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

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 T _g of these four fibers was investigated by analyzing the DSC heating curves from 50° to 150°C for fiber/water mixtures. T _g 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 T _g models are presented for describing the dye diffusion into porous and less porous acrylic fibers from aqueous dyebath.