Tribological properties of ethylene–propylene–diene rubber + polypropylene + thermal‐shock‐resistant ceramic composites

Abstract

This work is part of a program on composites used in thermoelectric devices. Tribological properties of dynamic vulcanizate blends of polypropylene and ethylene-propylene-diene rubber filled with 5 wt% of microscale powder have been studied. The microscale thermal-shock-resistant ceramic filler contains α-Al 2 O 3 , mullite (3Al 2 O 3 · 2SiO 2 or 2Al 2 O 3 SiO 2 ), β-spodumene glass-ceramic and aluminium titanate. We found that our ceramic particles are abrasive; they cause strong abrasion of softer steel ball surfaces during dry sliding friction. To overcome the difficulty of particle dispersion and adhesion, the filler was modified through grafting using three types of organic molecules. Dry sliding friction was measured using four types of counter-surfaces: tungsten carbide, Si 3 N 2 , 302 steel and 440 steel. Thermoplastic vulcanizate filled with neat ceramic powder shows the lowest friction compared to composites containing the same but surface-treated powder. We introduce a 'bump' model to explain the tribological responses of our composites. 'Naked' or untreated ceramic particles protrude from the polymer surface and cause a decrease of the contact area compared to neat polymer. The ball partner surface has only a small contact area with the bumps. As contact surface area decreases, so does friction and the amount of heat generated during sliding friction testing. Chemical coupling of the ceramic to the matrix smoothens the bumps and increases the contact surface, giving a parallel increase in friction.

Improvement of Scratch and Wear Resistance of Polymers by Fillers Including Nanofillers

“…Microsize such particles were put into a thermoplastic vulcanizate (TPV), namely blends of polypropylene (PP) and ethylene-propylene-diene (EPDM) rubber at the concentration of 5 wt % [24]. The fillers included corundum (α-Al 2 O 3 ), mullite (3Al 2 O 3 .…”

Effects of polyimide/silica and polyimide/pores fillers on the morphology, thermal, mechanical, and tribological properties of polytetrafluoroethylene composites

“…First, the rolling effect of small amount of nanoparticles contributes to the decrease in the COF and wear rate of polymer composites . Second, fillers decrease the contact area between polymer composites and counterpart, which contributes to the decrease in the COF and wear rate of polymer composites . Third, SiO 2 nanoparticles improve the load capacity of PI/SiO 2 and thermal resistance of SiO 2 ‐PI fillers is higher than that of pure PI, which is helpful to reduce the deformation of SiO 2 ‐PI fillers under frictional load.…”

Structure and Properties of Burnished and Nitrided AISI D2 Tool Steel

“…Quite understandably, much research effort is expended in providing steels with a protection from corrosion [16]. The issue of wear concerns only applications when moving parts are involved [17].…”