“…However, exact mechanisms regarding UHMWPE adhesion is still under study 27 , whereas tribological contact represents yet additional influential factor. In another study, thin layer of PMMA deposited on the UHMWPE produced COF values of 0.12–0.16 (for 6–10 N load range) and 0.18–0.22 (for lower load range of 2–4 N) 28 , what is in consistence with our results (Figure 3).…”
Section: Resultssupporting
confidence: 91%
“…However, tribological contact in chemically aggressive environment can affect its chemical reactions, due to the changes in UHMWPE wettability and mechanical interlocking in surface layers. Hence, under some conditions, UHMWPE can react with PMMA 27–29 , meaning that it can form thin PMMA layers within nano and micro surface regions during the tribological contact that might be responsible for the further changes in frictional response during one test. Physico-chemical mechanisms (intermolecular interactions, chemical bonding, physical adhesion) or mechanical interlocking during the micro and nano contacts, due to the surface roughness shapes (crevices, pits, valleys and similar) both promote adhesion on the UHMWPE surface, especially at micro scale 27 .…”
Dynamic friction coefficient (COF) of the reciprocating sliding contact of the conventional UHMWPE, was investigated in four different environments (dry contact; distilled water; pure Ringer's solution and with PMMA particles), at five values of low normal load (0.1–1 N) and three values of sliding speed (4 - 12 mm/s). Significant differences of COF values occurred at the lowest load (0.1 N), whereas sliding speed did not influence COF values. Addition of PMMA particles in Ringer's solution produced significant increase of COF values, especially at the lowest load of 0.1 N. For the dry contact and the highest load (1 N), steady state was reached shortly after the beginning of the test and friction coefficient had uniform behaviour. In the case of wet environment and the lowest load, steady state was not reached and the friction coefficient exhibited non-reproducible random behaviour. According to the Hertz theory, 0.5 N load corresponded to the elastic stress of 48.7 MPa, thus surpassing the values of the elastic limits, hardness and true yield stress of the UHMWPE, and the behaviour of the friction coefficient was drastically different below and above this load value. It can be assumed that below the 0.5 N load, viscoelastic response, accompanied with plastic deformation is dominant, with transition to mainly plastic deformation for the higher loads.
“…However, exact mechanisms regarding UHMWPE adhesion is still under study 27 , whereas tribological contact represents yet additional influential factor. In another study, thin layer of PMMA deposited on the UHMWPE produced COF values of 0.12–0.16 (for 6–10 N load range) and 0.18–0.22 (for lower load range of 2–4 N) 28 , what is in consistence with our results (Figure 3).…”
Section: Resultssupporting
confidence: 91%
“…However, tribological contact in chemically aggressive environment can affect its chemical reactions, due to the changes in UHMWPE wettability and mechanical interlocking in surface layers. Hence, under some conditions, UHMWPE can react with PMMA 27–29 , meaning that it can form thin PMMA layers within nano and micro surface regions during the tribological contact that might be responsible for the further changes in frictional response during one test. Physico-chemical mechanisms (intermolecular interactions, chemical bonding, physical adhesion) or mechanical interlocking during the micro and nano contacts, due to the surface roughness shapes (crevices, pits, valleys and similar) both promote adhesion on the UHMWPE surface, especially at micro scale 27 .…”
Dynamic friction coefficient (COF) of the reciprocating sliding contact of the conventional UHMWPE, was investigated in four different environments (dry contact; distilled water; pure Ringer's solution and with PMMA particles), at five values of low normal load (0.1–1 N) and three values of sliding speed (4 - 12 mm/s). Significant differences of COF values occurred at the lowest load (0.1 N), whereas sliding speed did not influence COF values. Addition of PMMA particles in Ringer's solution produced significant increase of COF values, especially at the lowest load of 0.1 N. For the dry contact and the highest load (1 N), steady state was reached shortly after the beginning of the test and friction coefficient had uniform behaviour. In the case of wet environment and the lowest load, steady state was not reached and the friction coefficient exhibited non-reproducible random behaviour. According to the Hertz theory, 0.5 N load corresponded to the elastic stress of 48.7 MPa, thus surpassing the values of the elastic limits, hardness and true yield stress of the UHMWPE, and the behaviour of the friction coefficient was drastically different below and above this load value. It can be assumed that below the 0.5 N load, viscoelastic response, accompanied with plastic deformation is dominant, with transition to mainly plastic deformation for the higher loads.
“…The percent decrease in the wear rate of the composites concerning its matrix varies from system to system depending upon the particle morphology of the fillers and other experimental conditions. A 5.5% and 35.2% decrease in the wear rate was observed at 2 and 8 N, respectively, for C m C for the PMMA matrix in a dry condition [ 54 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…These observations pointed to the fact that the addition of filler particles improved the wear-resistance property of the polymer matrix [ 54 ]. Furthermore, the particle uniformity and particle morphology of the added particles strongly affected the optimum concentration of the particles in the composite as high concentration (0.8 Wt%) of the commercial irregular and nonuniform particles (Fig.…”
The current study focuses on the fabrication of calcium hydroxyapatite (Ca10(PO4)6(OH)2) (HA) in a nanorange having whiskers- and cubic-shaped uniform particle morphology. The synthesized HA particles hold a promising feature as reinforcement fillers in dental acrylic resin composite. They increase the efficacy of reinforcement by length and aspect ratio, uniformity, and monodispersity. Therefore, the acrylic resin was reinforced with the as-synthesized monodispersed HA filler particles (0.2–1 Wt%). The presence of filler particles in the composite had a noticeable effect on the tribological and mechanical properties of the dental material. The morphological effect of HA particles on these properties was also investigated, revealing that cubic-shaped particles showed better results than whiskers. The as-fabricated composite (0.4 Wt%) of the cubic-shaped filler particles showed maximum hardness and improved antiwear/antifriction properties. Particle loading played its part in determining the optimum condition, whereas particle size also influenced the reinforcement efficiency. The current study revealed that particle morphology, particle size, uniformity, etc., of HA fillers, greatly influenced the tribological and mechanical properties of the acrylic resin-based nanocomposite. Improvement in the tribological properties of HA particle-reinforced acrylic resin composites (HA–acrylic resin) followed the trend as AR < CmC < WC < CC.
“…Besides, the wear debris of DLC coated UHMWPE is only carbon debris after depositing which may decrease the osteolysis [146]. Poly (methyl methacrylate)-hydroxyapatite hybrid coating on UHMWPE has stronger adhesive force with substrate, lower friction coefficient and wear rate than poly (methyl methacrylate) coating [147]. Both polymethylmethacrylate and hydroxyapatite have good biocompatibility and hydroxyapatite has better osteoinduction ability, therefore, this hybrid coating has potential to be employed in biomedicine.…”
Tribological phenomena abundantly exist in living beings, especially in human beings, such as teeth, eyes, bones, skins, heart valves and so on, and it is of meanings to reveal the mechanism of tribology in human body and fabricate artificial biomaterials to replace the damaged tissues to release the pain of patients. Alloys, ceramics and polymers are three uppermost materials used in engineering and some of them play a crucial role in biomedicine. In the paper, we provide an overview of the tribological behaviors of artificial biomaterials including alloys, ceramics and polymers. We aim to provide fundamental mechanistic and applications of tribological biomaterials, while emphasizing the advantages and disadvantages of various kinds of tribological biomaterials. Finally, some challenges and the potential promising breakthroughs are also succinctly highlighted in this field.
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