E.p.r. study of the orientation of polymer segments induced by cold drawing of a low density polyethylene

Abstract The orientation of low density polyethylene (LDPE) chain segments induced by cold drawing was determined by electron paramagnetic resonance spectra measured for samples probed by tempyl stearate or alkyl radicals formed by γ-irradiation. We characterized the induced orientation in the amorphous phase using a two-dimensional Gaussian distribution function ( σ = 12°), axially symmetrical about the draw direction. A simultaneously induced alignment of the crystallite c -axes with the draw direction, accompanied by a random orientation of the crystallite a -axes and b -axes, was also observed. We propose that the molecular morphology of cold-drawn LDPE can be described in terms of specifically oriented crystallites emanating chain segments packed in the condis state.