Enzymatic hydrolysis of nylon 6 fiber using lipolytic enzyme

This study confirms the structural changes of nylon 6 fibers using lipase by measuring the dyeability, hydrophilicity, chemical changes, and fastness properties. For this purpose, nylon 6 fabrics were first treated separately with different concentrations of lipase enzyme. The dyeing process was then carried out on the treated fabrics with two disperse and acid dyes. A UV‐vis spectrophotometer was used for determination of dyebath exhaustion. Acid and disperse dyes showed higher dyebath exhaustion on the enzyme treated samples compared to raw material. The intensity of major peaks in FTIR spectra of the lipase treated samples are in favor of chemical changes of the polypeptide functional groups in fabric. Tensile strength of treated fabrics was decreased due to enzyme treatment. The results of color measurements in the CIELAB system showed that the darkness of the samples increased with an increase in the enzyme percentage in the solution. The results of moisture regain showed that treatment of nylon fabrics with lipolytic enzymes caused to increase the moisture absorbency. The wash and light fastness properties of samples were measured according to ISO 105‐CO5 and Daylight ISO 105‐BO1 and discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of ammonia on madder‐dyed natural protein fiber

Of all the beautiful reds in nature, the only one vegetable source of good dyes ever discovered by man is madder. In this research natural protein fibers (i.e., wool yarns) were dyed with madder and then treated with different ammonia solutions. A UV–visible spectrophotometer was used to measure the absorbency of the remaining ammonia solution. The absorption curves showed the absorption transfer to the visible region. FTIR spectroscopy studies indicated that the changes in intensity at the peaks occurred when the madder‐dyed yarns were treated with ammonia solutions. The results of color measurement in the CIELAB system showed that the darkness of samples increased with an increase in the ammonia percentage in the solution. The vertical wicking test was also carried out on the madder‐dyed yarns and the ammonia‐treated samples. The results showed that the ammonia treatment causes a decrease in the wicking rate. A change of color was observed on the dyed samples when wash‐fastness tests were carried out. The results of light‐fastness tests showed more fading of the madder‐dyed yarns after ammonia treatment. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2704–2710, 2004