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In this work, a morphology transition mode is revealed in ultra-high molecular weight polyethylene (UHMWPE) when stretching at 120 °C: moving from the slightly deformed region to the necked region, the morphology transfers from small spherulites to a mixture of transcrystalline and enlarged spherulites, and finally to pure transcrystalline; meanwhile, the lamellae making up the transcrystalline or spherulite were fragmented into smaller ones; spatial scan by wide-angle X-ray scattering (WAXS) and small angle X-ray scattering (SAXS) revealed that the crystallinity is increased from 25.3% to 30.1% and the crystal orientation was enhanced greatly, but the lamellae orientation was quite weak. The rise of enlarged spherulites or a mixture of transcrystalline and spherulites can also be found in UHMWPE stretched at 140 and 148 °C, whereas absent in UHMWPE stretched at 30 °C. In situ WAXS/SAXS measurements suggest that during stretching at 30 °C, the crystallinity is reduced drastically, and a few voids are formed as the size increases from 50 nm to 210 nm; during stretching at 120 °C, the crystallinity is reduced only slightly, and the kinking of lamellae occurs at large Hencky strain; during stretching at 140 and 148 °C, an increase in crystallinity with stretching strain can be found, and the lamellae are also kinked. Taking the microstructure and morphology transition into consideration, a mesoscale morphology transition mode is proposed, in the stretching-induced crystallization the fragmented lamellae can be rearranged into new supra-structures such as spherulite or transcrystalline during hot stretching. [ABSTRACT FROM AUTHOR]

In this work, the effect of an acidic environment on the structure of composite samples based on ultra-high molecular weight polyethylene (UHMWPE) modified with mineral filler in the form of diabase (DB) is studied. The stability of samples was investigated in solutions of sulfuric (H₂SO₄) and hydrochloric (HCl) acids with concentrations of 10 vol% and 20 vol% at room temperature for 16 weeks. It was found that the introduction of 10 wt% DB into the UHMWPE matrix significantly increases the resistance of the composite sample to aggressive media, which is confirmed by the minimum degree of swelling compared to pure UHMWPE and composites with higher filler content. Scanning electron microscopy (SEM) demonstrated a uniform distribution of DB in the sample structure and the absence of defects such as agglomeration and cracks. The methods of infrared spectroscopy (IRS) and X-ray structural analysis (XRD) revealed a decrease in the degree of crystallinity of the samples after acid exposure, but no significant changes in the chemical structure of the materials were recorded, which confirms their resistance to chemical degradation. The best chemical resistance was demonstrated by composites containing 10 wt% DB, which is associated with the formation of a barrier structure preventing the diffusion of acids. The obtained results indicate the promising application of UHMWPE with DB filler to create samples resistant to aggressive media. [ABSTRACT FROM AUTHOR]

The molecular characteristics and rheological properties of three UHMWPE samples were investigated. The high-temperature GPC method was used for characterizing UHMWPE samples used. The interpretation of the measurement results was based on calibration using the PS standard and the approximation of the PS data by linear and cubic polynomials, as well as on the data for linear PE. The assessment of the average MW and MWD depends on the choice of calibration method, so that different methods give different results. Only the results obtained using PS with cubic approximation are close to the characteristics offered by the manufacturer. It was also shown that the obtained MW characteristics depend on the dissolution time. The reason for this may be the presence of any processing-aid compounds or destruction of macromolecules. Measurements of the rheological properties were performed in creep modes for a wide range of shear stresses and harmonic oscillations. It was shown that even at 210 °C, UHMWPE does not flow, and the observed irreversible deformations are due to the plasticity of the polymer, i.e., UHMWPE is in an elastic–plastic state. The ultimate plastic deformations drop sharply with increasing MW of the polymer. The plasticity modulus for the highest molecular weight UHMWPE samples does not depend on stress. Measurements of viscoelastic characteristics confirmed that the terminal region of viscous flow cannot be reached under any conditions. Increasing the duration of holding the polymer at high temperature leads not to flow, but to the destruction of macromolecules. [ABSTRACT FROM AUTHOR]

Ultra-high-molecular-weight polyethylene (UHMWPE) is often considered an ideal reinforcing material due to its extraordinary characteristics like high abrasion resistance, excellent toughness, and chemical stability. However, the poor surface properties have significantly hindered the progress of UHMWPE with high performance. This review is intended to introduce the physicochemical mechanisms of UHMWPE interfacial property modification. Therefore, this review provides a concise overview of the progress in diverse surface modification techniques for UHMWPE and their strengths and limitations as polymer reinforcement materials. Lastly, an overview of the potential and challenges of each surface modification has been summarized. [ABSTRACT FROM AUTHOR]

Purpose: Despite there being different materials for orbital floor reconstruction available today, outcomes are still not satisfying. In recent years, ultra-high molecular weight polyethylene (UHMWPE) has gained popularity in the field of orthopedic surgery due to its good biocompatibility and low infection rate. With its three-dimensional compound structure, it combines high stability and ductility, making it a potential material to be used for orbital floor reconstruction. Methods: In a cadaver study, an overall of eighteen orbits were included. Fractures of the inferior wall were induced and then reconstructed using Polyglactin 910/PDS composite (Ethisorb) and UHMWPE (marPOR). Orbits were scanned by cone-beam CT in each condition: Intact, fractured and reconstructed with Ethisorb, marPOR 0.85 mm and marPOR 1.5 mm. Segmented orbital volumes were calculated by specialized software (Disior bonelogic CMF). Results: All materials led to sufficient reconstruction of the initial orbital volumes (Ethisorb: p < 0.001; marPOR 0.85 mm: p = 0.003; marPOR 1.5 mm: p < 0.001). Orbits that were reconstructed with marPOR 0.85 mm showed the least mean volume difference from intact orbital volumes. Conclusion: UHMWPE (marPOR) offers reliable reconstruction of orbital floor fractures combined with good stability, ductility and biocompatibility. [ABSTRACT FROM AUTHOR]

