Poly wear

Osteoarthritis is caused by degeneration of the cartilage, which covers the bone ends of the joints and is decorated with an oligolamellar phospholipid (PL) bilayer. The gap between the bone ends is filled with synovial fluid mainly containing hyaluronic acid (HA). HA and PLs are supposed to reduce friction and protect the cartilage from wear in joint movement. However, a detailed understanding of the molecular mechanisms of joint lubrication is still missing. Previously, we found that aqueous solutions of HA and poly(allylamine hydrochloride) (PAH), the latter serving as a polymeric analogue to HA, adsorb onto the headgroups of surface-bound 1,2-dimyristoyl- sn -glycero-3-phosphocholine (DMPC) oligobilayers and significantly enhance their stability with respect to shear forces, typically occurring in joint movement...

Poly(bis(2-ethylhexyl) phosphoric) methacrylic anhydride-grafted carbon dots (CD- g -PEPMA) have been controllably synthesized and used as multifunctional lubricant additives of poly(ethylene glycol) (PEG200). The polymers on the surfaces of CD- g -PEPMA not only endow them with particularly excellent dispersion stability but also enhance their adsorbability on the steel surface and embedded stability between the rubbing surfaces. Hence, CD- g -PEPMA as an additive showed outstanding rust resistance and tribological performance...

This study aims to investigate the influence of graphene nanoplatelet (GNP) concentration on the electrochemical and tribological properties of GNP-poly(methyl methacrylate) (PMMA) composite coatings. GNP-PMMA coatings were prepared with varying GNP concentrations (0.5, 1.0, 3.0, and 5.0 wt %) using the drop-casting method onto AA6061 aluminum alloy substrates. Results showed that the addition of 1.0 wt % GNP increased the tensile strength of PMMA but further increase reduced the tensile strength and fracture strain of the composites...

CASE: A 58-year-old woman presented with swelling, stiffness, and pain of the right knee 28 years after rotating-hinge distal femoral replacement after osteosarcoma resection. She underwent revision. There was wear through the entire thickness of the polyethylene tibial sleeve bushing, and the implant was well-fixed. The knee was reassembled with new bushings, sleeves, yoke, axle, poly, and a locking pin. CONCLUSION: This is the first described case of tibial sleeve bushing wear...

Stormwater has been identified as a pathway for microplastics (MPs), including tire wear particles (TWPs), into aquatic habitats. Our knowledge of the abundance of MPs in urban stormwater and potential strategies to control MPs in stormwater is still limited. In this study, stormwater samples were collected from microlitter capture devices (inlet and outlet) during rain events. Sediment samples were collected from the material captured in the device and from the inlet and outlet of a constructed stormwater wetland...

During the COVID-19 pandemic, the use of face masks has been a worldwide primary protection measure to contain the spread of the virus. However, very little information is known about the possible inhalation of microplastics (MP) from wearing masks. This pilot study evaluates the presence of MP accumulated in nasal cavities through the nasal lavages technique. Six different commercial face masks were tested in 18 participants during five working days (8 h use/day). Eight different polymers (polystyrene, polyamide, poly(ethylene - propylene) diene monomer, polyester, polyethylene, polyvinylidene fluoride, polypropylene, and polyvinyl chloride) predominantly within the 20-300 µm size were detected in nasal lavages, with an average concentration of 28...

PURPOSE: The aim of this study was to evaluate the surface wear and retention force of telescopic attachments made of zirconia primary crowns and poly-ether- ketone -ketone (PEKK) secondary crowns for 2-implant retained mandibular complete overdentures. MATERIALS AND METHODS: Ten healthy completely edentulous patients aged 55-60 years were selected for this study. Each patient received two implants in the mandibular canine regions. Maxillary conventional complete dentures were constructed against implant-retained mandibular overdentures for all patients...

BACKGROUND: The aim of this study was to establish a sheep model of the Puricelli biconvex arthroplasty (ABiP) technique in sheep for evaluating its functional, biological and histological parameters. METHODS: Ten Corriedale black sheep were submitted to TMJ total reconstruction with poly(methyl methacrylate) (PMMA) using ABiP and euthanized after 45 (n = 5) or 90 (n = 5) days. Control animals (n = 2) underwent sham operations and were euthanized after 45 days...

This manuscript presents an experimental investigation of the friction and wear properties of poly (methyl methacrylate) (PMMA) nanocomposites reinforced with functionalized multi-walled carbon nanotubes (MWCNTs). The aim of this study is to evaluate the potential of MWCNTs as a reinforcement material for enhancing the tribological performance of PMMA. Three types of multi-walled carbon nanotubes, i.e., pristine, hydroxyl functionalized, and carboxyl functionalized, were utilized in this study. The nanocomposite samples were prepared by dispersing varying concentrations of MWCNTs (0...

This study investigated the mechanical and tribological properties of 3D-printed Poly (lactic acid) (PLA) composites reinforced with different concentrations of carbon fibers (SCF) and graphene nanoparticles (GNP) (0.5 to 5 wt.% of each filler). The samples were produced using FFF (fused filament fabrication) 3D printing. The results showed a good dispersion of the fillers in the composites. SCF and GNP promoted the crystallization of the PLA filaments. The hardness, elastic modulus, and specific wear resistance grew with the increase in the filler concentration...

