Mixed Crystal Infrared Spectroscopy of Uniaxially Drawn Polyethylene Films

Abstract

Blends of fully deuterated polyethylene with unlabeled polymer have been studied using Fourier transform infrared (FT-IR) spectroscopy. Melt quenched samples were drawn at 1 mm min−1, clamped, and cooled with liquid nitrogen. The CD2 bending vibration is sensitive to the local molecular arrangement. Changes in band components were related to (1) crystallization of amorphous polymer; (2) the untwisting of spherulite ribbons perpendicular to the draw direction; and (3) coarse slip. Measurement of remaining doublet splittings enabled estimates of surviving crystallite block sizes to be made. In addition, CH2 wagging and rocking bands showed evidence of increasingly defective crystals and of a Martensitic transformation to the monoclinic crystal form.