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The potential of improving the impact strength and reducing the density of carbon-fiber-composite products (CFCs) is explored as a function of the content of introduced ultra-high-molecular-weight polyethylene (UHMWPE) roving. The roving feature high tensile and impact strength and low density. The carbon fiber composite consists of carbon-fiber (CF) roving. It is additionally reinforced using D800 and SK75 roving with UHMWPE fibers. CF and UHMWPE roving are mixed in different ratios to make unidirectional hybrid (three-component) samples in two types of epoxy matrices (HT-2 and L285). In addition to hybrids, two-component samples are made using individual CF, D800, and SK75 roving. The amount of roving in the volume of hybrid samples is changed with a 25% increment to obtain CF and UHMWPE roving ratios of 0.25/0.75, 0.50/0.50 and 0.75/0.25. The required quantity of roving having the above ratios is calculated using the CF and UHMWPE roving constants. The impact strength, density and bending strength are estimated. The density of the samples is determined by calculation accounting for the roving constants. The results of the strength tests in hybrids are compared with CFC strength indicators. When the amount of UHMWPE roving increases, the bending strength and the density of hybrids decreases at different rates if compared to CF. The impact strength sharply increases under the same conditions followed by a sharp decline. The density of hybrids decreases by about 8% with each incremental step, and the rate of bending strength decline is approximately twice the rate of the density decrease. The impact strength of hybrids containing 25 and 50% UHMWPE roving shows an average increase by 3.28 and 3.4 times, respectively. [ABSTRACT FROM AUTHOR]

Aspects of solid‐state processing of nascent disentangled ultra‐high‐molecular‐weight polyethylene (UHMWPE) powders of different syntheses mixed with electrically conductive carbon nanoparticles (NPs) of various types are studied. Effect of multiple parameters of the processing procedures on the electrophysical characteristics of the composite samples is investigated. Such parameters include time of preliminary ultrasonication (US) of NPs, time of US of UHMWPE/NPs mixtures, molding time, temperature, and pressure, deformation degree, etc. It is observed that by selecting optimal values of such parameters it is possible to obtain samples of composites with an extremely segregated structure made of the NPs, with NPs distributed evenly on the surfaces of the compacted UHMWPE powder particles. This ensures high levels of conductivity at very low values of NPs content. The segregated structure is retained when the composites are strengthened using the solid‐state uniaxial shear deformation process. While conductivity of most of the composites filled with various types of NPs monotonously decreases with the deformation ratio, conductivity of the composites filled with exceptionally long double‐walled carbon nanotubes is maintained. The processed oriented composites are also characterized by high EMR shielding properties, as well as interesting temperature dependencies of the electrical conductivity. [ABSTRACT FROM AUTHOR]

This study investigates the static and dynamic mechanical properties of ultra-high-molecular-weight polyethylene (UHMWPE) fiber-reinforced concrete (FRC). The properties were assessed by conducting compressive strength, flexural strength, split tensile strength, and impact resistance. The pneumatic dispersion method was used for the UHMWPE fiber pretreatment. The concrete mix was prepared with a water-to-cement ratio of 0.6 and an aggregate fineness modulus of 5.39. UHMWPE fibers, measuring 6 mm and 12 mm in length and incorporated at addition rates of 5 wt‰, 10 wt‰, 15 wt‰, and 20 wt‰ of the fiber-to-cement weight ratio, were added to the concrete specimens for testing. The results showed that the FRC with 12 mm UHMWPE fiber and 15 wt‰ fiber-to-cement weight ratio achieved the best performance in the compressive strength test, and it increase 51.92 % compared with benchmark specimen. For the flexural test results, the 6 mm UHMWPR fiber performed best at a 15 wt‰ addition ratio, and it increase 18.77 % compared with benchmark specimen. Moreover, the FRC with 12 mm UHMWPR fiber excelled at a 20 wt‰ addition ratio in split tensile strength test, and it increase 92.14 % compared with benchmark specimen. The drop weight test indicated that a 15 wt‰ addition ratio with 12 mm UHMWPE fiber significantly enhanced performance, with an average impact number improvement of 5527 % under a 50 Joule impact energy, compared to the benchmark specimens. The study concludes that incorporating UHMWPE fiber into concrete significantly boosts its static and dynamic performance.

