Polymer, Vol.40, No.10, 2631-2637, 1999
Influence of orientation and irradiation on stress relaxation of linear low-density polyethylene (LLDPE): a two-process model
Change in the stress relaxation behavior of linear low-density polyethylene (LLDPE) with drawing and irradiation has been investigated. Samples of isotropic LLDPE were oriented to draw ratios lambda = 6,9,11 and irradiated to integral doses between 35 and 500 kGy. Stress relaxation was interpreted in terms of a two-process model, first associated with the crystal and second with the amorphous fraction. Analyses of viscoelastic properties of these two fractions have revealed their different behavior upon drawing and irradiation.