Azide Reactive Dyes Part II ‐ Transfer‐printing Properties of Sulphonyl‐ and Aryl‐azide Dyes on Nylon 6.6

Abstract

e d s LS2 9JTThe transfer-printing properties of dyes containing the sulphonylazide (-SO2 N3) and arylazide (ArN3) groups have been examined for nylon 6.6 substrates. After sublimation at 200°C the azide group decomposes rapidly to a nitrene species which reacts with the polymer. Dye fixation occurs by insertion of the nitrene into the carbon-hydrogen bonds of the polymer, thus forming a nitrogen bridge. A competing reaction involves hydrogen abstraction from the substrate to give an amino derivative of the dye which is not covalently bound to the polymer. Fibre-grafting occurs to the extent of about 60-75% for both series of dyes. Unlike the sulphonylazides, the arylazide dyes show a pronounced colour change after transfer, as the thermallv-generated amino group is directly conjugated with the dye chromogen.

Synthesis and photophysics of a series of lipophilic phosphazene‐based fluorescent indicators

“…MeCN was the solvent of choice for several reasons. First, it is a weakly basic dipolar aprotic solvent with a high relative permittivity (ε r = 36.0) and hence favors the dissociation of ion pairs into free ions. Also, a very low autoprotolysis constant (p K auto > 33) makes MeCN a good differentiating solvent, and extensive p K a data for bases in MeCN are available.…”