Abrasion Resistance Testing of Rubber After Aging: Standards, Methods, and Evaluation

Aging fundamentally alters the surface chemistry, hardness, and mechanical integrity of rubber materials, which directly affects their wear performance in service. Abrasion resistance testing of rubber after aging combines accelerated aging protocols with standardized wear measurement to predict the long-term durability of products such as tires, seals, conveyor belts, and footwear. This article explains the testing standards, sample requirements, methodologies, and evaluation criteria used by accredited third-party laboratories and manufacturers worldwide.

Technical Overview

Rubber materials inevitably degrade during storage and service due to heat, oxygen, ozone, ultraviolet radiation, humidity, and contact with fluids. These aging factors trigger oxidation, chain scission, additional crosslinking, and surface cracking, which alter hardness, modulus, tensile strength, and—critically—abrasion resistance. Because laboratory wear data obtained on fresh, unaged compounds often overstate real-world durability, engineers increasingly require abrasion measurements to be performed on artificially aged specimens.

Abrasion resistance testing of rubber after aging is a two-stage evaluation. In the first stage, specimens are subjected to controlled accelerated aging in accordance with standards such as ISO 188, ASTM D573, ASTM D1149, and ISO 4892. In the second stage, the aged specimens are tested on standardized abrasion apparatus, most commonly the rotating cylindrical drum device specified in ISO 4649, ASTM D5963, and GB/T 9867. The combined result quantifies how much wear resistance is lost after a defined aging exposure, enabling service-life prediction, formulation comparison, and compliance verification.

Testing Samples

Tires and Tire Components

Tread compounds, sidewall rubber, and retread materials are core sample types. Heat-aged tread specimens are evaluated to simulate years of rolling contact, ozone exposure, and road-surface wear under high-temperature operating conditions.

Seals, Gaskets, and O-Rings

Static and dynamic sealing elements made of NBR, EPDM, FKM, or silicone rubber are aged in air, ozone, or service fluids, then assessed for surface wear that could compromise sealing performance in hydraulic and pneumatic systems.

Conveyor Belts, Hoses, and Rubber Rollers

Cover compounds from conveyor belts and protective layers of industrial hoses undergo thermal and ozone aging followed by drum abrasion testing, since cover wear life is a primary maintenance cost driver in mining and material handling.

Footwear Soles, Mats, and Rubber Sheets

Outsole compounds, anti-slip mats, and molded sheet goods are aged under UV and heat to reflect warehouse storage and retail display conditions, then tested to confirm wear performance after degradation has begun.

Standard Laboratory Coupons

For drum abrasion testing, cylindrical or disc specimens with a diameter of approximately 16 mm and a minimum thickness of 6 mm are die-cut from cured sheets. Specimens must be flat, free of porosity, and trimmed of mold flash, since surface defects strongly influence measured volume loss.

Testing Items

The combined aging-plus-abrasion evaluation typically reports the following parameters:

• Relative volume loss after abrasion, expressed in mm³, corrected for the abrasiveness of the test run against a calibrated standard rubber.
• Abrasion resistance index (ARI), the percentage ratio of the volume loss of a standard reference compound to that of the tested compound.
• Mass loss and volume loss of the specimen over a fixed abrasion path length.
• Hardness before and after aging, measured with a Shore durometer to ISO 48-4 or ASTM D2240.
• Tensile strength, elongation at break, and 100% and 300% modulus before and after aging, per ISO 37 or ASTM D412.
• Density of the compound, determined per ISO 2781 or ASTM D297, required for converting mass loss to volume loss.
• Surface condition assessment, including the degree of cracking, chalking, or glazing observed after aging exposure.

Testing Methods

Stage One: Accelerated Aging

Prior to abrasion measurement, specimens are aged using one or more of the following protocols, selected to match the dominant degradation mechanism in the intended application:

• Air oven thermal aging at elevated temperature, typically 70 °C to 100 °C for 24 to 168 hours, per ISO 188 or ASTM D573.
• Ozone aging at 50 pphm ozone concentration under static or dynamic strain, per ISO 1431-1 or ASTM D1149.
• Artificial weathering using xenon-arc lamps or fluorescent UV lamps with condensation cycles, per ISO 4892-2, ISO 4892-3, ASTM G155, or ASTM G154.
• Fluid immersion aging in oils, fuels, or service liquids, per ISO 1817 or ASTM D471.
• Humidity and thermal cycling, where condensation and temperature swings drive hydrolytic and mechanical degradation.

