Studies on Single Crystals of Polyvinyl Alcohol

IV. Fracture of Single Crystals

Abstract

Polyvinyl alcohol (PVA) single crystals fractured by ultrasonic irradiation or by using a mortar are examined by electron microscope and X-ray diffraction. The X-ray patterns from fractured single crystals exhibit an increase in the half-widths. The absorption of Congo red or iodine on fractured single crystals is larger than that on unfractured crystals. Single crystals drawn on PVA film break along lines parallel to the corrugations. Further, single crystals deposited on a carbon coated grid are deformed by bending the grid to an appropriate curvature. Single crystals either break or are converted into fibers in which the b-axes are parallel to the axis of stretching.