Sorption Properties of Dispersed Dye in Drawn Polyethylene as a Function of Molecular Orientation in Amorphous Phase

Abstract

The equilibrium amount and the rate of adsorption of a dispersed dye, Whitex were measured at 80°C for linear polyethylene(PE) films to discuss the correlation between the sorption properties and the molecular orientation in the amorphous regions.The PE specimens which were drawn at 60°C in various draw ratios ranging from 1.0 to 10.0 were prepared for the subsequent dyeing.In the comparatively earlier stage of the sorption, the rate of adsorption of Whitex obeyed Fick's law to result in the diffusion constant D. The diffusion constant D dropped remarkably with draw ratios, whereas the amount of equilibrium sorption Q∞increased monotonically.These results were explained in terms of the following two points of view: 1 the increase in the energy of amorphous regions with molecular orientation and 2 the decrease in the free volume and the increase in voids with drawing.