite materials in overcoming the disadvantages of monolithic and hybrid micro-composites and highlights the importance of investigating the microstructural, tribological, and mechanical strength characteristics of composite materials for biomedical applications.

Fracture in the hip joint is a major and quite common health issue, particularly for the elderly. The loads exploited by the lower limbs are very acute and severe; in the femur, they can be several folds higher than the whole weight of the body. Nanotechnology and nanocomposites offer great potential in biomedical applications. The organic materials are more biocompatible. Mechanical properties like strength and hardness are challenging parameters which control the selection of a joint. HDPE in its pure form has been successfully used as a prosthetic foot (external) but failed as an implant material due to limited mechanical properties. High-density polyethylene thermoplastic polymer (HDPE) and multi-walled carbon nanotubes (MWCNT)/Nano-Alumina is selected as a potential material for a biomedical implant and its mechanical properties and biocompatibility have been discussed. HDPE/MWCNT/Alumina (Al 2 O 3 ) nanocomposites have not been explored yet for prosthetic implants. These nanocomposites were prepared in this investigation in different compositions. Prepared material has been physiochemically characterized to check the morphology and the structure. MWCNTs enhanced hardness and elastic modulus of the HDPE. Optimization of the material composition revealed that hybrid composite with structure (2.4% Al 2 O 3 and 0.6% MWCNT) exhibits better mechanical properties compared to other ratios with 3% MWCNTs and 5% MWCNTs. Thermal gravimetric analysis (TGA) dedicates that the percentage of crystallization has been increased to 6% after adding MWCNT to HDPE. The moisture absorption decreased to 90% with 5% MWCNT. Experimental results of Colorimetric assay (MTT) of a normal human epithelial cell line (1- BJ1) over Al 2 O 3 /MWCNT@HDPE showed <20% cytotoxic activity, proving its acceptance for medical use. HDPE/MWCNT/Al 2 O 3 nanocomposites emerged as a candidate material for artificial joints.