Chemical and gamma irradiation treatment of polyamide fabrics with some crosslinking agents followed by dyeing

The purpose of this investigation was to improve the dyeability of polyamides (nylon-6) fabrics towards some direct dyes through chemical bonds between the direct dye and the nylon chains.Specific direct dyes that contain in their molecular structure at least one free amino group I>’ere chosen viz.; Benzamine Bordeaux FB, Benzopurpurine 10 B,SolJphenyle Orange TGL, and Helion Green 5 GL.In order to form such chemical bonds between the dye and the nylon end groups a highly reactive compound viz., 1,3,5-trichlorotriazine (cyanuric chloride) was selected as crosslinking agent This intermediate compound is believed to react with poly-amide under appropriate conditions through replacement with one or two chlorine atoms. In a next step, the polyamidetreated with cyanuric chloride was allowed to be dyed with the selective direct dyes to form a relatively strong chemi-cal bond.In order to investigate the effect of gamma irradia- tion on such chemical reactions, the above treatments were carried out on unirradiated nylon and after exposure to dif- ferent radiation doses.Furthermore, different factors including cyanuric chlo- ride concentratIon, temperature of dyeing, time of dyeing, henzoic acid concentration and the pH were considered to examine the effect of such factors on the dye fixation after treatments. In addition, the effect of different solvents viz., hutanol, Dioxane and perchloroethylene on the dyefixation has been investigated. The influence of solventson dye fixation was studied on the basis that these solvents act as plasticizers in nolyamides and thus affect the glass transition temperature By knowing the dyeing temperature (Td) in presence of the above solvents a practical relation- ship between the dyeing temperature Td and glass transition temperature Tg could be arised.