Читать книгу The Rheology Handbook - Thomas Mezger - Страница 244

The observed macromolecule reacts to the constant shear stress showing slow, creeping motion. Forced by the constant load, the spherical coil begins to leave its state of rest exhibiting increasing deformation. It changes more and more to the shape of an ellipsoid whose axis is oriented lengthways between the shear direction and the direction of the shear gradient. More illustrative: An ellipsoid is shaped “like an American football”. As a consequence, deformation is increasing now as well of the individual molecule, as well as of the superstructure of the whole polymer sample due to the entanglements between the molecule chains.