The impact of different concentrations of natural antioxidants (curcumin) on the thermal stability of UHMWPE (ultra-high molecular weight polyethylene) is examined via the thermogravimetric (TGA/DTA) technique, in the temperature region 50–600 °C at a 5 °C/min heating rate. This work employs the model fitting (Coats and Redfern) approach to determine the optimal curcumin concentration. UHMWPE samples at optimum concentration are further subjected to three other heating rates, viz., 10, 15 and 20 °C. A bi-Gaussian asymmetric function is utilized for deconvolution to elucidate the complexities of thermal decomposition. Through deconvolution, two peaks are obtained and the activation energy corresponding to each peak is determined through two iso-conversional kinetic (Friedman and Starink) models. By utilizing activation energy, the random nucleation reaction mechanism involved in thermal decomposition is recognized. Finally, changes in entropy Δ S , enthalpy Δ H and Gibbs free energy Δ G are determined. [ABSTRACT FROM AUTHOR]

Ultra-high molecular weight polyethylene (UHMWPE) is utilised for several purposes, including as a biomedical material for artificial joint replacement. This study looks at the effects of adding nanosized hydroxyapatite (HAP), nanosized titanium dioxide (TiO2), carbon fibre (CF), and Kevlar fibre (KF) to bone plate fixation in the femur bone prosthesis. Because of the ease with which they could be processed, their low cost, remarkable mechanical properties, good cell interaction, different amounts of n-HAP and n-TiO2 (1.5, 2.5, 3.5, and 4.5 wt%), and a fixed amount of CF and KF (5 wt%) were dispersed in UHMWPE-based biocomposites. The UHMWPE/n-HAP and UHMWPE/n-TiO2 particulate biocomposites were prepared by using the dispersing technique followed by hot pressing moulding, then mechanical testing was performed, including flexural, maximum shear stress, and impact tests. Scanning electron microscopy (SEM) is used to observe reinforcement and matrix fractures. Biocomposites with n-HA/Carbon fibre hybrid biocomposites showed better results concerning specific mechanical strength, as well as flexural strength, max. shear and impact energy. The composites show an increase in flexural strength, flexural modulus, impact strength, and max. shear stress by 44%, 32.49%, 120.7%, and 182.6% respectively concerning neat UHMWPE. This review focuses on the benefits of UHMWPE particulate biocomposites in a variety of weight proportions and hybrid biocomposites, which have not yet been tested as a superior alternative for the creation of bone plate fixation. [ABSTRACT FROM AUTHOR]

This study examines the high‐strain rate behavior of shear thickening fluid (STF)‐encapsulated samples of an electrospun mat. It comprises sandwich layers of STF‐impregnated ultra‐high molecular weight polyethylene (UHMWPE)/high‐density polyethylene (HDPE) mat enclosed within high‐temperature stretched electrospun neat UHMWPE fabric. The UHMWPE/HDPE mat was chosen for STF impregnation due to its porosity and the texture of its fiber surface, which contains pores, pits, wrinkles, and grooves ranging in size from nano‐ to micron‐scale. This feature enhances the adhesion and absorption of STF into the fiber structure and onto the fiber surface. These STF‐contained and corresponding neat samples were tested using an in‐house‐designed split‐Hopkinson pressure bar. The deformation and fracture behavior of samples were also monitored simultaneously using a high‐speed camera. The results showed that at a higher strain rate, the peak stress and energy absorption of STF‐encapsulated samples were more elevated due to increased inter‐fiber friction, unlike neat samples, which show a declining trend in peak stress and energy absorption due to yarn slippage. Moreover, the deformation during impact in neat samples was higher than in the STF‐encapsulated samples. Highlights: Electrospun ultra‐high molecular weight polyethylene and its HDPE blended fibersInterconnected pores and pits facilitated shear thickening fluid (STF) impregnation.STF‐encapsulation improved peak stress and toughness at high‐strain rates. [ABSTRACT FROM AUTHOR]

This prospective study aimed to compare ultra-high molecular weight polyethylene (UHMWPE) with polyetheretherketone (PEEK) in computer-designed patient-specific implants (PSIs) for cranial defect reconstruction, in terms of complications and aesthetic outcomes. Primary or secondary cranioplasty-eligible patients were included, while patients with active infection or hydrocephalus, or unfit for general anesthesia, were excluded from the study. All the implants were designed and fabricated by the same maxillofacial surgeon using CAD/CAM technology. UHMWPE PSIs were used in group 1 and PEEK PSIs in group 2. Technically, UHMWPE could be milled to a thinner margin thickness than PEEK, which resulted in better handling properties and a smoother end finish. All patients were evaluated over a period of 6 months in terms of overall complications or implant failure as the primary outcome, according to Clavien-Dindo (CVD) grading, and cosmetic satisfaction with the aesthetic results, using a Likert scale, as the secondary outcome. In total, 22 cranioplasty patients were included, with a mean age of 30.8 years (SD = 16.3). Across both groups, 17 patients (77.3%) did not develop postoperative complications. These occurred in three patients in group 1 (CVD grade I, II, and IIIb) (27.3%) and in two patients in group 2 (CVD grade II, IIIa, and IIIb) (18.2%), with no statistical difference (p = 0.6). None of the cases in both groups developed any clinical or radiographic signs of infection, or suffered implant failure. The mean satisfaction score was 4.8 in group 1 and 4.5 in group 2 (SD = 0.6). The difference in satisfaction scores between the two was not statistically significant (p = 0.23). Although UHMWPEE was comparable to PEEK in terms of overall complication rates and cosmesis after craniectomy, UHMWPEE as a material exhibited greater resiliency in technically challenging cases with large, complex/midline-crossing designs, previously fitted meshes, or single-stage resection-reconstruction, allowing better marginal adaptation. [ABSTRACT FROM AUTHOR]

