INFLUENCE OF METAL-IONS ON STRUCTURE AND PROPERTIES OF ACRYLIC FIBERS

The acrylic fibers containing 10.8 wt % of acrylic acid as a comonomer were treated with 5% aqueous solution of sulphates of alkali metals ( sodium and potassium) and transition metals (cobalt and nickel) at 90 degrees C for 5 min. The effect of this treatment on the chemical stru cture, thermal behavior and mechanical properties of this fiber was in vestigated through FTIR, X-ray, DSC, and TGA techniques. The changes i n the chemical structure of the fibers have been noticed as a change i n the intensity of characteristic infrared absorption bands. Broadenin g of the absorption band at 1700 cm(-1) due to COO- stretch is also no ticed in the case of fibers treated with salts of alkali metals, proba bly because of formation of a COO-M+ structure. WAXD studies of the fi bers treated with metal salts showed the decrease in the crystallinity of the treated fibers. DSC curves of metalated fibers showed the onse t of exothermic cyclization at a higher temperature. The initial modul us of the samples increased after this treatment. The fibers treated w ith sulphates of alkali metals showed an approximately twofold increas e in elongation at break compared to the untreated ones. (C) 1998 John Wiley & Sons, Inc.