Study of the leacril dyeing process by a cationic dye from an emulsion system

Adsorption studies of a cationic dye, Rhodamine B, from an emulsion phase o n Leacril fabric at different temperatures were conducted. The emulsion pha se consisted of n-hexadecane emulsified by isopropyl alcohol(1 M) and stabi lized by tannic acid. In the alcohol solution Rhodamine B was dissolved. Th e kinetics of its adsorption and desorption is discussed. The changes in Le acril surface free energy components in the dyeing process were also determ ined. The adsorption data show that the presence of an emulsion increases t he dye adsorption at room temperature (293 K) and at 313 K, while at 333 K it is smaller than that from Rhodamine solution alone. However, Rhodamine d esorbs more when adsorbed from the solution. Surface free energy components differ for the Leacril samples dyed at different temperatures, and the mos t hydrophobic surface was obtained for the samples dyed at 333 K, where the electron-donor component is the lowest one. In general, the work of water spreading is close to zero, except for the above sample for which it is rel atively highly negative. Possible mechanisms of the dye adsorption are disc ussed. (C) 2001 Academic Press.