Dyeing of Polymeric Materials

The spatial distribution of the dye within the polymer provides information required to model the dyeing process. Confocal Raman microscopy (using an oil immersion objective) has emerged as a powerful technique to obtain accurate profiles of the dye distribution as a function of depth [148]. The technique is specifically suited to this apphcation because of the high Raman activity of azo-dyes used in the dyeing process and thus enables the dye to be detected at low concentrations. Depth profiling of polymers dyed from a supercritical solution have also been achieved with the use of photoacoustic (PA) spectroscopy [149]. 

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The same properties that make SCCO2 attractive for extraction purposes can be exploited in the impregnation and dyeing of polymeric materials [105]. By applying supercritical conditions, it is possible to impregnate polymers with pharmaceuticals, flavors, and fragrances, or with additives such as pigments, stabilizers, and... 

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