Abstract
Mobility and orientation of amorphous chains in cold drawn films of isotactic polypropylene (PP) are studied by H-2-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* approximate to T-g + 50 degrees C and at T alpha(c) = 80 degrees C. 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 H-2-NMR technique provides important information on the plastic deformation of semi-crystalline polymers. (C) 1999 Elsevier Science Ltd. All rights reserved.