STUDIES ON THE DYEING PROPERTIES OF NYLON 6 FIBER

(1) THE INVESTIGATION ON THE ADSOBPTION OF THREE KIND OF NYLON FIBERS WHICH INCLUDE DIFFERENT AMINO END GROUP

Abstract

The adsorption of dye (1) (Acid Red 18) and dye (2) (Direct Blue 71) on to Nylon 6 fiber in equilibrium under different pH range of dye solution was investigated.
Above mentioned Nylon 6 fibers consist of three kind of fibers which include 9.5×10^-5 mol, 5.4×10^-5 mol and 2.5×10^-5 mol of amino end group per lgram of fiber respectively.
The dyeing was carried out at 90°C and at 2.0_??_10.5 pH value.
The following resulted; The adsorption of dye (1) and dye (2) onto Nylon6 fibers is dependent on the amount of amino end group, but the degree of adsorption of dye (1) is different from dye (2). In the former the degree is larger than that of the latter and the adsorption of dye (1) is nearly equal to the content of amino end group, on the other hand the adsorption of dye (2) had far low equilibrium value.
Isotherm of dye (1) showed a typical Langmuir's curve and that of dye (2) showed H-type curve at pH value 3.5
These facts may be explained as follows; the nonpolar force contributed to the dyeing mechanism of dye (2) to the main part of the adsorption of dye (1) is attributable to the salt-linkage and that of dye (2) is to the hydrogen bond orvan der Waal's force.
But it is not clear that the reason for low adsorption of dye (2) is due to a large molecular weight or not.