Showing papers on "Friction modifier published in 1974"

The Nature of Polymer Friction

Abstract: The sliding friction between a solid polymer and another solid (polymer, metal, glass) usually is determined by the work of deformation of the polymer(s). The ratio F/N of frictional force to normal load commonly decreases for polymers when N increases because F is proportional to Nm+n and m+n < 1; m and nm are defined by the expressions w = k1Nm and d = k2Nn; w and d are the width and the depth of the disturbed material; k1 and k2 are proportionality constants. Friction in reproducible sliding is never caused by adhesion. The absence of adhesion is proved by the ease of normal separation of slider and support; and the cause of this absence is the presence of weak boundary layers (air, moisture, etc.) between the two. When these layers are eliminated, adherence of slider to support occurs and no usual sliding is possible. Attempts to correlate F with the true area S of contact are misleading because work must be performed to achieve this S. The common determinations of S are unsatisfactory. Theoretical and experimental determinations of the work done during frictional deformation of viscoelastic polymers is needed to account for the observed friction.

Effect of strain hardening on friction behavior of iron lubricated with benzyl structures

Abstract: Sliding friction experiments were conducted with iron, copper, and aluminum in contact with iron in various states of strain. The surfaces were examined in dry sliding and with various benzyl compounds applied as lubricants. Friction experiments were conducted with a hemispherical rider contacting a flat disk at loads of from 50 to 600 grams with a sliding speed of 0.15 cm/min. Results indicate that straining increases friction for dry sliding and for surfaces lubricated with certain benzyl structures such as dibenzyl disulfide. With other benzyl compounds (e.g., benzyl formate), friction coefficients are lower for strained than for annealed iron.