Influence of Water Absorption on Static Friction of Pure and Friction-Modified PA6 Polymers

Abstract:

In the present study, static coefficients of friction of pure and friction modified (FM) polyamide 6 (PA6) polymers against primer-coated steel surfaces were investigated under a series of nominal contact pressures and by considering the influences of water absorption by the polymer, temperature, counter-body surface roughness and lubrication conditions. Under the majority of the test conditions investigated, FM PA6 exhibited lower static friction than pure PA6. Under unlubricated conditions, this was due to the low adhesion of the FM PA6 provided by its friction modifying inclusions; while under lubricated conditions, a combination of softening due to water absorption and decreased adhesion provided by its friction modifiers enabled lower static friction, especially at medium and high contact pressures.

• Periodical: Key Engineering Materials (Volume 799)
• Pages: 59-64
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.799.59
• Online since: April 2019
• Authors: Igor Velkavrh, Stefan Klien, Joel Voyer, Florian Ausserer, Alexander Diem
• Keywords: Adhesion, Deformation, Polymer Tribology, Sliding Contacts, Water Absorption

References

[1] J. K. Lancaster, A review of the influence of environmental humidity and water on friction, lubrication and wear, Tribol. Int. 23 (1990) 371–389.

DOI: 10.1016/0301-679x(90)90053-r

[2] S. C. Cohen, D. Tabor, The Friction and Lubrication of Polymers, Proc. R. Soc. Math. Phys. Eng. Sci. 291 (1966) 186–207.

[3] G. Erhard, Friction and wear behaviour of polymer materials (in German: Zum Reibungs- und Verschleißverhalten von Polymerwerkstoffen), University Karlsruhe, Karlsruhe, Germany, (1980).

[4] N. K. Myshkin, M. I. Petrokovets, A. V. Kovalev, Tribology of polymers: Adhesion, friction, wear, and mass-transfer, Tribol. Int. 38 (2005) 910–921.

DOI: 10.1016/j.triboint.2005.07.016

[5] N. Myshkin, A. Kovalev, Adhesion and surface forces in polymer tribology – A review, Friction 6 (2018) 143–155.

DOI: 10.1007/s40544-018-0203-0

[6] ISO 6743-9:2003, Lubricants, industrial oils and related products (class L) — Classification — Part 9: Family X (Greases), https://www.iso.org/obp/ui/fr/#iso:std:iso:6743:-9:ed-2:v1:en.

DOI: 10.3403/30050551

[7] J. Voyer, S. Klien, I. Velkavrh, F. Ausserer, A. Diem, Static and dynamic friction of pure and friction-modified PA6 polymers in contact with steel surfaces – influence of surface roughness and environmental conditions, submitted to Lubricants (2018).

DOI: 10.3390/lubricants7020017

[8] S. K. Sinha, B. J. Briscoe (Eds.), Polymer tribology, Imperial College Press, London, (2009).