UV Degradation Mechanisms
As mentioned on our other pages, photons within the UV spectrum possess relatively large amounts of energy due to their short wavelength. When these rays meet a material, this energy can be transfer to the molecules or atoms within the structure, having a range of possible effects.
Polymers such as plastics & rubbers, consist of long molecular chains. These can vary in length, complexity and oientation, and these factors all contribute to the overall material behaviour. Specific polymers possess specific chemical groups and bonds in their structure. Hence, Nylons are characterised by the amide linkage ( -CONH-). These different chemical groups absorb differing amounts of energy. Unfortunately most of these chemical groups have big absorbances within the UV spectrum. The diagram below demonstrates some of the typical chemical groups and their absorption energies.