BEHAVIOR OF THERMOPLASTIC POLYMERS DURING EXPLOSIVE DECOMPRESSIONS IN A PETROLEUM ENVIRONMENT

Thermoplastic polymers are used in the field of petroleum where they may encounter very severe conditions. So we are induced to study the ageing behaviour and the effect of rapid decompressions in a gaseous environment. In the latter case our aim is to define the limits of use and to identify the parameters influencing degradations. Such damaging is essentially of two types : (1) local in the form of blisters and (2) under extreme conditions, more homogeneous microscopic damage of the ''foaming'' type. Damage of the blistering type may threaten the integrity of the polymer part, and the microscopic damage does not necessarily affect the mechanical behaviour, for example the impact strength.