To improve the shock resistance of personal protective equipment and reduce casualties due to shock wave accidents, this study prepared four types of carbon fiber/polymethacrylimide (PMI) foam sandwich panels with different face/back layer thicknesses and core layer densities and subjected them to quasi-static compression, low-speed impact, high-speed impact, and non-destructive tests. The mechanical properties and energy absorption capacities of the impact-resistant panels, featuring ceramic/ultra-high molecular-weight polyethylene (UHMWPE) and carbon fiber/PMI foam structures, were evaluated and compared, and the feasibility of using the latter as a raw material for personal impact-resistant equipment was also evaluated. For the PMI sandwich panel with a constant total thickness, increasing the core layer density and face/back layer thickness enhanced the energy absorption capacity, and increased the peak stress of the face layer. Under a constant strain, the energy absorption value of all specimens increased with increasing impact speed. When a 10 kg hammer impacted the specimen surface at a speed of 1.5 m/s, the foam sandwich panels retained better integrity than the ceramic/UHMWPE panel. The results showed that the carbon fiber/PMI foam sandwich panels were suitable for applications that require the flexible movement of the wearer under shock waves, and provide an experimental basis for designing impact-resistant equipment with low weight, high strength, and high energy absorption capacities. [ABSTRACT FROM AUTHOR]

A new fluorine-containing OOO2−-type chelating ligand and the titanium(iv) dichloride and bis-isopropoxide complexes with this ligand were synthesized. The structure of the titanium(iv) bis-isopropoxide complex was determined by single-crystal X-ray diffraction analysis. In the presence of Al/Mg activators (Et2AlCl-Bu2Mg or Et3Al2Cl3-Bu2Mg), both complexes catalyze the ethylene polymerization giving ultra-high-molecular-weight polyethylene with a molecular weight of up to 5.8 • 106 Da. Due to a low degree of polymer entanglement, these polymers can be processed by a solvent-free method to prepare high-strength high-modulus films with a Young's modulus up to 117 GPa and a tensile strength up to 2.18 GPa. [ABSTRACT FROM AUTHOR]

In this study, the oxidative degradation of gamma-irradiated ultra-high-molecular-weight polyethylene (UHMWPE) was evaluated. Tensile yield stress, Young's modulus, and Vickers hardness were measured to characterize oxidative deterioration. Furthermore, we evaluated the existence of residual radicals by the electron spin resonance (ESR) analysis, and discussed the relationship between ESR spectra change and mechanical property indexes. In the tensile test of small UHMWPE specimens, it is often difficult to measure the strain. Therefore, we tried to estimate the Young's modulus simply by using Hertz's theory of elastic contact, and confirmed its usefulness. It is possible to estimate the tensile Young's modulus from the indentation test in this experimental range. This method is applicable to evaluate the relationship between mechanical properties such as Young's modulus and ESR properties over a long term after irradiation. [ABSTRACT FROM AUTHOR]

Moisture damage is a prevalent failure in asphalt pavements, which is directly linked to stripping and bitumen-aggregate adhesion. Also, it can lead to other main damages. This research aims to evaluate the adhesion and moisture susceptibility of asphalt mixes containing a new polymer additive namely ultra-high-molecular-weight polyethylene (UHMWPE) with 2 and 4% bituminous weight was performed. Moreover, the tensile strength ratio (TSR), boiling water test by the image processing of coating ratio ((CR) index), and surface free energy (SFE) were conducted and compared. The results indicated that adding 4% UHMWPE to the base bitumen (B-B) increased the 27% TSR index and 31% CR index compared to the base mixtures (without additive). The best performance in the mixture of limestone (LS) and bitumen was associated with 4% UHMWPE (LS-B-UHMWPE4), in which both TSR and CR indices had the highest values. The results of SFE components indicated that the free cohesion energy in modified bitumens has increased substantially by 65% compared to B-B. Additionally, the free adhesion energy in modified bitumens with limestone and granite has demonstrated higher values. The highest increase in TSR, CR, and SFE indices was observed in the modified mixture with LS-B-UHMWPE 4. [ABSTRACT FROM AUTHOR]

Pyomyositis is a bacterial infection occurring mainly in skeletal muscles. It is most commonly caused by Staphylococcus aureus with initial symptoms including muscle pain, swelling, and site tenderness. When available, the most accurate technique to determine the extent and the specific location of disease is the magnetic resonance imaging. Successful management includes early recognition, timely surgical debridement or drainage, and appropriate antibiotic therapy. This case report describes a case of Mycobacterium fortuitum pyomyositis in an elderly male associated with challenges of successful diagnosis.

Mechanochemically synthesized particles of two types of magnesium ferrites, one of which with structural distortions and an average size of 170 nm, and another that is highly crystalline with an average size of 900 nm, were introduced into a matrix of ultra-high-molecular-weight polyethylene via the milling processing. The final material has been formed by hot pressing mechanocomposites based on ultra-high-molecular-weight polyethylene and magnesium ferrite particles of various fineness and concentration. Structural characteristics were studied using scanning electron microscopy, differential scanning calorimetry and X-ray diffraction analysis. The dielectric properties of the obtained composites were analyzed by testing the frequency dependence of the permeability, dielectric losses, and conductivity. The effect of filler concentration and particle size, as well as the crystallinity of the polymer, on the dielectric properties of the composite material were studied.

