# 2.2.3.5 UV Resistance and Stability Under UV Light

> From: LOCTITE®X Digital Manual for Bonding (https://www.loctitex.com/en/manuals/bonding/2.2.3.5-uv-resistance-and-stability-under-uv-light/)

##### 2.2.3.5 UV Resistance and Stability Under UV Light

UV radiation, which consists of photons with high energy relative to visible light, can cause degradation in the form of physical and chemical changes in materials. UV radiation will affect susceptible materials that are intended for use and storage outdoors and are, thus, exposed to sunlight.

Metals, which are good conductors of electricity and heat, also interfere with electromagnetic radiation. Metals are almost entirely unaffected by UV radiation and can therefore be considered impervious to UV degradation.

_Figure 43 Plastic degraded by exposure to UV radiation_

![Figure 43 Plastic degraded by exposure to UV radiation](/en/manuals/bonding/assets/img/ultraviolet-degradation-failure-plastic-uv-radiation.jpg)

_Figure 44 UV radiation from sunlight_

![Figure 44 UV radiation from sunlight](/en/manuals/bonding/assets/img/sunlight-radiation-uv-ultraviolet.jpg)

Polymers and elastomers are almost always electrical insulators and poor conductors of heat. Since most polymers and elastomers consist of covalently bonded organic constituents, most are susceptible to UV damage. The most prevalent type of UV damage to polymers and elastomers is breaking long chains into shorter ones through the direct action of high-energy photons.

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