Polymer materials possess low density, high strength, corrosion resistance, and excellent cavitation erosion resistance. As a result, they are widely used in marine, water conservancy, and other engineering equipment as replacements for metal materials. However, polymer friction pairs working in a water environment for an extended period are easily damaged by cavitation erosion. In this work, the cavitation behavior of polytetrafluoroethylene (PTFE) and ultra-high molecular weight polyethylene (UHMWPE) in deionized water and seawater is investigated through experiments and computational fluid dynamics (CFD) simulations. The results indicate that the cavitation erosion resistance of UHMWPE is significantly better than that of PTFE, and the UHMWPE has four cavitation process stages, while the PTFE has only three cavitation stages. 316 L counterparts in the seawater corrosion and cavitation coupling effect of a large number of metal particles off and wash polymer material surface, so that the cavitation erosion of PTFE and UHMWPE is more serious in seawater environment. CFD simulation demonstrates that the cavitation erosion zone under the radiator shows a semicircular distribution. Meanwhile, the formation of ring-shaped cavitation pit is related to the distribution of bubbles on the surface of the radiator. The cavitation rate of PTFE and UHMWPE is slowed down by the "water cushion effect." [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) is known for its exceptional mechanical properties but has relatively insufficient tribological characteristics. This study seeks to enhance its tribological performance without compromising mechanical properties by fabricating PEEK composites incorporating minimal ultra-high-molecular-weight polyethylene (UHMWPE) from 1.0% to 10.0% using hot molding. The hardness, compressive strength, and dry reciprocating friction against bearing steel were evaluated. Results revealed that incorporating just 2.0% UHMWPE into the PEEK matrix significantly reduced the friction coefficient, wear rate, and worn surface roughness by 61%, 89%, and 74%, respectively, compared to pure PEEK, while achieving a notably smooth worn surface. The 2.0% UHMWPE-reinforced PEEK exhibited excellent hardness and compressive strength comparable to pure PEEK, but higher UHMWPE contents decreased these mechanical properties. The UHMWPE proportion of 10.0% resulted in severe adhesive wear, including distinct spalling, plastic deformation, and material accumulation. [ABSTRACT FROM AUTHOR]

This study addresses this issue by exploring the effectiveness of abrasive water jet drilling (AWJD) as an unconventional machining approach for UHMWPE. The research employs a full factorial analysis to examine various hole characteristics, including machining time (MT), surface roughness (Ra), taper angle (TA), material removal rate (MRR), and taper ratio (TR). The study aims to understand the effect of the process features, namely abrasive water jet pressures (p), traverse rates (v), and abrasive mass flow rates (ma), on the geometry and position of the drilled holes. The results show that (v) and (p) affect the drilled hole characteristics of surface morphology, roughness, MT, MRR, TA, and TR. The microstructural characteristics of the drilled-hole surfaces are analyzed by scanning electron microscopy (SEM). It revealed that the smooth surface is attained at the lower v of 150 mm/min and ma of 250 g/min. [ABSTRACT FROM AUTHOR]

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Orthopedics is a science that studies the human body skeleton. This field of science helps patients who experience joint and skeletal problems. One of the problems faced is the need for body frame components to be replaced, for example the knees. This replacement requires a man-made component, namely an implant. Implants can be made from metal, polymer, and ceramic. The biomaterial implant identification process includes X-Ray Diffraction analysis, hardness and tensile testing. XRD testing of CP–Titanium and UHMWPE using the Rigaku XRD tool. CP–Titanium hardness testing uses Vickers micro hardness, while for UHMWPE uses Shore D. CP–Titanium tensile testing uses a universal test machine with JIS Z2201 standards. Another material, namely UHMWPE, is tested using the same equipment as the ASTM D638 standard. The XRD test results for CP - Titanium show peaks of 35.3˚, 38.6˚, 40.2˚, namely the hexagonal structure of the compound element α - Ti. Meanwhile, UHMWPE material shows peaks (110) at 21.66˚ and (200) at 24.16˚. The peak data is an orthorhombic crystal structure, which is characteristic of polyethylene. The CP – Titanium hardness test results show an average hardness of 360.47 VHN. The hardness value of UHMWPE shows an average hardness of 48.5 Shore D. CP - Titanium tensile testing shows a maximum stress value of 534.4 MPa and a maximum strain value of 0.022. The UHMWPE tensile test showed an average maximum stress value of 23.87 MPa and an average maximum strain value of 1.36. The data above shows that the materials tested are CP - Titanium and UHMWPE. Hardness data indicates that these CP – Titanium and polyethylene materials are too soft for applications requiring wear resistance.

