SynopsisComparison of the various solubility parameters of different plasticizing agents has shown that their plasticizing action on Acrilan filaments is governed by polar interactions. The diameter swelling of the filaments appears to decrease with increasing efficiency of the plasticizing agent. The diffusion of a disperse dye through the plasticized fiber is not related to the fiber swelling and is controlled by the plasticizing action of the dyebath.

The mechanism of the solvent–assisted dyeing of acrylic fibres using benzyl alcohol has been investigated. The carrier action of benzyl alcohol plays a major role in increasing the rate of dyeing.

The dyeing of Acrilan with C.I. Basic Green 4 from water containing benzyl alcohol and benzyl alcohol containing water has been examined. Benzyl alcohol in water acts as a plasticizing agent for the fibre. The plasticizing action of small quantities of water in benzyl alcohol has also been detected and in both systems the rate of diffusion of dye into the fibre is related to the plasticizing action. The equilibrium absorption is a function of the difference between the dyeing temperature (T) and the glass transition temperature (Tg) of the fibre. The differences in the behaviour of the dye in the aqueous and benzyl alcohol dyebaths are related to the degree of dissociation of the dye and the mechanical properties of the fibres.

The adsorption of iodine and bromine by polyethylene sulfide‐containing fabrics was investigated. It was found that the halogens could be adsorbed from aqueous solution as well as from a saturated halogen atmosphere. Adsorption was attributed to complexation by the sulfide bonds in the polymer. Adsorption from aqueous solution led to the formation of a complex with a molar ratio of halogen molecules (X2) to ethylene sulfide units of 1:1, while that from gaseous iodine a ratio of 2 was obtained. Complexation was accompanied by a little degradation of the polysulfide which was attributed to halogenation of the polyethylene sulfide. High adsorption of bromine led to complete degradation of the cotton fabric due to oxidation of the cellulose. The adsorption of polyethylene sulfide in the fabric was much higher than that of homopolyethylene sulfide itself under comparable conditions.

Measurements have been made which show that there is no predictable connection between fibre swelling and the plasticisation of acrylic fibres. The diffusion of dyes into the fibres is controlled by the segmental mobility of the fibrous polymer chains and not by fibre swelling.