Evaluation of bio-finishing

The removal of cellulosic fibres to improve pilling performance, soften hand, and create an abraded appearance requires not only enzymatic hydrolysis but also mechanical action to carry away reaction by-products physically. The final results from the hydrolysis with respect to appearance and hand are affected just as much by the mechanical components of the process as by the chemical components. Therefore, laboratory evaluations of bio-finished goods can only produce relative rather than absolute results. 

Enzyme suppliers determine the activity of their products by measuring the extent of the catalysed reaction under carefully controlled conditions. A standard test exists for amylases (AATCC Test Method 103) , but the evaluation of cellulases is more complex and can vary from supplier to supplier. One common method is to measure the degradation of carboxymethylcellulose solutions. Another is to determine the weight or strength loss of standard cotton fabrics under laboratory conditions where there is a correlation problem, because the mechanical conditions of the technical application are different to the laboratory ones. For example, the hydrolysis degree, HD, is determined by HD = (m - m)/m where and m are the weight of the test material before and after bio-fmishing. 

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