Wear resistance refers to the ability of vulcanized rubber to resist material loss caused by surface abrasion under frictional force.
1. Abrasive wear
Wear caused by rough surfaces with diamond-shaped protrusions.
Rate: 10³–10⁵ μm/h.
2. Rolling (curl) wear
Wear on relatively smooth surfaces.
Rate: 10²–10⁴ μm/h.
3. Fatigue wear
Wear occurring under constant friction force on rough surfaces.
Rate: 10⁰–10² μm/h.
4. Impact wear (abrasion by irregular abrasives)
Wear under impact of hard abrasive particles (some with sharp edges), such as sand mill liners and rubber rolls for rice hulling.
Rate: 10³–10⁶ μm/h.
1. In common diene rubbers, the wear resistance ranking is:
BR > SSBR > ESBR > NR > IR
2. Rubbers with low glass transition temperature and good molecular chain flexibility show higher wear resistance.
3. Wear resistance of SBR improves with increasing molecular weight.
4. Wear resistance of NBR improves with increasing acrylonitrile content.
5. Wear resistance of EPDM is similar to that of SBR.
6. Polyurethane (PU) has the best wear resistance among rubbers.
7. Higher rigidity intensifies fatigue wear and impact wear, but relieves abrasive wear and rolling wear.
Fatigue applications: 35–55 Shore hardness
Impact applications: 50–70 Shore hardness
8. Wear resistance of rubber blends does not follow the additivity rule. Closer polarity between components leads to better wear resistance than the additive value.
9. Wear resistance reaches an optimal value with increasing crosslink density (usually longer than T90). The combination of sulfur and accelerator CZ provides good wear resistance.
10. Wear resistance improves with smaller filler particle size, higher surface activity, better dispersion, and higher structure. There is an optimal filler loading:
NR: 45–50 phr
IR & SBR: 50–55 phr
Oil-extended SBR: 60–70 phr
BR: 90–100 phr
11. Anti-fatigue and anti-aging agents help improve wear resistance.
12. Adding softeners generally reduces wear resistance.
13. Adding high styrene, PE, PP, PVC, nylon, polyoxymethylene, etc., smoothes the rubber surface and enhances wear resistance.
Adding short fibers to rubber improves wear resistance.
