A route to wear resistant PTFE via trace loadings of functionalized nanofillers

Burris, David L.; Zhao, Su; Duncan, Renée K.; Lowitz, J.; Perry, Scott S.; Schadler, Linda S.; Sawyer, W. Gregory

doi:10.1016/j.wear.2008.12.116

Cited by 99 publications

(48 citation statements)

References 33 publications

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“…Obviously such additives should be selected which bear the same functional groups evolved according to above schemes, which may enter in reaction with them, or which have possible ligands for the supposed complex formation. The latter aspect seems to be confirmed by the ultralow wear results measured for PTFE with alumina and silicate type nanofillers [6][7][12][13][14][15]. Suitable functional groups for complexing can be produced, however, also on carbonaceous nanofillers, such as CNT and graphene derivatives.…”

Section: Introductionmentioning

confidence: 71%

“Ultralow” sliding wear polytetrafluoro ethylene nanocomposites with functionalized graphene

Padenko

Rooyen

Wetzel

et al. 2016

Journal of Reinforced Plastics and Composites

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Abstract:The dry friction and sliding wear behavior of sintered PTFE containing various amounts of functionalized graphene (GR) were studied in this work. GR was incorporated in 0, 0.25, 0.75, 1, 2 and 4 vol%, respectively. Sliding wear tests were performed in ring(metal)-on-plate(PTFE) (ROP) test rig under ambient temperature setting 1 m/s sliding speed and 1 MPa contact pressure. The dynamic coefficient of friction (COF) and specific wear rate (ws) data were determined. Very low COFs (0.12-0.14) were measured for PTFE containing 2 or 4 vol% GR which was attributed to the formation of a tribofilm on the countersurface. ws went through a maximum (peaked at doubling that of the unmodified PTFE at about 0.75 vol% GR) as a function of GR content. Ultralow ws data in the range of 10 -6 mm 3 /(N.m) were measured for the PTFE nanocomposites with 2 and 4 vol% GR. This was reasoned by the formation of a robust tribofilm, the development of which was followed by scanning electron microscopy (SEM) by inspecting the worn surface of PTFE nanocomposites and that of the steel ring of the ROP test rig. Fourier transform infrared spectroscopic results confirmed the formation of carboxyl groups in the tribofilm. They were 2 supposed to react with the functional groups of GR and to create complexes with the metal countersurface ensuring the tribofilm with high adhesion and cohesion strengths.

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Section: Introductionmentioning

confidence: 71%

“Ultralow” sliding wear polytetrafluoro ethylene nanocomposites with functionalized graphene

Padenko

Rooyen

Wetzel

et al. 2016

Journal of Reinforced Plastics and Composites

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“…With 40 nm alpha-phase alumina nanoparticles treated in an effort to improve dispersion, Burris et al [16] recently achieved wear rates that were reduced more nearly to 1 9 10 -7 mm 3 /Nm and similarly constant despite reductions in filler content to as low as 0.13%, before rapidly increasing towards the *10 -3 mm 3 /Nm wear rate of unfilled PTFE upon further filler content reduction. If considered to be a mixture of its constituents, invariance of a composite characteristic such as this wear rate over a range of filler content can exist if the wear characteristic contributed by the matrix is not independent but is instead modified by the presence of the filler, particularly in the region near the filler.…”

Section: Effect Of Filler Contentmentioning

confidence: 99%

“…If considered to be a mixture of its constituents, invariance of a composite characteristic such as this wear rate over a range of filler content can exist if the wear characteristic contributed by the matrix is not independent but is instead modified by the presence of the filler, particularly in the region near the filler. Burris et al [16] have shown by atomic force microscopy of microtomed sections that alpha-phase alumina nanoparticles cause a substantial modification in morphology, from heterogeneous bands of lamellar crystals for unfilled PTFE to a homogeneous crystalline morphology that was coarsened and equiaxed in the nanocomposite. As such PTFE morphology modification is believed to be induced by the alpha-phase alumina surface, it can be hypothesized that microparticles may cause only negligible effects on the PTFE, while nanoparticles with such high surface-to-volume ratio instead provide an effect on a PTFE matrix that remains nearly complete even to an extremely low filler content.…”

Section: Effect Of Filler Contentmentioning

confidence: 99%

Coupled Effect of Filler Content and Countersurface Roughness on PTFE Nanocomposite Wear Resistance

2009

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In tests of PTFE with 2.9% volume content alpha-phase alumina nanoparticles (40 or 80 nm) in sliding reciprocation against polished steel, wear rates of *10 -7 mm 3 /Nm were measured which is four orders-ofmagnitude lower than unfilled PTFE and two orders-ofmagnitude lower than with microparticles (0.5 or 20 lm) of more conventional filler size. This was similar to that previously reported in unidirectional sliding, and did not vary greatly with stroke of reciprocation. For a microfilled PTFE, the wear rate gradually increased towards that of unfilled PTFE as filler content was reduced, whereas nanofilled PTFE maintained relatively constant *10 -7 mm 3 /Nm to filler contents as low as 0.18% before reverting towards the rapid wear rate of unfilled PTFE. Lightly filled nanocomposites depend upon low countersurface roughness to maintain such low wear rate, and with increasing roughness the wear rate was found to transition at a critical value to a wear rate of *10 -5 mm 3 /Nm. Nanocomposites with higher filler contents were able to retain the low wear rates against rougher countersurfaces, as the critical roughness at which this wear resistance was lost tended to increase with the square of the filler content. Upon encountering extremely high countersurface roughness in the range R a = 6-8 lm, nanocomposites at each filler content eventually increased in wear rate to *10 -4 mm 3 /Nm. The steel countersurface did not appear to play an important role in the extreme wear resistance of these alumina nanofilled PTFE composites, as comparable performance was also displayed against alumina countersurfaces.

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“…TEM analysis shows that that the treated nanoparticles were dispersed throughout the PTFE matrix whereas the untreated nanoparticles were forming clusters. The improvement of wear resistance was seen by loading treated nanoparticles and by adding untreated nanoparticles the wear reduction is significant [120].…”

Section: Nano-composites Of Ptfementioning

confidence: 99%

Performance properties and applications of polytetrafluoroethylene (PTFE)—a review

Dhanumalayan

Joshi

2018

Adv Compos Hybrid Mater

338

143

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High-performance commodity polymers are in demand due to low cost, durability, easy productivity, and recycling ability. This article comprises a survey on the performance properties of polytetrafluoroethylene (PTFE) fluoropolymer. It is a well-known choice for coatings, insulation, thermal sealing, lubrication, bearings, and clinical applications. PTFE was engineered in many forms as a function of loading nano and micro fillers for different purposes and the improved properties and performance were addressed by the researchers. Hence, we disclosed the various casting routes of PTFE which is feasible for reliable processing to serve in domestic and industrial applications.

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A route to wear resistant PTFE via trace loadings of functionalized nanofillers

Cited by 99 publications

References 33 publications

“Ultralow” sliding wear polytetrafluoro ethylene nanocomposites with functionalized graphene

“Ultralow” sliding wear polytetrafluoro ethylene nanocomposites with functionalized graphene

Coupled Effect of Filler Content and Countersurface Roughness on PTFE Nanocomposite Wear Resistance

Performance properties and applications of polytetrafluoroethylene (PTFE)—a review

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