Change of Water States in Acrylic Fibers and Their Glass Transition Temperatures by DSC Measurements

Abstract

DSC measurements of four kinds of acrylic fibers (Dralon X-100, Dunova, Acryl, and Aqualon) were made after equilibration with various amounts of water. The DSC curves in heating from -80° to 20°C were analyzed to obtain information on the state of water in these fibers. The results show that in a water-saturated state, the porous fibers Dunova and Aqualon contain much more free water than the less porous fibers Dralon X-100 and Acryl, while all four fibers contain relatively small amounts of bound water. The effect of water content on the glass transition temperatures Tg of these four fibers was investigated by analyzing the DSC heating curves from 50° to 150°C for fiber/water mixtures. Tg decreases with increasing water content and approaches an almost constant value for all four fibers. Considering the results on the change of water states and the change of Tg models are presented for describing the dye diffusion into porous and less porous acrylic fibers from aqueous dyebath.