Assessing quantitative metrics of transfer film quality as indicators of polymer wear performance

Polyoxymethylene (POM)-based composites with polytetrafluoroethylene (PTFE) filler and silicone gum have been prepared by melt extrusion to enhance the wear resistance and friction lubrication of POM without compromising the other desired properties such as modulus, toughness/impact strength, notch insensitivity, and thermal stability. The compounded material was injection molded to prepare test specimens, and their physico-mechanical properties were evaluated. In addition, thermal and tribological characteristics of the composites were also studied. The addition of silicone into POM/PTFE composites could enhance the formation of stable transfer film on the mating surface during sliding contact, thus improving the friction and wear performance, as silicone forms synergistic mixture with PTFE. It was found that the tensile, flexural, and notched impact strength remained almost constant for all the formulations. The use of PTFE improved the unnotched impact strength (from 35.5 to 42.9 kJ m−2). The toughening effect can be attributed to the dissipation of impact energy through soft PTFE and ductile silicone phase. Differential scanning calorimeter results revealed that there are no negative effects on POM crystallinity due to the presence of PTFE and silicone. The wear behavior of composites has been investigated under dry sliding conditions at different normal loads and sliding velocities at room temperature. The POM/PTFE/silicone (90/8/2 wt/wt%) formulation exhibits better wear-resistant behavior in the present study.

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Wear of polymers

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1243/135065002762355325 ◽

2002 ◽

Vol 216 (6) ◽

pp. 401-413 ◽

Cited By ~ 101

Author(s):

B. J. Briscoe ◽

S. K. Sinha

Keyword(s):

Wear Mechanisms ◽

Sliding Wear ◽

Transfer Film ◽

Third Body ◽

Contact Conditions ◽

Material Parameters ◽

Sliding Surfaces ◽

The Third ◽

Polymer Wear ◽

Made In

This paper reviews some of the recent progress which has been made in the area of the sliding wear of polymers. Wear mechanisms are classified under three broad approaches which reflect primarily the way this subject has been historically studied. It is demonstrated here that the wear of polymers is influenced by the contact conditions, the bulk mechanical properties of the polymer and the properties of the ‘third body’, which generally appears in the form of transfer film or degraded polymer particles between two sliding surfaces. Further, this paper establishes a link between the different contact and material parameters and shows how they are important in elucidating the generic wear mechanisms for polymers. The effects of environment and lubrication upon polymer wear are briefly explained in terms of the chemical interactions between the liquid phase and the polymer. The capabilities and limitations of current predictive wear models for polymeric contacts are also highlighted.

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Average Worn Profile of Tires in Europe

Tire Science and Technology ◽

10.2346/tire.14.420303 ◽

2014 ◽

Vol 42 (3) ◽

pp. 166-184 ◽

Cited By ~ 1

Author(s):

Frédéric Biesse ◽

Jérôme Mahé ◽

Nicolas Lévy

Keyword(s):

End Of Life ◽

Development Process ◽

Measurement Process ◽

European Countries ◽

Analysis Method ◽

Wear Performance ◽

Usual Behavior ◽

Wear Tests ◽

Pattern Width

ABSTRACT Tire tread wear is a key issue in the tire development process and for tire customers. In order to measure the wear performance, tire manufacturers usually proceed to wear tests and calculate the tire life from those tests. An important point in this tire life computation is the criteria chosen for defining the tire's end of life. In Europe, there is a legal minimum tread depth set to 1.6 mm applicable to 75% of the tread pattern width. However, outside those 75% (i.e., on the shoulder part), no clear and shared limit is defined. Also, the usual behavior of customers to decide when their tires should be changed is not well known. The goal of this 2012 study was to identify an average worn profile of tires in Europe and the behavior of customers for replacing their tires. For that, 3000 tires worn out by customers have been collected in scrapyards and measured in five European countries. In this article, we will present the tire collecting method, the measurement process, the analysis method, and some general results and statistics on this 3000 tire database. Finally, the method to compute the average end of life profile and the resulting profile is given.

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