Total ankle arthroplasty (TAA) is a motion-preserving treatment for end-stage ankle arthritis. An effective tool for analyzing these implants’ mechanical performance and longevity in silico is finite element analysis (FEA). An FEA in ABAQUS was used to statically analyze the mechanical behavior of the ultra-high-molecular-weight polyethylene (UHMWPE) bearing component at varying dorsiflexion/plantarflexion ankle angles and axial loading conditions during the stance phase of the gait cycle for a single cycle. The von Mises stress and contact pressure were examined on the articulating surface of the bearing component in two newly installed fixed-bearing TAA implants (Wright Medical INBONE II and Exactech Vantage). Six different FEA models of variable ankle compressive load levels and ankle angle positions, for the varying subphases of the stance phase of the gait cycle, were created. The components in these models were constrained to be conducive to the bone–implant interface, where implant loosening occurs. Our results showed that the von Mises stress and contact pressure distributions increased as the compressive load increased. The highest stress was noted at dorsiflexion angles > 15°, in areas where the UHMWPE liner was thinnest, at the edges of the talar and UHMWPE components, and during the terminal stance phase of the gait cycle. This static structural analysis highlighted these failure regions are susceptible to yielding and wear and indicated stress magnitudes that are in agreement (within 25%) with those in previous static structural TAA FEAs. The mechanical wear of the UHMWPE bearing component in TAA can lead to aseptic loosening and peri-implant cyst formation over time, requiring surgical revision. This study provides ankle replacement manufacturers and orthopedic surgeons with a better understanding of the stress response and contact pressure sustained by TAA implants, which is critical to optimizing implant longevity and improving patient care.

The performance of multi‐layer ceramic/composite ballistic armor consisting of Alumina, Carbon fiber, and Ultra High Molecular Weight Polyethylene (UHMWPE) under the impact of 7.62 × 51 M61 caliber armor‐piercing (AP) bullets was examined by experimental and finite element methods. The alumina ceramic thickness used in the experiments is 12 mm. The composite structure thickness used in all samples is 10 mm. Explicit dynamic analyses were also conducted using the Ls‐Dyna to verify the experimental studies. The analysis results were compared with experimental studies and evaluated by considering the damage status of the bullet and armor. According to ballistic test results, partial penetration was observed in all armor produced. The front ceramic layer caused corrosion of the bullet, and a mushrooming effect occurred on it. The carbon fiber layer has dramatically helped as an alternative or support to UHMWPE. Since the results obtained with the carbon fiber ratios used remain within the standards, it will not pose a problem regarding usage. On the contrary, using carbon fiber, which is relatively easier to produce and supply than UHMWPE and more economically suitable, will provide more significant benefits. Experimental and numerical studies have revealed consistent results for all armors. Highlights: The effect of a 7.62 × 51 armor‐piercing bullet on ceramic/composite armor was examined.Carbon fiber and UHMWPE hybrid structure was created in different thicknesses.The carbon fiber layer has dramatically helped as an alternative or support to UHMWPE.Using carbon fiber, which is relatively easier to produce and supply than UHMWPE and is more economically suitable.Experimental and numerical studies have revealed consistent results for all armors. [ABSTRACT FROM AUTHOR]

This paper presents and analyses the numerical results of hypervelocity impact against ultra-high molecular weight polyethylene (UHMWPE) plates with four different surface wave profiles. UHMWPE wavy plates (WP) are intended to be used in Whipple Shield bumper plate, which is of paramount importance for space vehicles against micrometeorite and orbital debris (MMOD) impact protection. Numerical work was carried out as a hybrid combination of smoothed particle hydrodynamics (SPH) and finite element modelling (FEM). Circular plates were subjected to hypervelocity impact of a spherical aluminium projectile travelling at 3000 m/s. The outcomes of the simulations were analysed in terms of debris cloud generation, projectile fragmentation, and impact energy dissipation performance of wavy plates, and compared with a conventional flat counterpart. Results of this study indicate that surface wave profile has a clear positive influence in terms of hypervelocity impact protection performance. [ABSTRACT FROM AUTHOR]

Nowadays, ultra high molecular weight polyethylene (UHMWPE), allows the combination of lightweight, high strength and is praised for the design of severely loaded structures. It has become a good option for lightweight armour solutions. It is therefore important to characterise its mechanical behaviour. Up to now, strain rate effects on mechanical behaviour have been poorly explored. In this work, this issue is tackled by studying the strain rate influence on the in-plane deformation, in shear and tension of the Tensylon® HSBD30A, a UHMWPE dedicated to ballistic and blast protection. Two laminates of Tensylon® of respective orientation [0 °/90°]20 and [±45°]20 were subjected to static and split Hopkinson tensile bar (SHTB) tests. A new mounting system was designed, and new specimen shapes were used to match the experimental setup configurations. Digital image correlation (DIC) was used to measure the in-plane strain. A significant strain-rate dependence on the material behaviour.is evidenced. Besides, results exhibit a higher strength for the [0°/90°]20 specimen than for the [±45°]20 one. Despite some limitations, the proposed setup and measurement methods allowed visualisation of strain rate effects on the stress-strain relationship for strain rates ranging from the quasi-static regime to the dynamic one (1500 s–1). [ABSTRACT FROM AUTHOR]