In this study, air plasma and ZnO coating was used to modify ultra-high-molecular-weight polyethylene fibre (UHMWPE). The surface morphologies of the fibre with and without ZnO coating were examined under an electron scanning microscope (SEM), and the surface chemical composition was studied through X-ray spectroscopy. Moreover, the impact resistance and weight loss heat weight (TGA) of the fibre were examined. The results of this study indicated that the chemical activity of the fibre surface was enhanced due to the adsorption of O-C=O group, thus increasing the binding force between nano-ZnO coating and the fibre surface. A compact net-like nano-ZnO coating was identified on the fibre surface. The fibre pre-treated by plasma can be plated with more complete coatings, the thermal stability was enhanced by 19.7% after 120 s of treatment, and the impact resistance was significantly increased by 177% after 90 s of treatment. [ABSTRACT FROM AUTHOR]

Mechanochemically synthesized particles of two types of magnesium ferrites, one of which with structural distortions and an average size of 170 nm, and another that is highly crystalline with an average size of 900 nm, were introduced into a matrix of ultra-high-molecular-weight polyethylene via the milling processing. The final material has been formed by hot pressing mechanocomposites based on ultra-high-molecular-weight polyethylene and magnesium ferrite particles of various fineness and concentration. Structural characteristics were studied using scanning electron microscopy, differential scanning calorimetry and X-ray diffraction analysis. The dielectric properties of the obtained composites were analyzed by testing the frequency dependence of the permeability, dielectric losses, and conductivity. The effect of filler concentration and particle size, as well as the crystallinity of the polymer, on the dielectric properties of the composite material were studied. [ABSTRACT FROM AUTHOR]

To determine the maximum permissible load-speed modes of friction of ultra-high-molecular-weight polyethylene (UHMWPE) and composites based on it, accelerated wear tests were carried out, consisting in the intensification of friction modes (velocities and loads). The allowable load-speed modes of operation of UHMWPE and a composite based on it with 5 wt % carbon fiber of the Belum brand were experimentally established. For UHMWPE, they are 120–200 N m/s; for the composite, 160–250 N m/s. [ABSTRACT FROM AUTHOR]

To improve the shock resistance of personal protective equipment and reduce casualties due to shock wave accidents, this study prepared four types of carbon fiber/polymethacrylimide (PMI) foam sandwich panels with different face/back layer thicknesses and core layer densities and subjected them to quasi-static compression, low-speed impact, high-speed impact, and non-destructive tests. The mechanical properties and energy absorption capacities of the impact-resistant panels, featuring ceramic/ultra-high molecular-weight polyethylene (UHMWPE) and carbon fiber/PMI foam structures, were evaluated and compared, and the feasibility of using the latter as a raw material for personal impact-resistant equipment was also evaluated. For the PMI sandwich panel with a constant total thickness, increasing the core layer density and face/back layer thickness enhanced the energy absorption capacity, and increased the peak stress of the face layer. Under a constant strain, the energy absorption value of all specimens increased with increasing impact speed. When a 10 kg hammer impacted the specimen surface at a speed of 1.5 m/s, the foam sandwich panels retained better integrity than the ceramic/UHMWPE panel. The results showed that the carbon fiber/PMI foam sandwich panels were suitable for applications that require the flexible movement of the wearer under shock waves, and provide an experimental basis for designing impact-resistant equipment with low weight, high strength, and high energy absorption capacities.

A novel approach to the preparation of a hard-elastic polymeric material based on ultra-high-molecular-weight polyethylene using the strategy of crazing of polymers was proposed. This approach comprises the process of deformation of the pristine films of ultra-high-molecular-weight polyethylene via the environmental intercrystallite crazing mechanism and the subsequent low-temperature spontaneous strain recovery upon stress relaxation. As a result, the material acquires new properties typical of hard-elastic materials: restoration of the porous structure with pore sizes in the nanometer range (less than 10 nm) after the secondary deformation in air up to ~20 vol %, high reversibility of deformation (50–85%), and the effect of opening and closing of pores under cyclic loading. The mechanism of this phenomenon was proposed, and the fields of practical applications of this kind of mechanosensitive material were indicated. [ABSTRACT FROM AUTHOR]

The surface treatment of ultra-high-molecular-weight polyethylene (UHMWPE) in helium plasma at a pressure of 0.133 mbar has been studied by IR spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. It has been shown that the helium plasma treatment leads to the formation of double bonds in the UHMWPE surface layer and the associated formation of intermolecular crosslinks. The crosslinking of the surface layer is accompanied by a decrease in the nanowear of the UHMWPE surface by more than three orders of magnitude, which is confirmed by measurements using an atomic force microscope in the contact mode. [ABSTRACT FROM AUTHOR]

