2. Influence of forming conditions on crystallization

2.1 Influence of flow

The flow of molten polymer has a major influence on the development of morphologies in processes. Its intensity is initially expressed in terms of process parameters such as drawing speed and injection rate. However, it is more relevant to translate forming conditions into quantities from continuum mechanics: strain rates, deformations, stresses, and even specific energy received by the material (in J/m ³ ). Among these, shear (shear rate) and elongation (elongation rate) strain rates are widely used, as shear and elongation are the reference flows, both in the laboratory and in processes.

We distinguish between :

• processes involving flow followed...