Copyright of Advanced Textile Technology is the property of Zhejiang Sci-Tech University Magazines and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Industria Textila is the property of Institutul National de Cercetare-Dezvoltare pentru Textile si Pielarie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Total ankle arthroplasty (TAA) is a motion-preserving treatment for end-stage ankle arthritis. An effective tool for analyzing these implants' mechanical performance and longevity in silico is finite element analysis (FEA). An FEA in ABAQUS was used to statically analyze the mechanical behavior of the ultra-high-molecular-weight polyethylene (UHMWPE) bearing component at varying dorsiflexion/plantarflexion ankle angles and axial loading conditions during the stance phase of the gait cycle for a single cycle. The von Mises stress and contact pressure were examined on the articulating surface of the bearing component in two newly installed fixed-bearing TAA implants (Wright Medical INBONE II and Exactech Vantage). Six different FEA models of variable ankle compressive load levels and ankle angle positions, for the varying subphases of the stance phase of the gait cycle, were created. The components in these models were constrained to be conducive to the bone–implant interface, where implant loosening occurs. Our results showed that the von Mises stress and contact pressure distributions increased as the compressive load increased. The highest stress was noted at dorsiflexion angles > 15°, in areas where the UHMWPE liner was thinnest, at the edges of the talar and UHMWPE components, and during the terminal stance phase of the gait cycle. This static structural analysis highlighted these failure regions are susceptible to yielding and wear and indicated stress magnitudes that are in agreement (within 25%) with those in previous static structural TAA FEAs. The mechanical wear of the UHMWPE bearing component in TAA can lead to aseptic loosening and peri-implant cyst formation over time, requiring surgical revision. This study provides ankle replacement manufacturers and orthopedic surgeons with a better understanding of the stress response and contact pressure sustained by TAA implants, which is critical to optimizing implant longevity and improving patient care. [ABSTRACT FROM AUTHOR]

To address the issues of abrasive wear, impact wear, and soil adhesion that can lead to wear failure and excessive operational resistance in agricultural soil touching parts during farming. This study focuses on UHMWPE composites, modified by filling Nano‐SiC as a hard phase filler and XNBR as an elastic filler. These fillers were dispersed into the UHMWPE matrix through melt blending technology to create a high‐performance composite material for the surface protective material of soil touching parts. The study discovered that by adding hard and elastic fillers to the UHMWPE matrix, the density, hardness, flexural modulus and thermal stability of the materials were all increased. Specifically, the density increased by 5.67% and the flexural modulus increased by 107%. In the block on ring wear test the volumetric wear rate decreased by 98%, while in the mortar wear test the mass wear rate decreased by 64.64%. Additionally, the contact angle on the surface of the specimen after mortar erosion and wear increased to 102.76°, 18% higher than that of pure UHMWPE. These results demonstrate that the modified fillers can improve the abrasion and plastic deformation resistance and hydrophobic desorption of UHMWPE. UHMWPE composite material, serving as the surface protection for soil touching parts, resolves the issues of abrasion of soil abrasive particles and excessive soil adhesion resistance on these parts. This significantly prolongs the service life of soil touching parts of agricultural machinery and improves the operational efficiency and economy. Highlights: Research on nanoparticles and elastomer‐modified composite materials.Research has shown the enhancement of UHMWPE composite materials by Nano‐SiC.XNBR improves the plastic deformation resistance of UHMWPE composites.Effects of Nano‐SiC and XNBR on the desorption behavior of composite materials.UHMWPE composites reduce soil contact wear and soil adhesion. [ABSTRACT FROM AUTHOR]

The increasing awareness of safety standards for personal protective equipment in various industries and everyday life has significantly increased the demand for effective cut‐resistance clothing to prevent injuries. Ultra‐high molecular weight polyethylene (UHMWPE), renowned for its strength, is predominantly used to produce cut‐protective clothing for sectors such as automotive, manufacturing, glass, and metal. These cut‐resistance clothing are often exposed to harsh workplace conditions, including elevated temperatures, which can compromise their structural integrity and diminish their cut‐protection efficacy. The present work investigates the effect of temperature on the cut‐resistance performance of core‐spun UHMWPE yarns integrated with stainless‐steel and glass filament‐based knitted fabrics. Cut‐performance was assessed across industrial work handling temperatures ranging from 30 to 75°C. Furthermore, thermal cut performance was analyzed by structural characterization and surface morphology of the samples. The results revealed a general decline in cut performance with increasing temperature for all samples, with stainless steel‐reinforced UHMWPE fabrics experiencing the most pronounced reduction % compared with their glass fiber‐reinforced and 100% UHMWPE counterparts. These results are substantiated by analyses of surface temperature distribution profiles and x‐ray diffraction outcomes. This study benefits industry workers, guiding them in selecting effective protective clothing for varied thermal conditions. [ABSTRACT FROM AUTHOR]

UHMWPE nascent powders have been commercially processed by sintering for decades although key aspects of the mechanisms and kinetics of this process are not fully understood. Herein, the volume change during each stage of the sintering is monitored by in‐situ measurements with other characterization methods. Results indicate that the α‐transition plays a crucial role in the early stages of the sintering process. Without pressure during sintering, a large expansion is observed during heating through the α‐transition well before melting and this apparent volume change is also related to the residual stress resulting from the compaction. However, the application of a moderate pressure during heating leads to a significant densification. Specifically, five distinct processes are identified from the in‐situ measurements via customized pressure sintering apparatus. These include room temperature densification, subsequent densification while heating through the α‐transition, process of melt explosion that involves the enthalpic process of crystal melting and the entropic process density changes during the isothermal sintering of non‐equilibrium melt, and the subsequent recrystallization under pressure. The density evolution offers a comprehensive understanding of the intricate processing of UHMWPE nascent powder and this can be effectively employed to investigate the impact of various processing parameters on the sintering process. [ABSTRACT FROM AUTHOR]