Ultra-high-molecular-weight polyethylene (UHMWPE) wear and particle-induced osteolysis contribute to the failure of total hip arthroplasty (THA) and total knee arthroplasty (TKA). Highly crosslinked polyethylene (HXLPE) was developed in the late 1990s to reduce wear and has shown lower wear rates and loosening than conventional UHMWPE in THA. The irradiation dose for crosslinking is up to 100 kGy. However, during crosslinking, free radical formation induces oxidation. Using HXLPE in THA, the cumulative revision rate was determined to be significantly lower (6.2%) than that with conventional UHMWPE (11.7%) at a mean follow-up of 16 years, according to the Australian Orthopaedic Association National Joint Replacement Registry. However, HXLPE does not confer to TKA the same advantages it confers to THA. Several alternatives have been developed to prevent the release of free radicals and improve polymer mechanical properties, such as thermal treatment, phospholipid polymer 2-methacryloyloxyethyl phosphorylcholine grafting, remelting, and vitamin E addition. Among these options, vitamin E addition has reported good clinical results and wear resistance similar to that of HXLPE without vitamin E, as shown by short-term clinical studies of THA and TKA. This review aims to provide a comprehensive overview of the development and performance of UHMWPE in THA and TKA. [ABSTRACT FROM AUTHOR]

For Japanese individuals, deep bending is inevitable in their daily lives, such as during seiza sitting and kneeling. Thus, achieving a good post-operative range of motion is an important factor in improving patient satisfaction. Even normal knees often have a posterior tibial slope of more than 10°. We report the case of a 76-year-old woman who underwent proximal tibial osteotomy at 8° with the Vanguard Knee cruciate retaining total knee arthroplasty (TKA) system. She required the revision TKA 10 years later due to ultra-high-molecular-weight polyethylene wear and breakage of the posteromedial tibial component. [ABSTRACT FROM AUTHOR]

Hybridisation is the process of reinforcing multiple fibres in a single matrix. Hybridisation has proved to enhance the mechanical strength of composites based on natural fibres and has opened avenues for using these composites in applications such as structural members for office partitions, automotive interior panels and sound proof panels. Present study deals with the hybridisation of natural fibres such as flax and jute with a synthetic fibre ultra-high-molecular-weight polyethylene (UHMWPE), using melamine formaldehyde resin. Hand lay-up and compression moulding process was used to fabricate eight layered composite panels with six different fibre orientation. In this study, the effect of stack sequence on flexural, impact and inter laminar shear strength was investigated. Maximum flexural strength of (36.07 MPa), inter laminar shear strength of (3.81 MPa) and impact strength of (63.83 kJ/m2) was noted for Stack-2 hybrid composites. Stack-4 composites with flexural strength of (18.96 MPa), inter laminar shear strength of (2.19 MPa) and impact strength of (24.61 kJ/m2) was the lowest. Analysis of the composite failure mechanisms was carried out using Cone Beam Computed Tomography (CBCT). Failure mechanisms such as angular bending, deformation, peripheral shearing, debonding and delamination were prominent. [ABSTRACT FROM AUTHOR]

The aim of the study is the development of two-layer materials based on ultra-high-molecular-weight polyethylene (UHMWPE) and isoprene rubber (IR) depending on the vulcanization accelerators (2-mercaptobenzothiazole (MBT), diphenylguanidine (DPG), and tetramethylthiuram disulfide (TMTD)). The article presents the study of the influence of these accelerators on the properties and structure of UHMWPE. It is shown that the use of accelerators to modify UHMWPE leads to an increase in tensile strength of 28–53%, a relative elongation at fracture of 7–23%, and wear resistance of three times compared to the original UHMWPE. It has been determined that the introduction of selected vulcanization accelerators into UHMWPE leads to an increase in adhesion between the polymer and rubber. The study of the interfacial boundary of a two-layer material with scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) showed that the structure is characterized by the presence of UHMWPE fibrils localized in the rubber material due to mechanical adhesion. [ABSTRACT FROM AUTHOR]

Background: Patients with total knee arthroplasty (TKA) stiffness are commonly presumed to have arthrofibrosis though no specific test exists. In patients undergoing revision TKA, we asked the following question: (1) Do patients who are revised for stiffness display a synovial reaction on MRI that is different than patients revised for other reasons? (2) Do these patients have a different magnitude of polyethylene insert damage than patients revised for other reasons? and (3) Is the MRI synovial classification associated with polyethylene insert damage?Methods: Patients undergoing revision TKA for stiffness had a preoperative MRI performed, and the synovium was classified on MRI in a blinded fashion as arthrofibrosis, focal scarring, polymeric reaction, infection, or abnormal. At surgery, the polyethylene inserts were removed, and graded by 2 reviewers for total surface damage.Results: Revision indication and MRI synovial classification were associated (P < .0001), with a greater proportion of patients assigned an MRI classification of arthrofibrosis revised for arthrofibrosis and a greater proportion of patients assigned a polymeric classification revised for aseptic loosening. Patients assigned an MRI synovial classification of polymeric had the greatest damage to the tibial insert (P < .0001), and patients revised for the clinical indication of aseptic loosening had the greatest damage to the tibial insert (P < .0001).Conclusion: Synovial grading on MRI is strongly associated with revision indication and polyethylene insert damage. In patients with stiffness in the absence of another complication, MRI can be a helpful diagnostic adjuvant in confirming the diagnosis of stiffness. [ABSTRACT FROM AUTHOR]

