Expertise Degradation and Stabilization of Polymeric Materials:
When polymeric materials are exposed to shear stress, heat, light, air, water, radiation or mechanical loading, chemical reactions are initiated that lead to chemical changes that might result in undesired changes (degradation) in appearance (e.g. gloss, texture and colour) and mechanical properties (e.g. tensile, flexural or impact strength).
The terminologies used to describe the type of degradation are related to the environment to which the plastic is exposed:
- During processing thermoplastic polymers are exposed to harsh environments. Temperatures are relatively high (above the melting or glass transition temperature of the polymeric material), in many cases a lot of shear is involved and although the majority of processing equipment is closed, oxygen and water can play an important role too.
- Although in their application polymeric materials are exposed to a less harsh environment, the period they exposed are much longer. The type of in-service degradation depends on the environment to which the plastic is exposed to.
- For outdoor applications, sunlight plays an important role. This type of degradation is defined as UV-degradation or outdoor durability
- If sunlight does not play an important role, such as in under the hood applications and in geotextiles, plastics degrade too. This type of degradation is called thermo-oxidative degradation or long-term heat stability
To make it possible to process polymeric materials and to make them useful for the above mentioned applications, most polymeric materials need to be protected. This is done by adding different stabilizers types, which an important part of my expertise