par Bauwens, Jean Claude 
Référence Plastics, Rubber and Composites Processing and Applications, 18, 3, page (149-153)
Publication Publié, 1992
Référence Plastics, Rubber and Composites Processing and Applications, 18, 3, page (149-153)
Publication Publié, 1992
Article révisé par les pairs
| Résumé : | A recent model which was found useful to account for the creep curve of polycarbonate is applied here to the loss curve of this polymer in the α transition range. The deformation behaviour is approached in a twofold manner: an analytical model and a ladder mechanical model both accounting for rejuvenation effects at high strains. The expression of the loss tangent is derived here resulting in a power law of the viscosity with an exponent equal to - 1/3. The viscosity itself is expressed as a function of the temperature Θ characterizing the structural state of the sample. The loss curves obtained on heating the sample at constant frequency up to Tg exhibit a plateau on the left side of the α peak which is attributed to a Θ decrease during the measurements; heating the sample in this temperature range includes an involuntary thermal treatment. The loss curve is rather well modelled here, so the proposed approach seems to be suitable at small strains when the structural state is affected by heating as well as under high stress when the structural state is affected by deformation. |
