[article]
| Titre : |
Polymères fondus et élastomères : aspects universels des relations non linéaires contrainte-déformation |
| Type de document : |
texte imprimé |
| Auteurs : |
M. H. Wagner, Auteur |
| Année de publication : |
1993 |
| Article en page(s) : |
p. 215-224 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Contraintes (mécanique)
Déformations (mécanique)
Elastomères
Rhéologie
|
| Index. décimale : |
668.9 Polymères |
| Résumé : |
A unifying strain measure for linear and branched polymer melts as well as for (crosslinked) rubbers is presented. It is shown that the relative tuve diameter and its inverse, the molecular stress function f, can be extracted directly for experimental data. The tension of the average network strand increases with increasing deformation. This is caused by an increasing restriction of lateral movement of polymer chains due to deformation. At small strains, f2 is found to be linear in the average stretch for melts as well as for rubbers, which corresponds to a constant volume on the tube. At large strains, melts show maximum molecular tension depending on the degree of long-chain branching, while rubbers show maximum extensibility.
In the case of rubbers, the influence of crosslink density on the strain measure is discussed. Chemical crosslinks and physical entanglements are indistinguishable with respect to their strain measure as long as the small-strain equilibrium modulus of the crosslinked plymer network is below the plateau modulus of the corresponding uncrosslinked polymer melt. Higher crosslink densities result in the classical contribution to the strain measure which reflects phantom chain behaviour. This can be rationalized by considering that short network strands with length scale below the entanglement spacing (or tube diameter) are not restricted by neighboring chains. |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5834 |
in LES CAHIERS DE RHEOLOGIE > Vol. XI, N° 3-4 (10/1993) . - p. 215-224
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Polymères fondus et élastomères : aspects universels des relations non linéaires contrainte-déformation in LES CAHIERS DE RHEOLOGIE, Vol. XI, N° 3-4 (10/1993)