Ultra-high-molecular-weight polyethylene (UHMWPE) wear and particle-induced osteolysis contribute to the failure of total hip arthroplasty (THA) and total knee arthroplasty (TKA). Highly crosslinked polyethylene (HXLPE) was developed in the late 1990s to reduce wear and has shown lower wear rates and loosening than conventional UHMWPE in THA. The irradiation dose for crosslinking is up to 100 kGy. However, during crosslinking, free radical formation induces oxidation. Using HXLPE in THA, the cumulative revision rate was determined to be significantly lower (6.2%) than that with conventional UHMWPE (11.7%) at a mean follow-up of 16 years, according to the Australian Orthopaedic Association National Joint Replacement Registry. However, HXLPE does not confer to TKA the same advantages it confers to THA. Several alternatives have been developed to prevent the release of free radicals and improve polymer mechanical properties, such as thermal treatment, phospholipid polymer 2-methacryloyloxyethyl phosphorylcholine grafting, remelting, and vitamin E addition. Among these options, vitamin E addition has reported good clinical results and wear resistance similar to that of HXLPE without vitamin E, as shown by short-term clinical studies of THA and TKA. This review aims to provide a comprehensive overview of the development and performance of UHMWPE in THA and TKA.

Introduction. Currently, in various technology areas, bronze, cast iron and other antifriction metals are replaced by polymer composites, which extend significantly service life of tribocoupling. An advanced antifriction polymer is ultra-high-molecular-weight polyethylene. The study deals with determining the optimal specific energy consumption for the mechanical activation of the polymer dry mixed powders and nanomodifiers in the planetary ball mill Pulverisette 7, which ensure the best complex of physico-mechanical and rheological properties of nanocomposites. Materials and Methods. In this work, we used GUR 4120 Ticona ultra-high-molecular-weight polyethylene with a molecular weight of 5 million, a Tuball Matrix Beta concentrate of activated carbon nanotubes at a concentration of 0.1%, calculated with reference to carbon nanotubes, and hydrophobic nanocrystalline silicon dioxide with a dispersion of 20 nm at the same concentration. Mechanical co-activation of polymer powders and nanomodifiers, when varying the specific energy consumption, was carried out in the planetary ball mill Pulverisette 7. The production of films from powders, for studying the elastic-strength and rheological characteristics of nanocomposites, was carried out with the use of the hydraulic press Gibitre. Tests were carried out respectively on the tensile testing machine UAI-7000 M and the rheometer Haake MARS III. Results. It has been established that the best physico-mechanical and rheological properties of nanocomposites are with specific energy consumption for mechanical activation of 3,000‒3,200 J/g that allows us to consider them optimal. The mechanical activation of ultra-high-molecular-weight polyethylene powder, reducing slightly the elasticity modulus and tensile strength of thermally pressed samples, does not affect the dynamic viscosity of melts at an energy consumption of 650‒4,550 J/g. Discussion and Conclusion. The use of carbon nanotubes and nanocrystalline silicon dioxide at a concentration of 0.1% can significantly improve the physical-mechanical and rheological properties of the polymer with energy costs of 3,000‒3,200 J/g for mechanical activation in planetary ball mills. Nanocrystalline silicon dioxide is a more effective modifier that can be explained by its better dispersion in the polymer matrix due to the lower tendency of nanoparticles to agglomerate.

Organic-inorganic nanocomposite materials based on high-density polyethylene and ultra-high-molecular weight polyethylene have been prepared via different methods of silver ions reduction to silver within confined space. The resultant materials have revealed uniform distribution of silver nanoparticles, and their size has been controlled by the reduction method. Silver nanoparticles with high surface/volume ratio have been obtained under mild conditions of reduction. Silver-containing nanocomposites have shown high antibacterial activity and can be used as efficient materials for biomedical purposes. [ABSTRACT FROM AUTHOR]

The aim of this study is to compare magnetic resonance imaging (MRI) with computed tomography (CT) for visualization of an orbital alloplastic prosthesis made of ultra-high-molecular-weight polyethylene (UHMW-PE) both in vitro and in vivo. A study of 15 test implants from UHMW-PE visualized in vitro in CT and MRI and an in vivo visualization in a patient who suffered from orbital injury and underwent reconstructive surgery is presented. The postsurgery MRI showed the UHMW-PE material clearly, with no significant artifacts. The surrounding tissues could be satisfactorily evaluated. The CT scans did not present the graft material. Both techniques were sufficient tools for in vitro evaluation of the shape and measurement of the prosthesis. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (GNPs) was utilized to improve shape recovery rate (Rr) of ultra-high-molecular-weight polyethylene (UHMWPE) by compression molding technology. The results show that the melting temperature (Tm) and crystallinity of specimens are decreased, while the mechanical property is improved significantly. Additionally, shape memory behavior of UHMWPE nanocomposites is improved effectively, and the optimal shape memory effect with the shape fixity ratio (Rf) of about 95% and the Rr of about 97% was obtained. Meanwhile, the relationship among shape memory characteristics and microstructure, thermal and mechanical properties was analyzed. Besides, two kinds of shape memory testing methods, the bending test with a custom technique and the cyclic tensile test under DMA controlled strain mode, obtained the same trend and different values of Rf and Rr.