The development of ultra-high molecular weight polyethylene fibers has resulted in continued improvement in ballistic protection, along with reduced weight in body armors. Prepregs from newly developed fibers are constantly available, although prepregs from older brands still remain on the market. In this work, the physicochemical properties of two successive generations of pre-impregnated materials are characterized to compare the two materials in the as-received condition and also after be consolidated in a ballistic plate. The results showed that fibers from the newer brand have a smaller diameter and greater tensile strength. This is an important result because the tensile strength of fibers is one of the variables that influence the ballistic performance of body armors. The smaller diameter of these fibers was associated with a greater degree of stretching during their manufacture, as revealed by the presence of two melting peaks in the DSC analysis. [ABSTRACT FROM AUTHOR]

As the risk of social security increases, it is crucial to develop flexible protective materials that combine flexibility with high protective performance. Ultra-high-molecular-weight polyethylene (UHMWPE) was selected as the raw material, and four types of flat-knitting cut-resistant fabrics were ultimately designed and prepared from a three-dimensional longitudinal dimension and concave–convex array structure based on rib knitting. A series of experiments must be conducted on fabrics in order to study the law of protection performance of different structural fabrics. They were thus subjected to comprehensive evaluation and theoretical analysis of cut resistance. The results demonstrate that the four structural fabrics exhibited resilience in abrasion tests, withstanding over 100,000 cycles without failure. A weighting algorithm was employed to determine the comprehensive cutting resistance of the S1, S2, S3, and S4 structural fabrics, resulting in values of 1939.9 gf, 2298.6 gf, 2577.1 gf, and 2822.2 gf, respectively. Therefore, S1 reached class A4, which is sufficient to address a medium cut hazard. Similarly, S2, S3, and S4 reached class A5, which is adequate to address a high cut hazard. The obtained fitting equation, with uniform yarn fineness T as the dependent variable, demonstrates that the cut resistance improved as the concave–convex density level increased. [ABSTRACT FROM AUTHOR]

Simple Summary: Rupture of the cranial cruciate ligament (CrCL) is a common condition in dogs, causing instability of the stifle, pain, lameness, osteoarthritis, and meniscal tears. Common treatments consist of tibial osteotomies or extra-articular stabilization of the stifle according to the size and weight of the dog. The most marginal routine practice is intra-articular stabilization, which consists of replacing the ruptured CrCL with an organic graft or a synthetic implant. This case report describes the technique used for the intra-articular synthetic reconstruction of the CrCL under arthroscopic guidance in a dog. This report is supported by a six-month clinical outcome assessment consisting of orthopedic examinations and radiographs. The dog showed quick resumption to normal gait and standing posture with no worsening of osteoarthritis and synovial effusion or complications. Mild signs of stifle instability were observed with no impact on clinical outcome. This technique could be considered an alternative for the treatment of CrCL rupture in dogs, but it needs confirmation from additional clinical studies with more dogs. The intra-articular reconstruction of the cranial cruciate ligament (CrCL) by an organic graft or a synthetic implant allows the restoration of physiological stifle stability. This treatment is still marginal in routine practice. A Rottweiler presented an acute complete CrCL rupture treated using an ultra-high-molecular-weight polyethylene (UHMWPE) implant. The latter was positioned under arthroscopic guidance and fixed with interference screws through femoral and tibial bone tunnels. The dog was weight-bearing just after surgery and resumed normal standing posture and gait after one month, with mild signs of pain upon stifle manipulation. At three months postoperatively, minimal muscle atrophy and minimal craniocaudal translation were noted on the operated hindlimb, with no effects on the clinical outcome. The stifle was painless. At six months postoperatively, standing posture and gait were normal, muscle atrophy had decreased, the stifle was painless, and the craniocaudal translation was stable. On radiographs, congruent articular surfaces were observed without worsening of osteoarthrosis over the follow-up, as well as stable moderate joint effusion. Replacement of a ruptured CrCL with a UHMWPE ligament yielded good functional clinical outcome at six months postoperatively. This technique could be considered an alternative for the treatment of CrCL rupture in large dogs, but it needs confirmation from a prospective study with more dogs. [ABSTRACT FROM AUTHOR]

This study demonstrates the development of a unique hybrid thermoplastic composite using reduced Graphene oxide (rGO) content and Zirconia (ZrO2) nanoparticles into the Ultra-High Molecular Weight Polyethylene (UHMWPE) biomaterials for continuous loading conditions. Specimens with different loadings of rGO (0 to 1.5 wt.%) and ZrO2 (5 to 10 wt.%) were fabricated using liquid phase ultrasonication followed by the hot press moulding method. The samples were analyzed using Thermogravimetric Analysis (TGA), Impact (Izod) testing, and Dynamic Mechanical Analysis (DMA). The developed material feasibility was assessed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analyses. The findings revealed that the 1 wt.% rGO/5 wt.% ZrO2/UHMWPE sample improved the storage modulus by 66.15%, and the Impact absorbed energy by 11.33% compared to the pristine UHMWPE. The proposed nanocomposite could be endorsed for artificial joints, prostheses, and other Artificial Bio-Bearing (ABB) applications.

To enhance the ballistic impact performance and impart electrical conductivity into soft armor material made up of UHMWPE fabric, a novel hybrid technique has been devised and incorporated. Initially, the NiP layer was deposited on the UHMWPE fabric surface through the electroless process, subsequently, it was impregnated in the shear thickening fluid (STF) based on nano-silica (40 wt%). The morphology, functional groups, phase structure, thermal stability, breaking load, inter-yarn friction, electro-heating, and ballistic impact performance of the neat (UHM), STF impregnated (UHM-STF), NiP coated(UHM/NiP), and NiP coated STF impregnated (UHM/NiP-STF) fabrics are detailed. The NiP coating enhanced the ballistic impact performance, and thermal stability, and became electrically conductive compared to neat fabric. The ballistic impact test confirmed the enhancement in the energy absorption of UHM-STF (30.84%), UHM/NiP(18.37%), and UHM/NiP-STF(54.82%) compared to UHM. The hybrid technique (UHM/NiP-STF) exhibited higher inter-yarn friction (53.79%) and ballistic impact energy absorption (18.43%) compared to UHM-STF. The significant rise in the impact energy absorption of the UHM/NiP-STF can be ascribed to the synergetic effect of enhanced inter-yarn friction induced by the NiP-coated layer and the shear thickening behavior exhibited by STF. The NiP-coated and STF-impregnated fabrics present a promising prospect for the advancement of soft body armor materials with multifunctional ability.

