Relationships between processing conditions and mechanical properties of PA12 tubes

Jean-Marc Haudin (1) , Aurélien Carin (1) , Michel Vincent (1) , Nicolas Amouroux (2) , Gaëlle Bellet (2) , Fabrice Montezin (2)

1 CEMEF - Centre de Mise en Forme des Matériaux
2 CERDATO - Centre de recherche, développement, applications et technique de l'ouest

In polyamide 12 (PA12) tube extrusion, calibration is the key step of the process that affects the subsequent mechanical properties. In previous work it has been shown that according to the calibration conditions, a very oriented skin layer may be created, which has been correlated to an important decrease of elongation at break. In this paper, we present new results showing a good correlation between molecular orientation and fracture toughness, as evaluated by the EWF (Essential Work of Fracture) approach. They concern notched specimens and confirm the results obtained in classical tensile testing. EWF is very sensitive to processing conditions, and especially to induced orientation: it decreases from the external to the inner regions of the tube, and increases with skin orientation.

Mots clés: Polyamide 12; Tube extrusion; Calibration; Molecular orientation; Essential work of fracture

Domaines: Sciences de l'ingénieur [physics]; Matériaux

Jean-Marc Haudin, Aurélien Carin, Michel Vincent, Nicolas Amouroux, Gaëlle Bellet, et al.. Relationships between processing conditions and mechanical properties of PA12 tubes. Proceedings of the 12th ESAFORM Conference on Material Forming, Apr 2009, Enschede, France. pp.Pages 861-864, ⟨10.1007/s12289-009-0606-6⟩. ⟨hal-00509432⟩