After aging, all specimens are reconditioned for at least 16 hours at 23 °C ± 2 °C and 50% ± 5% relative humidity before wear testing begins, ensuring dimensional and moisture equilibrium.

Stage Two: Rotating Cylindrical Drum Abrasion (DIN Method)

The reference method is ISO 4649, equivalent to ASTM D5963 and GB/T 9867. A specimen is pressed against the surface of a rotating drum covered with a bonded abrasive cloth of specified grit, under a vertical force of 10 N, over an abrasion path of approximately 40 m. The specimen may be held stationary or rotated during traversal depending on the chosen procedure. Mass loss is measured and converted to volume loss using the compound density, then normalized against a calibrated standard rubber to yield relative volume loss and the abrasion resistance index.

Pico Abrader Method

For tread-grade compounds, ASTM D2228 uses a Pico abrader in which three tungsten carbide knives rub against the specimen under controlled load and rotation. The method correlates well with tire tread wear and is particularly useful for comparing aged versus unaged tread formulations.

Taber Abraser Method

ASTM D3389 employs a rotating platform abraser with abrasive wheels such as the H-18 grade. It is suited to flat sheet products, coated fabrics, and rubber mats, and is frequently combined with UV aging for flooring and footwear evaluations.

NBS and Other Abrader Types

ASTM D1630 (NBS abrader) is used mainly for sole and heel materials, expressing results as the number of revolutions required to wear through a standard thickness. Selection among abrader types should reflect the wear mode—abrasive, fatigue, or adhesive—dominant in actual service.

Data Reduction and Reporting

The reported relative volume loss is calculated from specimen volume loss, the measured volume loss of a standard rubber tested in the same session, and the certified abrasiveness of the reference material. Results for aged specimens are then compared with unaged controls, and the retention percentage of abrasion resistance is reported. A complete report includes the aging conditions, conditioning history, test standard, apparatus type, force, abrasion distance, individual and mean volume losses, and the abrasion resistance index.

Applications

Combined aging and abrasion testing supports decision-making across many industries:

• Tire development and quality control, where tread wear retention after thermal and ozone aging is a key durability indicator.
• Automotive engineering, for wiper blades, bushings, engine mounts, and door seals exposed to heat, ozone, and fluids over a vehicle lifetime.
• Mining and bulk material handling, to specify conveyor belt cover compounds that retain wear resistance after years of exposure.
• Footwear manufacturing, to certify outsole wear performance after light and heat exposure during storage and retail display.
• Formulation research, to quantify the effectiveness of antiozonants, antioxidants, and reinforcing filler systems.
• Service-life prediction and warranty analysis, where accelerated aging results are extrapolated to field performance using time-temperature superposition and Arrhenius modeling.
• Regulatory compliance and supplier qualification, where accredited third-party laboratories provide independent verification against ISO, ASTM, EN, GB, and JIS requirements.

FAQ

Why must abrasion resistance be measured after aging instead of on new rubber?

Aging changes the hardness, crosslink density, and surface chemistry of rubber. Hardening from additional crosslinking or softening from chain scission alters how the material resists wear, so unaged abrasion data can significantly overestimate long-term durability. Testing aged specimens reveals the true retention of wear performance.

How is the aging condition selected?

The aging method should mirror the dominant field degradation mechanism: air oven aging for heat, ozone exposure for seals under strain, xenon-arc or UV weathering for outdoor products, and fluid immersion for parts contacting oils or fuels. Severity and duration are chosen to represent a meaningful fraction of the intended service life.

What is the abrasion resistance index and how is it interpreted?

The abrasion resistance index is the percentage ratio of the volume loss of a calibrated standard rubber to the volume loss of the test specimen measured under identical conditions. A value of 100 means the compound wears at the same rate as the reference; values above 100 indicate superior wear resistance, while values below 100 indicate poorer performance.

Which abrasion standard is most widely accepted?

ISO 4649, along with its equivalents ASTM D5963 and GB/T 9867, is the most widely specified method for the rotating cylindrical drum tester and is suitable for the majority of vulcanized thermoset rubbers and thermoplastic elastomers. ASTM D2228 and ASTM D3389 are selected when tread-wear correlation or flat-sheet testing is required.

What retention level is considered acceptable?

Acceptance criteria are product-specific and set by the purchaser or product standard. In many tire and industrial rubber specifications, compounds are expected to retain a substantial majority of their original abrasion resistance index after a defined aging exposure, with the exact threshold documented in technical agreements between supplier and customer.