Development of anti-felting wool fabric
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Date
2021-06
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Publisher
CCSHAU, Hisar
Abstract
Wool fabric is known for its luxury and unique properties like breathability, excellent thermal insulation, flame retardancy, thermo-regulation and comfort properties. However, poor dimensional stability is one of the major limitations of wool fabrics that is caused by the progressive fibre entanglement in the wool fabric after repeated launderings. Thus, there is an imperative need to develop a treatment which not only prevent the wool from felting but also take care of the nature and textile material itself. Therefore, the present study was undertaken to impart the anti-felting treatment to wool fabric using eco-friendly biopolymers and enzymes. Three biopolymers and four enzymes were selected for imparting anti-felting treatment to wool fabric. The pad-dry-cure method for biopolymer treatment and exhaust method for enzyme treatment of wool fabric were selected on the basis of maximum shrink resistance obtained after washing that included one relaxation cycle and three felting cycles. For standardization of anti-felting biopolymer treatment, different variables i.e. padding bath components (biopolymer, cross-linking agent, catalyst), pH, material to liquor ratio, treatment temperature and time, drying temperature and time, curing temperature and time were optimized on the basis of least percent area shrinkage achieved by treated wool fabric. For standardization of anti-felting enzyme treatment, concentration and material to liquor ratio for each selected enzyme were optimized on the basis of obtained minimum area shrinkage to wool fabric after washing. As enzymes are very sensitive to pH, treatment temperature and time, thus these treatment variables were kept specific as provided by the manufacturers. Anti-felting biopolymer and enzyme treatments were imparted to wool fabric using their optimized concentrations and conditions. Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis of biopolymer and enzyme treated wool fabrics was done. The physical (preliminary, mechanical and performance) and functional properties (antibacterial and ultraviolet protection) of treated wool fabrics were tested to analyze the effect of anti-felting treatments. The durability of anti-felting biopolymer and enzyme treatments was assessed after washing, ironing and perspiration. The effect of anti-felting treatments on dyeability of the wool fabric with natural and synthetic dyes was also analyzed.
Anti-felting biopolymer treatment was given to wool fabric through pad-dry-cure method with all the three selected biopolymers using optimized concentrations of padding bath components i.e. 0.5 percent for chitosan, gum arabic and wheat starch biopolymers, 6 percent for citric acid cross-linking agent and 6 percent for sodium dihydrogen orthophosphate catalyst maintaining material to liquor-ratio 1:30 having neutral pH at 35°C temperature for 10 minutes. The 60°C drying temperature with 30 minutes and 145°C curing temperature with 10 minutes were optimized on the basis of obtained maximum shrink resistance to wool fabric. Anti-felting enzyme treatment was imparted through exhaust method to wool fabric with optimum concentration of 2 percent for laccase and transglutaminase and 1 percent for lipase and protease enzymes keeping optimum MLR of 1:30. The enzyme treatment of wool were carried out using enzyme specific conditions i.e. 4.5 pH for lacccse, 8.5 pH for lipase and protease and 7.0 pH for transglutaminase enzyme maintaining 55ºC temperature for 60 minutes. FE-SEM analysis exhibited blunt scales after each biopolymer treatment and reduced sharpness of scales with all the four enzyme treatments. FTIR analysis exhibited presence of various functional groups at different peaks in biopolymer and enzyme treated wool fabrics. Preliminary properties i.e. fabric count, weight and thickness of wool fabric exhibited an increase when treated with biopolymers and enzymes. The bending and tensile properties of biopolymer and enzyme treated wool fabrics found comparable with that of scoured fabric while the frictional properties of wool fabric were found to be increased significantly after biopolymer and enzyme treatments. The moisture content and regain of all the treated wool fabrics found comparable with standard moisture content (13.50 %) and regain (16.00 %) of wool fabric. The wettability of scoured wool fabric remain unchanged after anti-felting biopolymer and enzyme treatments. The crease recovery angle of scoured wool fabric increased after biopolymer and enzyme treatments. The air permeability was found to be increased after treatment with chitosan and gum arabic biopolymers and lipase and transglutaminase enzymes. The whiteness of wheat starch and all the enzyme treated wool fabrics found comparable with scoured wool fabric. The whiteness index of all the treated fabrics was much lower than fabric treated with conventional method of shrink resistance. It was observed that all the treated wool fabrics exhibited good antibacterial activity against S. aureus and E. coli bacteria. The UPF value of scoured wool fabric enhanced after biopolymer and enzyme anti-felting treatments that came under excellent protection category. Both the anti-felting treatments were found to be effective to give dimensional stability to wool fabric against washing, ironing and perspiration. Biopolymer treated wool fabric dyed with natural dye showed increased colour strength. Thus, biopolymer and enzyme treatments can be used as viable and sustainable alternatives to conventional treatments for developing machine washable shrink-resistant wool fabric without any adverse effect on fabric properties.