The ageing of polymers usually results in a reduction of material properties such as mechanical characteristic values. Typically, the quality of the surfaces may decrease since micro crazes are formed and some materials tend to fading, change of colour and chalking. The ageing of polymers can lead to premature malfunctioning of components. Appropriate measures should be taken to avoid damage caused by ageing.
The ageing of polymers is influenced by numerous conditions such as the impacting medium, the temperature and solar radiation. Because of a combined exposure to temperature and medium, ageing is a very complex issue for polymers.
To investigate certain influencing factors of ageing, numerous methods have been developed. These can be assigned to different subject areas:
In addition to these subject areas, we offer the use of the Stepped Isothermal Method (SIM). This accelerated test is used to evaluate long-term creep behaviour. As an example, the tensile test for the global and the registered macro hardness measurement is carried out for the surface-sensitive determination of the long-term creep behaviour.
For the investigation of ageing, the selection of special and appropriate studies for the characterisation of various ageing phenomenon is very important. Apart from optical and microscopic considerations, measurements of colour and gloss quantify the changes on the surfaces. Appropriate mechanical tests to evaluate the changes of the intrinsic and global material characteristics have to be chosen especially. Structure analyses can give information about the degradation of molecular chains and stabilisers.