Changes in structural and mechanical behaviour of PVDF with processing or thermal treatment.: 2. Evolution of mechanical behaviour

The following study is the continuation of our previous work, which consisted in analysing the structural evolution of PVDF after different thermomechanical treatments. In this second part, we will discuss the influence of these evolutions on the mechanical behaviour. This has been determined by tensile drawing, creep or dynamic measurements.The observed changes in behaviour are strongly influenced by the different processing routes. Therefore, the beta conformation appears only when stretching injection-moulded samples (IM) and is accompanied by an increase of rupture stress compared to yield stress, which is not the case for compressed samples (CM). The influence of annealing on mechanical behaviour varies with annealing and measurement temperature. Thus, annealing at 80°C after standardisation increases the Youngʹs modulus at 120°C and decreases it during drawing at 23°C compared to other annealing treatments.