Mobility and orientation of amorphous chains in cold drawn films of isotactic polypropylene (PP) are studied by 2H-NMR as a function of the annealing temperature. It is shown that the deformation is not affine. The relaxation of amorphous chains in materials annealed with free and clamped ends appears respectively at T* < Tg 1 508C and at Tac < 808C. Above these transition temperatures, corresponding to the onset of the chain mobility in the amorphous and crystalline states, the orientation of amorphous chains decreases linearly with the temperature. These reports show that the 2H-NMR technique provides important information on the plastic deformation of semi-crystalline polymers.
Посилання на статтю:
Polymer Communication Mobility and relaxation of amorphous chains in drawn polypropylene: 2 H-NMR study / M. Botev, R. Neffati, J. Rault // Polymer. – 1999. – N 40. – P. 5227–5232.