Hysteretic thermal behavior of amorphous semi-aromatic polyamides

• Published in: Polymer (Guilford) Vol. 46; no. 25; pp. 11870 - 11875
• Main Authors: Moisa, S., Landsberg, G., Rittel, D., Halary, J.L.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 28.11.2005; Elsevier
• Subjects: Applied sciences; Cyclic loading; Exact sciences and technology; Hysteretic heating; Mechanical properties; Organic polymers; Physicochemistry of polymers; Plastic deformation; Properties and characterization; Cyclic loading; Hysteretic heating; Plastic deformation; Strain rate sensitivity; Stress strain relation; Mechanical properties; Experimental study; Amide 12 copolymer; Amorphous copolymer; Compressive stress; Tensile stress; Thermal hysteresis; Amide copolymer; Cyclic load; Heating up
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2005.10.062

The hysteretic thermal behavior of two amorphous semi-aromatic polyamides, subjected to cyclic loading at high stress levels, has been investigated. The two polymers, called 1I and 1.8T, were selected with regards to chain mobility and plastic deformability considerations. This work reports the exothermal response of these materials to high level cyclic stress (of the order of σ y), with emphasis on the initial thermal peak, normally observed in commercial polycarbonate (PC) and not in commercial polymethylmethacrylate (PMMA). The investigated materials exhibit noticeable initial thermal peaks, which are similar, to some extent, to those observed in PC. The present results suggest that chain mobility may indeed be partially responsible for the initial exothermal peak, thus supporting the hypothesis that it may be related to the transition from shear deformation zones to chain disentanglement crazing.