Yellowing and Brittle Surface of Pads
Pads used in jacks and industrial lifting equipment, particularly those made of polyurethane or rubber, may develop yellowing and surface brittleness over time. This condition can compromise performance, safety, and longevity.
1. Causes of Yellowing and Brittleness
UV Exposure: Prolonged exposure to sunlight or ultraviolet radiation accelerates polymer degradation, leading to discoloration and brittleness.
Oxidation: Reaction with oxygen in the air causes chemical breakdown of polymer chains, especially in polyurethane, resulting in hardening and yellowing.
Thermal Aging: High-temperature environments accelerate chemical degradation, reducing elasticity and making the surface fragile.
Chemical Exposure: Contact with oils, solvents, or cleaning agents can chemically attack the pad material, causing discoloration and surface cracking.
Poor Material Quality: Substandard formulations or inadequate curing can make pads more susceptible to environmental aging.
2. Effects of Surface Yellowing and Brittleness
Loss of Elasticity: Brittle surfaces reduce the pad’s ability to absorb shocks and distribute loads.
Increased Risk of Cracking: Yellowed, brittle pads are prone to micro-cracks, which can propagate under load.
Reduced Safety: Compromised surface integrity increases the risk of slipping, uneven lifting, or pad failure.
Accelerated Wear: Fragile surfaces wear more quickly, potentially damaging both the pad and the equipment it supports.
3. Preventive Measures
Material Selection: Use UV-resistant and high-quality polyurethane or rubber with proper stabilizers.
Environmental Control: Minimize exposure to sunlight, heat, and harmful chemicals during storage and use.
Regular Inspection: Periodically check for color changes, hardening, or surface cracks; replace degraded pads promptly.
Proper Storage: Store pads in cool, dry, shaded locations away from chemical contaminants.
4. Conclusion
Yellowing and brittleness of pad surfaces result from UV exposure, oxidation, thermal aging, chemical attack, and material quality issues. Preventive measures, proper storage, and regular inspection are essential to maintain pad performance and ensure safe lifting operations.
References
Gent, A. N. Engineering with Rubber: How to Design Rubber Components. Hanser Publishers, 2012.
Lake, G. J. “Fatigue and Fracture of Elastomers.” Rubber Chemistry and Technology, 2000.
ASTM D412 – Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers—Tension.
ISO 7619-1 – Rubber, Vulcanized or Thermoplastic — Determination of Indentation Hardness.
ASTM D2240 – Standard Test Method for Rubber Property—Durometer Hardness.
