Organic materials such as plastics, inks and paints are often damaged by exposure to light and weathering. This is the main reason why accelerated weatherability and light stability Testers are widely used in material certification, quality control as well as research and development. The results produced by these Testers are often repeatable and fast. Xenon arc Test Chambers and fluorescent UV (QUV) accelerated weathering Testers are some of the commonly used accelerated weathering Testers. However, although they are commonly used Testers, they are based on different approaches.
The xenon Test Chamber is designed in such a way that it reproduces the entire spectrum of sunlight including infrared (IR), ultraviolet (UV) and visible light. A xenon arc is basically an attempt to reproduce sunlight from 295 nm to 800 nm. When it comes to QUV, it just reproduces the damaging effects of sunlight that occurs from 300 nm -400 nm. This particular Tester is based on the concept that durable materials exposed outdoors suffer the most weathering damage from short-wave UV rays.
QUV aging Tester
The Tester is designed in such a way that, through the use of fluorescent UV lamps, the damaging effects normally caused by sunlight on durable materials can be reproduced. The coating on the glass tube is engineered so that the tube produces primarily UV light rather than mid-range or visible light.
Various types of lamps with different spectra exist for various exposure applications. UVA-340 lamps can provide a good simulation of sunlight in the important short-wave UV region. UV-B lights are also often used in this Tester and they cause faster degradation than UV-A lights.
The main benefit of using the QUV is that it provides the most realistic simulation of outdoor moisture intrusion as it uses a unique condensation mechanism to reproduce outdoor moisture. This is the most widely used weather Tester in the universe, as it excites the damaging effects of dew, rain and sun.
Xenon Test Chamber
The fact that xenon arc Testers generate energy in the visible, infrared, and ultraviolet regions makes them considered a good simulation of full-spectrum sunlight. The xenon arc spectrum needs to be filtered so that natural sunlight can be simulated. These filters act to reduce harmful radiation or/and heat. There are different types of different glass filters with the ability to obtain different spectra. The main factors in determining the filter to use include the materials tested and the end use. Different types of filters allow different amounts of short-wave UV, which can seriously affect the type and rate of degradation.
Most xenon arc Testers typically use humidity control and/or water spray systems to simulate the effects of moisture. A xenon chamber sprays water onto the specimen to simulate the effects of outdoor humidity. This particular method is particularly desirable for simulating the effects of mechanical corrosion or thermal shock. These Testers usually have systems to control relative humidity, temperature and light intensity (irradiance).
