Measurements of dye absorption by cellulose triacetate using matching index of refraction absorption spectroscopy

Abstract

A simple method of analysis has been devised in which the uptake of disperse dyes in triacetate fabrics can be monitored using ordinary absorption spectroscopy. The experimental technique requires that a sample of triacetate fabric be immersed in a liquid having the same index of refraction as the constituent fibres, thus rendering the fabric transparent to visible light. Under these conditions, a dyed sample of fabric may be placed in the cell compartment of an ordinary ultraviolet/visible spectrometer allowing one to measure the absorption spectrum of the dye molecules located within the constituent triacetate fibres of the fabric sample. Values measured for the absorbance of several dyes incorporated within samples of triacetate fabric are shown to satisfy the Beer–Lambert law, thus enabling one to measure the rate of dye uptake by triacetate fabric samples placed in infinite dyebaths.