The high strain-rate and temperature properties of ultra-high molecular weight polyethylene (UHMWPE) composites are limitedly available in the public domain, primarily due to challenges in gripping the extremely strong material during testing. In this study, tensile tests were performed on UHMWPE laminates over a range of strain-rates from 4.00 × 10-4 to 2.45 × 102 s-1, and at different temperatures from -10 to 70 °C using an innovative interchangeable clamping system. The clamp was designed to overcome gripping issues while ensuring consistent boundary conditions across various testing devices. Digital Image Correlation (DIC) technique was employed to capture the displacement fields in situ. The results show that UHMWPE composites demonstrate strain-rate strengthening and temperature-induced softening effects. The strain-rate dependent models indicate a notable difference in strain-rate sensitivity, particularly with tensile strength exhibiting 87 % and 60 % higher sensitivity compared to the tensile modulus and failure strain, respectively. The Weibull statistical model indicates that the scale parameter increases by 17 % with the increase in strain-rate due to transition in failure response from ductile to brittle, which is observed through optical microscopy. In contrast, the scale parameter decreases by 58 % with the increase in temperature. Therefore, it is important to consider the effects of strain-rate and temperature on the mechanical properties for effectively utilizing this material to develop numerical models in various impact-protective applications.

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PURPOSE OF STUDY Total joint replacements (TJR) have become the cornerstone of modern orthopedic surgery. A great majority of TJR employs ultrahigh molecular weight polyethylene (UHMWPE) liners. TJR manufacturers use many different types of UHMWPE, which are modified by various combinations of crosslinking, thermal treatment, sterilization and/or addition of biocompatible stabilizers. The UHMWPE modifications are expected to improve the polymer’s resistance to oxidative degradation and wear (release of microparticles from the polymer surface). This manuscript provides an objective, non-commercial comparison of current UHMWPE formulations currently employed in total knee replacements. MATERIALS AND METHODS UHMWPE liners from 21 total knee replacements (TKR) were collected which represent the most implanted liners in the Czech Republic in the period 2020–2021. The UHMWPEs were characterized using several methods: infrared microspectroscopy (IR), non-instrumented and instrumented microindentation hardness testing (MH and MHI), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and solubility measurements. The above-listed methods yielded quite complete information about the structure and properties of each UHMWPE type, including its potential long-term oxidation resistance. RESULTS For each UHMWPE liner, IR yielded information about immediate oxidative degradation (in the form of oxidation index, OI), level of crosslinking (trans-vinylene index, VI) and crystallinity (CI). The MH and MHI testing gave information about the impact of structure changes on mechanical properties. The remaining methods (DSC, TGA, and solubility measurements) provided additional information regarding the structure changes and resistance to long-term oxidative degradation. Statistical evaluation showed significant differences among the samples as well as interesting correlations among the UHMWPE modifications, structural changes, and mechanical performance. DISCUSSION Surprisingly enough, UHMWPE materials from different manufacturers showed quite different properties, including the resistance against the long-term oxidative degradation, which is regarded as one of the main reasons of TJR failures. The most promising UHMWPE types were crosslinked materials with biocompatible stabilizers. CONCLUSIONS Current UHMWPE liners from different manufactures used in total knee replacements exhibit significantly different structure and properties. From the point of view of clinical practice, the traditional UHMWPE types, which contained residual radicals from irradiation and/or gamma sterilization, showed inferior resistance to oxidative degradation and should be avoided. The best properties were observed in modern UHMWPE types, which combined crosslinking, biocompatible stabilizers, and sterilization by ethylenoxide or gas plasma. [ABSTRACT FROM AUTHOR]