Artificial hip joint (AHJ) hailed as the current best solution to solve the damage hip joint issues that can lead to permanent disability. This study investigates the performance of artificial hip joint during the salat activity under seven salat position loading condition by introducing the existence of non-Newtonian synovial fluid and analyzed with two-way FSI methods. Based on the result, the amount of hydrodynamic pressure is affected by the external and internal rotation (z-axis) position. The external position enhances the hydrodynamic pressure value, while the internal position reduces the hydrodynamic pressure value. Meanwhile, the maximum equivalent stress on the inner liner under all salat position is insignificant to the elastic modulus of the Ultra-high-molecular-weight polyethylene (UHMWPE) therefore the artificial hip joint is statically safe to perform salat. Finally, the amount of load support is insufficient to prevent the direct contact between the femoral head and inner liner. Thus, the design modification is necessary to provide the sufficient value of load support on the artificial joint.

The aim of the study is the development of two-layer materials based on ultra-high-molecular-weight polyethylene (UHMWPE) and isoprene rubber (IR) depending on the vulcanization accelerators (2-mercaptobenzothiazole (MBT), diphenylguanidine (DPG), and tetramethylthiuram disulfide (TMTD)). The article presents the study of the influence of these accelerators on the properties and structure of UHMWPE. It is shown that the use of accelerators to modify UHMWPE leads to an increase in tensile strength of 28–53%, a relative elongation at fracture of 7–23%, and wear resistance of three times compared to the original UHMWPE. It has been determined that the introduction of selected vulcanization accelerators into UHMWPE leads to an increase in adhesion between the polymer and rubber. The study of the interfacial boundary of a two-layer material with scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) showed that the structure is characterized by the presence of UHMWPE fibrils localized in the rubber material due to mechanical adhesion.

In this study, the ballistic impact behavior of auxetic sandwich composite human body armor was analyzed using finite element analysis. The auxetic core of the armor was composed of discrete re-entrant unit cells. The sandwich armor structure consisted of a front panel of aluminum alloy (Al 7075-T6), UHMWPE (sandwich core), and a back facet of silicon carbide (SiC) bonded together with epoxy resin. Numerical simulations were run on Explicit Dynamics/Autodyne 3-D code. Various projectile velocities with the same boundary conditions were used to predict the auxetic armor response. These results were compared with those of conventional monolithic body armor. The results showed improved indentation resistance with the auxetic armor. Deformation in auxetic armor was observed greater for each of the cases when compared to the monolithic armor, due to higher energy absorption. The elastic energy dissipation results in the lower indentation in an auxetic armor. The armor can be used safely up to 400 m/s; being used at higher velocities significantly reduced the threat level. Conversely, the conventional monolithic modal does not allow the projectile to pass through at a velocity below 300 m/s; however, the back face becomes severely damaged at 200 m/s. At a velocity of 400 m/s, the front facet of auxetic armor was destroyed; however, the back facet was completely safe, while the monolithic panel did not withstand this velocity and was completely damaged. The results are encouraging in terms of resistance offered by the newly adopted auxetic armor compared to conventional monolithic armor.

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One of the effective parameters in the occurrence of fatigue cracking distress is the asphalt binder properties used, which must be controlled by appropriate asphalt binder or additives. In this study, the effect of using Ultra-High-Molecular-Weight Polyethylene (UHMWPE) was investigated on the fatigue cracking potential of asphalt mixtures. Two types of aggregates, asphalt binder performance grade (PG) 64-16, and UHMWPE additive in two percent of the asphalt binder were used in this study, which were tested at two temperatures and five different stress levels. Marshall mix design and indirect tensile fatigue test (ITFT) were used to determine the optimum content of the asphalt binder and the fatigue life of asphalt mixtures, respectively. The results of this study indicated that the application of polymer additives increased the fatigue life of the asphalt mixtures. The fatigue life of specimens made with granite aggregates was longer than those made with limestone aggregates, and the increased life due to the use of UHMWPE was longer in samples made with granite aggregates. As expected, increasing in temperature and stress levels reduced the fatigue life of the asphalt mixtures. This decrease was much lower in samples made of asphalt binder modified with polymeric materials than in control samples. [ABSTRACT FROM AUTHOR]

The development of new porous polymeric materials with nanoscale pore dimensions and controlled morphology presents a challenging problem of modern materials and membrane science, which should be based on scientifically justified approaches with the emphasis on ecological issues. This work offers a facile and sustainable strategy allowing preparation of porous nanostructured materials based on ultra-high-molecular-weight polyethylene (UHMWPE) via the mechanism of environmental intercrystallite crazing and their detailed characterization by diverse physicochemical methods, including SEM, TEM, AFM, liquid and gas permeability, DSC, etc. The resultant porous UHMWPE materials are characterized by high porosity (up to ~45%), pore interconnectivity, nanoscale pore dimensions (below 10 nm), high water vapor permeability [1700 g/(m2 × day)] and high gas permeability (the Gurley number ~300 s), selectivity, and good mechanical properties. The applied benefits of the advanced UHMWPE mesoporous materials as efficient membranes, breathable, waterproof, and insulating materials, light-weight materials with reduced density, gas capture and storage systems, porous substrates and scaffolds are discussed.

