EQUILIBRIUM SORPTION OF DISPERSE DYE IN POLYETHYLENE FILMS TREATED WITH ORGANIC SOLVENTS

Abstract

High density polyethylene (PE) films were treated with dimethylacetamide (DMAc) and xylene at various temperatures. These films were dyed with C. I. Disperse Yellow 7 (Y-7) at 80°C. The equilibrium sorption (M_o) of Y-7 by the films increased with increasing their volume crystallinity (C_v). The M_o values for the films treated with xylene having a strong solvation to PE were much larger than those for the films treated with DMAc in the whole range of C_v. The changes in M_o for both systems were analyzed in terms of a mosaic block structural model; the increase in M_o, was attributable to enhanced sorption in amorphous side region located parallel to the molecular axis between crystalline cores by the solvent treatment. A long rodlike dye molecule of Y-7 seems to be easily absorbed on the amorphous chain having an extended chain conformation in this region from which lower molecular-weight fractions are extracted by the solvents.