The Unseen Damage of the Sun

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Nowadays, everyone is aware of the damage that the sun can cause to the skin, such as cancer. 

Sunscreens are applied to block the sun's ultraviolet (UV) rays before they penetrate the skin. Some creams form a physical sunscreen that reflects UV rays, while others create a chemical sunscreen that absorbs UV rays.

But what are UV rays? They refer to a type of electromagnetic radiation with wavelengths shorter than visible light but longer than X-rays. UV rays are divided into three main categories:

  • UVA (320-400 nm): Constitute the majority of the sun's natural light, representing about 95% of the UV rays that reach the Earth's surface.
  • UVB (280-320 nm): Very few reach the Earth's surface as they are mostly absorbed by the atmosphere, particularly the ozone layer.
  • UVC (100-280 nm): Never reach the Earth's surface because they are filtered out by the atmosphere.

But did you know that UV rays do not only affect our skin?

Indeed, UV rays mainly affect organic materials but can also influence some inorganic materials. UV degradation refers to the changes and deterioration that materials undergo when exposed to UV rays. UV rays can cause the degradation of pigments and dyes, leading to colour loss, bleaching, or yellowing of materials. They can break polymer chains, making materials more brittle and less elastic.

Accelerated aging tests measure how materials behave under prolonged exposure to sunlight, helping to develop more durable and resistant products. These tests are carried out in special chambers, such as Innofibre's Q-SUN chamber (Figure 1), where samples are exposed to UV lamps that simulate sunlight. Test conditions often include cycles of humidity and temperature to mimic outdoor conditions.

innofibre2 23jan25 2Figure 1: Q-SUN Accelerated Aging Chamber 

Using an accelerated aging chamber offers several advantages to industries seeking to ensure the quality and durability of their products. Accelerated aging tests can simulate several years of degradation in just a few days or weeks, which is crucial for the rapid development of new products. They help predict the lifespan and performance of materials and products under various environmental conditions, such as light, heat, humidity, and some corrosive agents.

By identifying weaknesses or defects in products before they reach the market, manufacturers can improve the quality and reliability of their products. Detecting potential aging and degradation issues early in the development cycle can avoid the high costs associated with product recalls or warranty claims. Many industries, such as automotive, electronics, and building materials, must comply with specific durability standards such as ISO, ASTM, AATCC, GB/T, etc. Accelerated aging testing helps ensure that products meet these standards.

Accelerated aging tests also demonstrate the reliability of products compared to competitors. In research and development, they allow the study of degradation mechanisms and the finding of ways to improve material formulations, coatings, and manufacturing methods to increase resistance to aging. For example, in a research project at Innofibre, the aging chamber was used to evaluate the impact of UV on the colour stability of paper when a percentage of microalgae biomass was added to the pulp (Figure 2).

 innofibre2 23jan25 1Figure 2: Colour Degradation Tests of Microalgae Added to the Pulp

In summary, accelerated aging chambers are essential tools to ensure the robustness, reliability, and durability of products while enabling companies to meet tight development deadlines and regulatory requirements.


Innofibre Mission

"Contribute to the technological positioning and sustainable development of the paper and biorefining industry, by supporting the innovation and diversification of products derived from biomass and by adapting papermaking technologies."

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Caroline Lachance
Caroline Lachance
Technician, Innofibre