Connection of surface tension with multiple tribological properties in epoxy + fluoropolymer systems

Abstract

Contact angles of free liquids on solid samples were measured and the van Oss-Good method was applied for evaluating surface tensions of the solids. A parachor method was used for comparison: in this case the respective values were calculated for the polymer solids from molecular and group contributions. Surface tensions were computed from the parachors and the two methods compared. Effects of varying the fluoropolymer added to the epoxy before curing are discussed. For a given fluoropolymer, effects of changing its concentration on surface tension have also been evaluated and compared to the changes in scratch resistance (scratch penetration depth, recovery depth) and in static and dynamic friction. Morphological and phase structure changes are reflected in all these properties, showing a strong connection between the surface tension and tribological properties.

Ripple polystyrene nano-pattern induced by KrF laser

“…plasma treatment or exposure by UV-lamp, so that the surface layer could be altered [15]. Increase of surface energy induced by these methods influences not only the adhesion, but also its tribological properties [16]. Laser beam allows performing precise changes of only small fragments or thickness of surface layer [17].…”

Pressure–volume–temperature properties of an epoxy+fluorinated poly(aryl ether ketone) system

“…[5], the presence of a low concentration of the fluoropolymer disturbs the epoxy structure. We recall here the work by Arrighi and her colleagues [17] using neutron diffractometry to evaluate alterations in a polymer structure by addition of a second component.…”

“…When increasing the concentration of 12F-PEK up to 5%, both curves (at 24 C or 70 C) pass first through a minimum, then through a maximum around 10% and finally decrease again. The complex shape of the curve can be explained taking into account in particular the dependence of the solid polymer surface tension g on the FP concentration [5].…”

“…At the surface we have found that the extrema in static friction, dynamic friction, penetration depth and residual depth in scratching all corresponds to extrema in surface tension [5]. In the present paper we report results of determination of equation of state (EOS) for the same system.…”

Poly(methyl acrylate) plus Mesoporous Silica Nanohybrids: Mechanical and Thermophysical Properties

“…The present approach has been applied to PMA; applying it to thermosets might be worthwhile -also given the large and still increasing range of application of epoxies [35 -37]. We recall that introduction of a fluoropolymer by blending before curing is a worthwhile option in improving tribological properties of a commercial epoxy [38]. Polymer irradiation is another such option [39 -42].…”