Young's modulus and β-relaxation of amorphous polymers
Résumé
The mechanical behaviour of polymers have been studied as a function of time and temperature. The influence of a critical temperature or critical strain rate have been pointed out which may be related to relaxation phenomena. This study, carried out on Poly Methyl Methacrylate, shows that this relaxation phenomena can be associated to the β-relaxation. When the process does not occur, for very low rate of strain at low strain rate (the higher the strain rate, the higher the rate of strain), the behaviour of P.M.M.A. is independent of the strain rate and the strain is proportional to the applied stress. When the β relaxation can occur the deformation is no more linear, and is highly dependent on strain rate and plasticity is due to diffusionnal mechanism.
Domaines
Articles anciensOrigine | Accord explicite pour ce dépôt |
---|