BEHAVIOR OF THERMOPLASTIC POLYMERS DURING EXPLOSIVE DECOMPRESSIONS INA PETROLEUM ENVIRONMENT

Thermoplastic polymers are used in the field of petroleum where they m ay encounter very severe conditions. So we are induced to study the ag eing behaviour and the effect of rapid decompressions in a gaseous env ironment. In the latter case our aim is to define the limits of use an d to identify the parameters influencing degradations. Such damaging i s 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 integ rity of the polymer part, and the microscopic damage does not necessar ily affect the mechanical behaviour, for example the impact strength.