THE APPLICATION OF MIXED-CRYSTAL IR SPECTROSCOPY TO MOLECULAR DEFORMATION IN POLYETHYLENE BY ROLLING

The mixed crystal i.r. technique has been applied to polyethylene sing le crystal mats after rolling at room temperature to roll ratios up to 6.0. Reduction in the absorbance of the outer CD2 bending components provides evidence of lamellar breakup. Model calculations indicate tha t the size of blocks which break away from the crystals is reduced to approximately 36 angstrom for a ratio of 6, while X-ray diffraction da ta show that crystallite reorientation occurs progressively with incre asing roll ratio. Changes in small-angle X-ray scattering and the Rama n longitudinal acoustic mode with rolling demonstrate that crystallite stacking periodicity is gradually lost and that crystal thickness rem ains unchanged.