Dependence of the structure of uncrystallized regions of polyethylene on the draw ratio

Abstract

Paramagnetic resonance and X-ray diffraction at small and large angles have been used to investigate the structure of non-crystalline (amorphous) regions of HPPE in specimens that had been drawn to various draw ratios. The distribution function with respect to length in the amorphous interlayer is complex. As the draw ratio is increased, the maximum in the distribution is displaced towards chains of shorter length (that is, when fully extended) and it becomes more intense. An increase in the proportion of such “tie” chains in the amorphous interlayers explains the increase in the polymer's strength with an increase in draw ratio.