Rubber aging

Sooner or later, almost everything falls apart – even tough Trelleborg hoses. If left to bake in the sun, the polymers we use in our hoses and other products begin to crack, fade or discolor and lose their elasticity.

Hose with typical ageing cracks

To learn more about the rate at which this aging happens and gather clues about how to slow it down, Trelleborg researchers have conducted a number of in-depth studies on the impact of energy (either thermal or photochemical) on the polymers we use in our products, including NBR and EPDM.
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Suntest XLS + chamber & SEPAP 12/24 Tests

Trelleborg scientists have aged hose polymers in two ways:  

  • A SUNTEST XLS + chamber, which reproduces irradiating solar light with a filtered Xenon lamp, as well as controlling temperature and humidity, and
  • A SEPAP 12/24 type enclosure, which uses mercury vapor lamps that emit light non-continuously across a spectrum, mimicking the patterns of natural light. 
 
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SUNTEST XLS + chamber

SEPAP

SEPAP 12/24

UV spectroscopy 

In the case of the NBR experiment, although Trelleborg scientists could see that the polymer was degrading because it had turned yellow, to find more precise results, they tested the samples in a UV-visible spectroscope and an infrared spectroscope.
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Another example of discoloration on an EPDM sample; the left part was protected from UV radiation.''

FTIR spectrum of NBR under different exposure durations

When NBR breaks down in the presence of oxygen or UV light, oxidation products appear. Under an infrared spectroscope, these products form characteristic bands in the area between 1800 and 1650 cm-1. The thicker the bands, the more degradation has occurred.

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Comparative test between initial vs improved compound

After identifying this degradation marker, researchers followed its evolution in the SEPAP.

From there, they can compare the improvement reached from an initial NBR sample and a better stabilized formulation. In this research, Trelleborg has increased the lifespan of the hose by a factor 3!

Exposure duration

Our team of chemist estimated that for NBR, one month in the SEPAP enclosure corresponds to one year outdoors in our local climate.
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The team’s next step:

Develop a chemical stabilization strategy that will limit the impact of radiation or other factors on the aging of the material.

“We hope to triple the amount of radiation that a material like NBR can take without compromising the strength of a major physical property of the material, such as resistance to abrasion,” said Gérald Soulagnet, head of Material Development Department at Trelleborg Industrial hose.

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