Polymeric compositions and products of low wear and of low friction

A polymer composition comprising:

• a siloxane polymer with repeat units of the following general Formula 3:
• wherein n is any integer from 40 to 50,000,
• wherein the siloxane polymer provides a constant average coefficient of friction over a time period of sixty minutes of wear testing;
• and
• wherein the coefficient of friction is measured using a pin-on-disk test against Si3N4 at room temperature for a period of 1 hour at a sliding speed of 1 mm/s, a sliding distance of 14 mm, a rotation of 1 rpm and a static pressure of 15 N using a tribometer.

A polymer composition comprising:

• a poly(tetramethyl-p-silphenylenesiloxane) (PTMPS) polymer having a weight average molecular weight of from 10,000 Da to 3,000,000 Da;
• wherein the PTMPS polymer provides a coefficient of friction stable over a time period of sixty hours of wear testing;
• and
• wherein the coefficient of friction is measured using a pin-on-disk test at a temperature of from 20° C. to 22° C. for a period of about 60 hours at a sliding speed of from 0.4 to 0.5 ft/min, a rotation of about 2 rpm and a pressure of about 25000 Psi under a normal load of about 10 N using a tribometer.

A wear engagement system comprising:

• a polymeric surface comprising a poly(tetramethyl-p-silphenylenesiloxane) (PTMPS) polymer;
• and
• a modified countersurface engaging the polymeric surface at a pressure of from 1 MPa to 10 MPa, a velocity of 200 mm/s to 2000 mm/s, and a contact radius of about 80 mm for a sliding distance of about 0.5 m/rev,
• wherein the modified countersurface comprises an original countersurface of a disk and a transfer layer formed of particles shed from the polymeric surface comprising particles of the PTMPS polymer during an initial wear period of the wear engagement system.

An article comprising:

• a polymer block comprising a poly(tetramethyl-p-silphenylenesiloxane) (PTMPS) polymer with repeat units of the following general Formula 3:
• a wear track along a direction of wear track on a surface of the polymer block after the article is subject to a block-on-disk test against a countersurface of a disk at a pressure of from 1 MPa to 10 MPa, a velocity of 200 mm/s to 2000 mm/s, and a contact radius of about 80 mm for a sliding distance of about 0.5 m/rev;
• and
• worn PTMPS polymer particles substantially along the sides of the wear track in a direction perpendicular to the direction of wear track;
• wherein n is any integer from 5 to 50,000;
• wherein the wear track is formed by the countersurface of the disk engaging the surface of the polymer block along the direction of wear track.

A method of modifying a countersurface, the method comprising:

• disposing an unmodified countersurface to frictionally engage a surface of a polymer block comprising a poly(tetramethyl-p-silphenylenesiloxane) (PTMPS) polymer;
• transferring a plurality of PTMPS polymer particles from the surface of the polymer block to the countersurface during a frictional engagement;
• and
• modifying the countersurface to include an engaged transfer layer of the transferred PTMPS polymer particles fixedly deposited on the unmodified countersurface.