The absence of artificial articular cartilage could cause the failure of artificial joints due to excessive material wear. There has been limited research on alternative materials for articular cartilage in joint prostheses, with few reducing the friction coefficient of artificial cartilage prostheses to the range of the natural cartilage friction coefficient (0.001-0.03). This work aimed to obtain and characterize mechanically and tribologically a new gel for potential application in articular replacement...

Particulate matter (PM2.5 ) samples were collected at two different places of a college campus (CC) and a bus stop (BS) nearby the college campus. The traffic volume of college campus was very low due to untact classes. Polymeric components and tire wear particle (TWP) contents in the PM2.5 samples were analyzed using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Various polymeric components such as natural rubber (NR), bitumen, saturated hydrocarbons, poly(ethylene terephthalate) (PET), and plant-related particles (PRPs) were observed...

In recent years, flexible strain sensors have attracted increasing interest, and accurate sensing and comfortable wearables are highly demanded. However, current flexible strain sensors fail to have wide linearity and high sensitivity simultaneously, and their adhesion is insufficient for convenient wear and precise motion monitoring. Herein, chitosan/poly(vinyl alcohol) hydrogels with phytic acid (PA) and boric acid (BA) as crosslinkers (CS/PVA-PA-BA hydrogels) were fabricated. The synergy of phytic acid and boric acid not only improved the mechanical properties of the obtained hydrogels (1070% of fracture strain and 0...

PURPOSE: This study aimed to synthesize heat-cured poly(methyl methacrylate) (PMMA) acrylic formulated with copper nanoparticles (nCu) for producing dentures with antimicrobial properties and ability to prevent denture stomatitis (DS). METHODS: nCu/PMMA nanocomposites were prepared through in situ formation of nCu into methyl methacrylate (MMA). The fabricated material was characterized using scanning electron microscopy, spectroscopy (energy-dispersive X-ray, attenuated total reflectance-Fourier-transform infrared, and X-ray photoelectron spectroscopy), X-ray diffraction analysis, and mechanical flexural tests (ISO 20795-1:2008)...

Fused deposition modeling (FDM) processed Poly-ether-ether-ketone (PEEK) materials are widely used in aerospace, automobile, biomedical, and electronics industries and other industries due to their excellent mechanical properties, thermal properties, chemical resistance, wear resistance, and biocompatibility, etc. However, the manufacture of PEEK materials and parts utilizing the FDM process faces the challenge of fine-tuning a list of process parameters and heat treatment conditions to reach the best-suiting mechanical properties and microstructures...

Although microplastics (MPs) are intrinsically toxic and function as vectors for organic micropollutants, their discharge from wastewater treatment plant effluents and human activity remains unknown owing to the limitations of detection and treatment technologies. It is imperative to quantify MPs from human activities involving the consumption of various plastic products. This study warns that contact lenses can generate MPs and nanoplastics (NPs) after being discharged into aquatic environments. Identification via micro-Fourier transform infrared spectroscopy revealed that the fragmented particles (from a few tens to a few hundred micrometres) could not be detected as poly(2-hydroxyl methacrylate), the component of contact lenses, owing to changes in its chemical properties...

This paper demonstrates the hybridization of copolymer microgel with drug-loaded metal-organic frameworks nanoparticles that can achieve excellent aqueous lubricating performance and anti-inflammatory effect for synergistic treatment of osteoarthritis (OA). Poly(ethylene glycol)-graft-poly(N-isopropylacrylamide) (PEG-g-PNIPAm) microgel layer is grown on the MIL-101(Cr) surface via one-pot soap-free emulsion polymerization method. The lower critical solution temperature of the MIL-101(Cr)@PEG-g-PNIPAm hybrid is raised significantly by incorporating PEG chains into the PNIPAm microgel matrix, which greatly enhances the high-temperature aqueous dispersion stability...

Traditional conductive fabrics are prepared by the synthesis of conductive polymers and the coating modification of metals or carbon black conductive materials. However, the conductive fabrics cause a significant decline in performance after washing or mechanical wear, which limits their application. Moreover, the single function of the traditional conductive fabric is also the reason that limits its wide application. In order to prepare a wearable, stable, high-performance, washable, multifunctional conductive fabric, we have carried out related research...

A superhydrophobic (SH) surface is typically constructed by combining a low-surface-energy substance and a high-roughness microstructure. Although these surfaces have attracted considerable attention for their potential applications in oil/water separation, self-cleaning, and anti-icing devices, fabricating an environmentally friendly superhydrophobic surface that is durable, highly transparent, and mechanically robust is still challenging. Herein, we report a facile painting method to fabricate a new micro/nanostructure containing ethylenediaminetetraacetic acid/poly(dimethylsiloxane)/fluorinated SiO2 (EDTA/PDMS/F-SiO2 ) coatings on the surface of a textile with two different sizes of SiO2 particles, which have high transmittance (>90%) and mechanical robustness...

Nano-crystalline diamond has been extensively researched and applied in the fields of tribology, optics, quantum information and biomedicine. In virtue of its hardness, the highest in natural materials, diamond outperforms the other materials in terms of wear resistance. Compared to traditional single-crystalline and poly-crystalline diamonds, nano-crystalline diamond consists of disordered grains and thus possesses good toughness and self-sharpening. These merits render nano-crystalline diamonds to have great potential in tribology...