Additives
UV Stabilizers(UV)
The service life of polymers is limited by their degradation. Degradation can be caused by a number of environmental factors, e.g. temperature, humidity, impurities, mechanical load, irradiation, microorganisms, chemicals and air.
Light stabilizers/UV absorbers combat the degradation that polymers can undergo under the effects of:
- Sunlight
- UV rays
- Heat
- Reaction with oxygen
Effects of UV degradation on polymers may be assessed from the following factors:
- Change in chemical structure
- Change on surface
- Embrittlement
- Generation of free radicals
- Change in molecular weight
- Loss in mechanical properties
- Impairment of transparency
Addition of light stabilizers/UV absorbers can extend the life and hence, improve the appearance of the plastic. Selection of a light stabilizer / UV absorber largely depends upon the substrate to be protected, its envisioned functional life and its sensitivity to photodegradation.
- The most commonly used light stabilizers in plastics are Hindered Amine Light Stabilizers (HALS).
- The most common UV absorbers are benzotriazoles, benzophenones and organic nickel compounds.