Poly(p-phenylene terephthalamide) (PPTA) is a high-performance polymer that has been utilized in a range of applications. Although PPTA fibers are widely used in various composite materials, laminar structures consisting of PPTA and ultra-high-molecular-weight polyethylene (UHMWPE), are less reported. The difficulty in making such composite structures is in part due to the weakness of the interface formed between these two polymers. In this study, a layered structure was produced from PPTA fabrics and UHMWPE films via hot pressing. To improve the interlayer adhesion, oxygen plasma was used to treat the PPTA and the UHMWPE surfaces prior to lamination. It has been found that while plasma treatment on the UHMWPE surface brought about a moderate increase in interlayer adhesion (up to 14%), significant enhancement was achieved on the samples fabricated with plasma treated PPTA (up to 91%). It has been assumed that both surface roughening and the introduction of functional groups contributed to this improvement.

The data included here provides a basis for understanding “Interior morphology of high-performance polyethylene fibers revealed by modulus mapping” (K.E. Strawhecker, E.J. Sandoz-Rosado, T.A. Stockdale, E.D. Laird, 2016) [1], in specific: the multi-frequency (AMFM) atomic force microscopy technique and its application to ultra-high-molecular-weight Polyethylene (UHMWPE) fibers. Furthermore, the data suggests why the Hertzian contact mechanics model can be used within the framework of AMFM theory, simple harmonic oscillator theory, and contact mechanics. The framework is first laid out followed by data showing cantilever dynamics, force-distance spectra in AC mode, and force-distance in contact mode using Polystyrene reference and UHMWPE. Finally topography and frequency shift (stiffness) maps are presented to show the cases where elastic versus plastic deformation may have occurred.

Total joint replacement is a widely used and successful surgical approach. Approximately 7 million US adults are currently living with a hip or knee replacement. However, the surgical procedures for total joint replacement are associated with significant postoperative pain, and current strategies do not adequately address this pain, which leads to patient dissatisfaction, reduced mobility, and increased risk of opioid addiction. We hypothesized that the ultra-high-molecular-weight polyethylene (UHMWPE) bearing surfaces used in total joint prosthetics could provide sustained release of the local anesthetic bupivacaine to provide relief from joint pain for an extended period of time after surgery. In this paper, we describe the production of bupivacaine-loaded UHMWPE (BPE) and measure the in vitro bupivacaine release kinetics of BPE. We found that bupivacaine could be released from BPE at clinically relevant rates for up to several days and that BPE possesses antibacterial effects. Therefore, bupivacaine-loaded UHMWPE is a promising material for joint replacement prostheses, and future studies will evaluate its safety and efficacy in in vivo models. Total joint replacement is associated with significant pain and risk of infection. In our paper, we introduce bupivacaine-loaded ultra-high-molecular-weight polyethylene (BPE), which releases bupivacaine, a pain-treating drug, at doses comparable to currently used doses. Additionally, BPE inhibits the growth of infection-causing bacteria. Therefore, BPE may be able to reduce both postsurgical pain and risk of infection, potentially treating two of the most prominent complications associated with total joint replacement. To our knowledge, this is the first development of a material that can address both complications, and devices incorporating BPE would represent a significant advancement in joint arthroplasty prosthetics. More generally, the incorporation of therapeutic agents into ultra-high-molecular-weight polyethylene could impact many orthopedic procedures owing to its ubiquity. [ABSTRACT FROM AUTHOR]

The study of processing characteristic and property optimization of ultra-high-molecular-weight polyethylene (UHMWPE) pipe is increasingly performed, mainly focusing on difficulties in the melting process and poor thermal-mechanical properties after forming, which have limited the wider engineering application of UHMWPE pipe. In this study, organo-montmorillonite (OMMT)-modified UHMWPE pipe with good thermal-mechanical properties was prepared by screw extrusion molding. First, high-density polyethylene was subjected to fluidity modification so that the screw extrusion molding of UHMWPE pipe was feasible. Then, OMMT-modified UHMWPE pipes under different addition amounts of OMMT were innovatively prepared by extrusion. Furthermore, the effects of the addition amounts of the compatibilizer HDPE-g-MAH and the silane coupling agent γ-(2,3-epoxy propoxy) propyl trimethoxy silane (KH560) on the thermal properties of OMMT-modified UHMWPE pipe were investigated for the first time. Compared with those of pure UHMWPE pipe, the Vicat softening temperature (from 128 to 135.2 °C), thermal deformation temperature (from 84.4 to 133.1 °C), bending strength (from 27.3 to 39.8 MPa), and tensile strength (from 20.8 to 25.1 MPa) of OMMT-modified UHMWPE pipe were greatly increased. OMMT-modified UHMWPE pipe with good thermal-mechanical properties was able to be prepared by extrusion for the first time. The compatibilizer method of HDPE-g-MAH was slightly more effective than the coupling agent method of KH560.