The cavitation process of high‐performance HDPE/UHMWPE blends with a uniform dispersion of UHMWPE during cold stretching was investigated. It was observed that incorporating a small amount of UHMWPE into the HDPE matrix resin can serve as a nucleating agent, increasing the number of contact sites and accelerating the crystallization rate. This leads to the formation of thicker lamellar crystals and tethered molecules, ultimately enhancing the mechanical properties of the HDPE matrix. Furthermore, the relationship between the natural tensile ratio and strain‐hardening modulus was confirmed. Microstructural changes within the blends were also explored. As the drawing tangles in the middle, the cavities subsequently evolve by collapsing and merging to align parallel to the tensile direction, culminating in tensile damage forming a large crack in the final macroscopic form. As a result, the presence of more tethered molecules in the later stages of stretching inhibits further cavity growth. Highlights: The HDPE/UHMWPE blends were prepared by solution blending and ultrasound‐assisted twin‐screw extrusion.The mechanisms underlying the formation and evolution of cavities in HDPE/UHMWPE blends, which lead to stress whitening during tensile damage, were examined by using DSC and SAXS/WAXD.The relationship between microstructure and mechanical properties was analyzed by cold‐drawing the molded blended sheets at room temperature. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this cross‐sectional study was to compare survival, clinical and radiographic results of total knee arthroplasty (TKA) with vitamin E‐stabilized polyethylene (VEPE) or conventional polyethylene (CPE) at a minimum of 7‐year follow‐up. Methods: Patients who underwent primary TKA between 2011 and 2015, receiving the same cemented rotating platform knee design with VEPE or CPE tibial inserts, were identified. Patients were contacted for clinical and radiographic follow‐up. American Knee Society Score (KSS), Forgotten Joint Score (FJS‐12), presence of periprosthetic radiolucent lines (RLLs) and osteolysis were evaluated at the last follow‐up. Any revision, reintervention or other complications were recorded. Results: Among 350 TKAs initially identified, 102 VEPE and 97 CPE knees were included for analysis with mean follow‐up of 8.5 and 8.3 years, respectively. No significant difference was found in survival rates at 10‐year follow‐up with revision due to aseptic loosening (95.0% vs. 97.8%, p = 0.29) or due to any reason (87.6% vs. 89.6%, p = 0.78) between VEPE and CPE TKA. KSS function score resulted significantly higher in the VEPE group over CPE (77 vs. 63, p = 0.01). RLLs were more frequent in VEPE than CPE (54% vs. 32%, p = 0.05), mainly noticed medially and posteriorly beneath the tibial plate, adjacent to the trochlear shield and the posterior condyles. Osteolysis was observed in one knee per group, but patients were asymptomatic with stable implants. Conclusion: TKA with VEPE and CPE tibial inserts showed comparable survival rates, complications and clinical and radiographic results up to 10‐year follow‐up. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

The study of wear is currently one of the most important aspects of applied mechanics. The damage caused by this phenomenon involves the total replacement of parts in devices ranging from industrial machinery to biomedical implants. The focus of these work is aimed at the analysis and prediction of mechanical wear in prostheses manufactured using UHMWPE materials and 316 LVM stainless steel by means of the finite element method using Abaqus® software V. 2020. The wear mechanism between the surfaces of the UHMWPE material specimen and a 316 LVM stainless steel specimen was modeled using Archard's wear theory to determine the parameters of damage, plastic deformation, and fatigue. The attrition process was discretized into several steps, including developing a program in Fortran code, and integrating a pre-established subroutine known as UMESHMOTION, followed by a Mesh update whenever contact nodes were deformed. For the simulation process, the variables of the thermal properties of conductivity, specific heat, and the parameters of the Johnson-Cook plastic model were taken into account. The simulation results were validated by laboratory tests. [ABSTRACT FROM AUTHOR]

Ultra-high molecular-weight polyethylene (UHMWPE) is one of the most extensively utilized supporting materials inside total knee replacement (TKR) because of its combination of outstanding mechanical qualities and wear resistance. The integrity of the hole is an essential component for fastening the femur and tibia elements in knee replacements. Due to its viscoelasticity behavior, it often causes difficulties such as rapid tool wear, burr formation, and poor finish in conventional machining operations, which causes poor hole features. Since unconventional methods are currently being investigated for drilling UHMWPE. Abrasive water jet drilling (AWJD) is particularly promising for handling hard-to-machine materials, and AWJ drilling of UHMWPE materials demands focus on it. The focus of this research is to determine the importance of AWJD variables for UHMWPE. In this experiment, 64 holes, each with a diameter of 10mm, were drilled into the sample material using a complete factorial approach to evaluation. Abrasive water jet pressure (AWJP) (210, 260, 310, and 360MPa), abrasive mass flow rate (AMFR) (250, 300, 350, and 400g/min.), and traverse rate (TR) (150, 300, 450, and 600mm/min.) were all taken into account. Furthermore, the geometrical properties of the hole, such as hole diameter (entry and exit), circularity, perpendicularity, and cylindricity, were investigated. The outcomes identified that both AWJP and TR played significant roles in determining the geometric features of the hole. During the drilling operation, the material removal mechanism and the hole defects were observed and identified using scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

A hybrid of halloysite nanotubes decorated with titanium dioxide nanoparticles (HNTs@TiO2) was synthesized by the sol–gel method and then mixed with ultra‐high molecular polyethylene (UHMWPE) by melt compounding to enhance its wear resistance properties. The incorporation of HNTs@TiO2 increased the crystallinity as well as the hardness of UHMWPE nanocomposites, which benefited less prone to plastic deformation during the friction process. In addition, the UHMWPE/HNTs@TiO2 maintained a high ductility character with a slight decrease in tensile strength compared to pure UHMWPE. With the addition of 3 wt% HNTs@TiO2, the UHMWPE nanocomposite achieved a remarkably low friction coefficient of 0.073 and a reduced wear rate of 6.67 × 10−6 mm3/N·m. These values represented a 32.4% decrease in friction coefficient and a 43.9% decrease in wear rate compared to pure UHMWPE. The improvement in wear resistance was due to the dislodged TiO2 and HNTs had good synergistic rolling effects at the counterface. Furthermore, the wear scan morphology observation revealed that the transferred HNTs@TiO2‐based materials could help to improve the quality of the tribofilms, which alleviated the abrasive wear from the metallic counterpart. This work offers a feasible way to enhance the wear resistance of UHMWPE nanocomposite without sacrificing the high ductility for expanding its engineering applications. Highlights: TiO2‐decorated halloysite nanotubes were synthesized by the sol–gel method.The addition of HNTs@TiO2 maintained the high ductility character of UHMWPE.The UHMWPE composite with 3 wt% HNTs@TiO2 had the best wear resistance. [ABSTRACT FROM AUTHOR]

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