Ageing, degradation and creep studies

In the majority of cases, polymers in service will encounter both heat and oxygen. It is the norm therefore that these materials will undergo oxidative thermal decomposition and 

The chemical changes that can occur in a rubber or plastic when it undergoes oxidative thermal degradation can vary according to the particular polymer concerned. There are two principal mechanisms involved  

In reality, both of these mechanisms are usually present, but one will predominate over the other and this is determined by the chemical structure of the polymer backbone and the availability of hydrogen (or other reactive species) for the free radicals to react with. Once a free radical has formed on the polymer molecule by hydrogen abstraction (a typical route in oxidative degradation), it becomes stable either by a rearrangement reaction (often leading to chain scission) or by reacting with another radical (cross-link formation). 

In amorphous plastics, ageing will be apparent by a narrowing of the tan 8 peak associated with the 7 of the material. Chemical ageing has been discussed above, but physical ageing. 

AL0047 rubber sample F7B new Scales not UKAS calibrated 

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