In this study, a facile and effective method is adopted to prepare mechanochemically robust super antifouling membrane surfaces. During the process, vinyl trimethoxy silane (VTMS) was used as the reactive intermediate for coupling the hydrophilic inorganic SiO2 nanoparticle layer on to the organic ultra-high-molecular-weight polyethylene (UHMWPE) membrane surface, which created hierarchical nanostructures and lower surface energy simultaneously. The physical and chemical properties of the modified UHMWPE composite membrane surface were investigated. FTIR and XPS showed the successful chemical grafting of VTMS and SiO2 immobilization, and this modification could effectively enhance the membrane’s surface hydrophilicity and filtration property with obviously decreased surface contact angle, the pure water flux and bovine serum albumin (BSA) rejection were 805 L·m−2·h−1 and 93%, respectively. The construction of the hydrophilic nano-SiO2 layer on the composite membrane surface for the improvement of membrane antifouling performance was universal, water flux recovery ratio values of BSA, humic acid (HA), and sodium alginate (SA) were all up to 90%. The aim of this paper is to provide an effective approach for the enhancement of membrane antifouling performance by the construction of a hydrophilic inorganic layer on an organic membrane surface.

Ultra-high-molecular-weight polyethylene (UHMWPE) reinforced with carbon fibre (CF) and filled with polyphenyl ester (POB) and nanosized copper (Cu) fillers was prepared by compression moulding. The tribological behaviours and the synergism of the incorporation of fibre and particulates were studied. The proportions of the reinforcement material ranged from 5 wt% to 25 wt%, the filler material of POB varied from 5 wt% to 25 wt% and the nanosized filler was from 4 wt% to 12 wt%. In the sample with CF only, the lowest wear rate was observed for the UHMWPE + 15% CF composite. The particulate filler further reduced the composite wear rate, and the lowest wear rate was found for the hybrid with CF, POB and nanosize Cu particles, that is, for the UHMWPE + 15% CF + 15% POB + 12% Cu composite. The particulate filler was added, and the coefficient of friction slightly increased. The transfer film formed on the metal counterface was studied using optical microscopy, and the topography of the transfer film was investigated using atomic force microscopy. Results showed that the transfer films were thin, compact and uniform on the metal counterfaces of the UHMWPE + 15% CF + 15% POB + 12% Cu composite. Worn surface morphologies of composites were studied using scanning electron microscopy. Results showed that the worn surface of the UHMWPE + 15% CF + 15% POB + 12% Cu composite was smoother and had better wear resistance than that of other composites. [ABSTRACT FROM AUTHOR]

The tribological properties and wear resistance under different action of composite materials based on of ultra-high-molecular-weight polyethylene (UHMWPE) and fillers of various types such as organomodified montmorillonite (MMT), graphite nanoplates (GNP), molybdenum disulfide, and shungite prepared via polymerization in situ are studied. According to the obtained results, the introduction of these fillers to UHMWPE in the amount of 0.4-7 wt % has almost no effect on the value of the coefficient of sliding friction on steel in the mode of dry friction. Composites with GNP, MoS2, and shungite are characterized by a significant (two- to threefold) increase in the wear resistance in the case of sliding friction on steel. The abrasive wear of composites in the case of friction on an abrasive paper is substantially affected by the type of filler, the use of MMT was the most effective for increasing the wear resistance of composites. In the case of a highspeed impact effect of water-sand suspensions all the studied composites are characterized by increased wear resistance in comparison with industrial UHMWPE at a low concentration of fillers and by an increase in the wear with the increase of the filler content. [ABSTRACT FROM AUTHOR]

This investigation examines the influence of fiber type on the failure of titanium-based fiber metal laminates (FMLs). Two types of FMLs, comprising fiber-based composite layers, sandwiched between titanium sheets, were subjected to impact by a 12 mm steel sphere at various velocities ranging from 100–400 m/s. The first FML incorporated carbon fiber reinforced plastic (CFRP) layers, whereas the second had hot-pressed ultra-high-molecular-weight polyethylene fiber (UHMWPE, Dyneema ® HB50) layers as the sandwiched component. FML specimens were clamped between annular plates, which exposed a circular target, and impacted at the center by spherical projectiles. Optical images of the deformation and failure induced in the two types of FMLs were captured by a high-speed camera, and the respective responses compared; the ballistic limit and energy absorbed were also determined. The results indicate that the ballistic performance of the Ti/HB50 system is superior to the Ti/CFRP combination, in terms of ballistic limit and energy absorption. However, this difference diminishes when the impact velocity exceeds 1.5 times the ballistic limit. The rolling direction of the titanium sheet plays a significant role in the amount of energy absorbed, through its influence on the deformation/failure mode of the FMLs. [ABSTRACT FROM AUTHOR]