Abstract
The enzymatic hydrolysis of polyamide fibres yields amino and carboxylic groups. These groups can be found in solution treatments as polyamide monomers and soluble oligomers. The amino groups can also be found at the surface of the fibres as end group chains. In this paper we report two methods to quantify the formation of these groups as a result of the enzymatic action. Soluble amino groups can be quantified with 2,4,6-trinitrobenzenesulfonic acid (TNBS), which yields a coloured complex which can be determined spectrophotometrically. The amino groups on the fibre surface can be quantified by reaction with a wool reactive dye and determination of colour intensities after a dyeing procedure below the glass transition temperature of polyamide.