Nanoindentation of high performance semicrystalline polymers: A case study on PEEK

Voyiadjis, George Z.; Samadi-Dooki, Aref; Malekmotiei, Leila

doi:10.1016/j.polymertesting.2017.05.005

Cited by 50 publications

(24 citation statements)

References 32 publications

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“…The experimental results, including the indentation hardness, indentation modulus, and plane strain modulus, are listed in Table 3. A smaller indentation depth of composite materials in nanoindentation tests generally indicates better nanomechanical properties under the same load conditions [48]. As illustrated in Fig.…”

Section: Nanomechanical Properties Of Na-mmt/pes/ Ptfe Ternary Composmentioning

confidence: 83%

RETRACTED ARTICLE: Thermal, mechanical, and tribological properties of sodium-montmorillonite-nanoparticle-reinforced polyethersulfone and polytetrafluoroethylene ternary composites

Yan

Xue

et al. 2020

Friction

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Polyethersulfone (PES) and polytetrafluoroethylene (PTFE) blend composites reinforced with sodiummontmorillonite (Na-MMT) nanoparticles were prepared by cold molding and vacuum sintering. The effects of the Na-MMT content on the thermal, nanomechanical, and tribological properties of the Na-MMT/PES/PTFE ternary composites were investigated in detail. The results indicate that at the optimal content, Na-MMT nanoparticles can be uniformly dispersed in the PES/PTFE binary blend composites and generate strong interfacial bonding with the polymeric matrix. Both the thermal stability and the nanomechanical properties of the PES/PTFE binary blend composites are clearly improved by the incorporation of Na-MMT nanoparticles. Among these PTFE-based composites, the Na-MMT/PES/PTFE ternary composite containing 10.0 wt% of Na-MMT nanoparticles exhibits the optimal friction and wear performance. Compared with those of the PES/PTFE blend composite, the friction coefficient (μ = 0.16) and wear rate (k = 2.63 × 10 −14 m 3 /(N•m)) of the 10.0 wt% Na-MMT/PES/PTFE ternary composite are 19.1% and 97.2% lower, respectively. The significant enhancement of the wear resistance of the Na-MMT/PES/PTFE ternary composite is attributable to the formation of PTFE self-lubricating transfer films. The transfer films generated on the worn surfaces of GCr15 steel balls can prevent direct contact between the PTFE composites and their metal counterparts, thereby protecting the polymer composites from damage.

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Section: Nanomechanical Properties Of Na-mmt/pes/ Ptfe Ternary Composmentioning

confidence: 83%

RETRACTED ARTICLE: Thermal, mechanical, and tribological properties of sodium-montmorillonite-nanoparticle-reinforced polyethersulfone and polytetrafluoroethylene ternary composites

Yan

Xue

et al. 2020

Friction

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“…In this study, since the volume percentage of CNF is very small, the effect of thermal coefficient mismatch between LDPE and CNF is negligible. Moreover, it was previously found that mechanical polishing has no effect on the measured NI values for polymer composites [36,37]. Therefore, having the knowledge that all the CNF/LDPE samples in this study underwent the same thermal processing conditions and have no plastic deformation, and more importantly, all the indentations were performed on a plane surface parallel to the longitudinal central plane of the dog bone samples (i.e., a plane on which thermal history is virtually identical).…”

Section: Methodsmentioning

confidence: 99%

Surface Mechanical Characterization of Carbon Nanofiber Reinforced Low-Density Polyethylene by Nanoindentation and Comparison with Bulk Properties

2019

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Surface mechanical properties of low-density polyethylene (LDPE) reinforced by carbon nanofibers (CNFs) up to 3% weight load were investigated using nanoindentation (NI). Surface preparation of the nanocomposite was thoroughly investigated and atomic force microscopy (AFM) was used to analyze the surface roughness of the polished surfaces. The dispersion of nanofillers in the LDPE matrix was examined using scanning electron microscopy (SEM). The effect of various penetration loads on the results and scattering of the data points was discussed. It was found by NI results that the addition of 3% weight CNF increased the elastic modulus of LDPE by 59% and its hardness up to 12%. The nano/micro-scale results were compared with macro-scale results obtained by the conventional tensile test as well as the theoretical results calculated by the Halpin-Tsai (HT) model. It was found that the modulus calculated by nanoindentation was twice that obtained by the conventional tensile test which was shown to be in excellent agreement with the HT model. Experimental results indicated that the addition of CNF to LDPE reduced its wear resistance property by reducing the hardness to modulus ratio. SEM micrographs of the semicrystalline microstructure of the CNF/LDPE nanocomposite along with the calculated NI imprints volume were examined to elaborate on how increasing the penetration depth resulted in a reduction of the coefficient of variation of the NI data/more statistically reliable data.

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“…Nanoindentation measurements were performed on an iMicro nanoindenter (NANOMECHANICS, Inc.) equipped with a Berkovich tip. To evaluate the hardness of PEEK as a function of indentation depth, the continuous stiffness measurement (CSM) technique [39][40][41] was employed by applying a small, sinusoidally varying signal on top of a DC signal driving the indenter. The hardness at each indentation depth is determined by analyzing the response of amplitude and phase.…”

Section: Nanoindentation Measurementsmentioning

confidence: 99%

“…In all tests, hardness showed high values at indentation depth values <0.5 µm. These values are thought to be attributed to a phenomenon known as indentation size effect (ISE), and not regarded as physically significant because they are distorted by the inadequacies in the procedures applied to provide corrections for the imperfections in the tip geometry [41,47,48].…”

Section: Nanoindentation Investigations Of Peek Hardnessmentioning

confidence: 99%

Effect of Lubrication on Friction and Wear Properties of PEEK with Steel Counterparts

et al. 2019

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Poly-Ether-Ether-Ketone (PEEK) has been widely used for tribological applications with steel counterparts because of its superior mechanical and self-lubricating properties. Fluid lubrication has the potential to further improve the performance of PEEK/steel contacts but its effect has been shown to depend on the operating conditions. To elucidate these aspects and establish the mechanism of fluid lubrication, the friction and wear properties of the PEEK/steel contacts in both dry and poly-α-olefin (PAO) lubricated conditions were investigated by tribological tests and surface analytical techniques. The nanoindentation measurements showed that lubrication with PAO had a softening effect on the wear track of PEEK, but no correlation was established with the wear of PEEK. The tribological behavior, for both dry and lubricated contacts, was correlated with the thickness of PEEK transfer films on the steel counterparts. The thickness of these films, as determined by Electron Probe Micro Analysis (EPMA) and X-ray Photoelectron Spectroscopy (XPS), was controlled by the rates of their formation and removal and depended on the operating conditions. Moreover, lubrication with PAO inhibited not only the formation but also the removal of PEEK transfer films. This study thus sheds light on the mechanism of fluid lubrication of the PEEK/steel contacts.

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Nanoindentation of high performance semicrystalline polymers: A case study on PEEK

Cited by 50 publications

References 32 publications

RETRACTED ARTICLE: Thermal, mechanical, and tribological properties of sodium-montmorillonite-nanoparticle-reinforced polyethersulfone and polytetrafluoroethylene ternary composites

RETRACTED ARTICLE: Thermal, mechanical, and tribological properties of sodium-montmorillonite-nanoparticle-reinforced polyethersulfone and polytetrafluoroethylene ternary composites

Surface Mechanical Characterization of Carbon Nanofiber Reinforced Low-Density Polyethylene by Nanoindentation and Comparison with Bulk Properties

Effect of Lubrication on Friction and Wear Properties of PEEK with Steel Counterparts

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