Dynamic Fracture of a Semi-Crystalline Bio-Based Polymer Pipe: Effect of Temperature

Abstract

The influence of temperature on the resistance to rapid crack propagation of a semi-crystalline bio-based polymer was studied. The experimental results described in this study allow to initiate a first discussion on the role of viscos-ity and its link with the fracture behaviour and a heterogeneous microstruc-ture such as the semi-crysalline polymer. Dynamic fracture tests on pipes were carried out. It would appear that a temperature decrease of approx-imately 40 ̊C relative to ambient has no significant influence on the average crack propagation velocity (≈0.6cR), fracture energy and surface roughness. On the contrary, crack propagation paths seem to vary with temperature. The difference in fracture behaviour between the amorphous and crystalline phase varies significantly as a function of temperature. The difference between the initiation resistance and the rapid propagation also varies. This difference seems to be significantly reduced by lowering the temperature. The mechan-isms of cavitation damage and plastic flow are increasingly limited by the de-crease in temperature (and therefore in macromolecular mobility). Crack propagation in the pipe is more extensive and therefore more critical. This is emphasised in particular by the probability of the material to be macro-branched as the temperature decreases.