Chemical Modifcation of Cellulosic Fibers to improve Fixation of Rea Ctivedyes

Abstract

The modification of cotton cellulose by chemical treatment was studied. The study was aimed to dye cotton fabric in the absence of alkali. The principle method of modification was to incorporate a free amino group into cellulose backbone. The modifying agent, DCPT, was prepared by the reaction between cyanuric chloride and pyridine. Spectroscopic techniques including FTIR and 13C-NMR and chromatography were employed to characterize the chemical structure of DCPT. The application methods such as exhaustion and pad-batch were used to modify cotton fabric with DCPT. Further treatment of the DCPT cotton with suitable amines was carried out in order to achieve the reactive fiber which was then dyed with commercial reactive dyes by exhaust and thermofix dyeings without the requirement of alkali. The dyeing results showed that the dye fixation value of modified cotton fabric which was modified using exhaustion method and then dyed also using exhaust dyeing was significantly higher than those obtained from the conventional dyeing method. However, in any case of modification, thermofix dyeing of modified cotton fabric gave unsatisfactory results partly due to inefficient contact between dye molecules and reactive sites on modified cotton fabric.