Dyeing of polypropylene with some azo disperse dyes of basic character via chlorinatieon route

摘要

Polypropylene fabric, after chlorination by sodium hypochlorite under an optimized condition, was dyed separately with twelve azo disperse dyes of basic character in both alkaline and acidic medium. The higher affinity of these dyes to chlorinated polypropylene than to unmodified polypropylene has been observed in both acidic and alkaline medium with a few exceptions. The possible mechanism of higher affinity of such dyes to chlorinated polypropylene is shown and explained. The influence of dye structure and substituent groups on dye uptake and fastness properties is discussed on the basis of inductive effect, electrostatic interactions, steric cause, etc. It is observed that these dyes with electron donating groups as substituents when applied in acid medium give higher dye uptake and improved fastness properties with a few exceptions for other structural interactions including steric cause.