NOPR Collection:

Optimum conditions for surface modification of PET by lipase enzymes produced by Egyptian bacilli in comparison with standard one

2016-07-20T05:01:32Z

Title: Optimum conditions for surface modification of PET by lipase enzymes produced by Egyptian bacilli in comparison with standard one Authors: El-Ola, Samiha M Abo; Moharam, Maysa E; El-Bendary, Magda A Abstract: The optimum conditions for surface modification of polyethylene terephthalate (PET) by lipase enzymes produced under economic conditions by two Egyptian bacilli (Bacillus isolate 6C and Bacillus isolate 5W) have been obtained and then compared with reference sample. The optimum conditions are found to be 0.04 mg/mL enzyme concentration, 0.5 h incubation time, room temperature (25 ºC) and pH 8 under shaking conditions. Addition of 0.15% CaCl₂ to the treatment bath enhances both the hydrophilicity (18-26%) and dyeability (22- 194%). The effect of hydrolytic activity of enzymatic process on the weight loss after treatment does not show any significant difference. Printing both untreated and treated PET fabrics with transfer printing shows high leveling properties w.r.t. ∆E values, where it is considered as acceptable values of color differences. PET treated with different sources of lipase enzyme under optimum conditions shows good physical properties and high water regain. SEM of the surface of lipase treated PET samples shows cracks and voids compared to smooth surface of untreated PET fabrics. Page(s): 165-172

Improving light fastness of reactive dyed cotton fabric with antioxidant and UV absorbers

2016-07-20T05:00:50Z

Title: Improving light fastness of reactive dyed cotton fabric with antioxidant and UV absorbers Authors: Thiagarajan, P; Nalankilli, G Abstract: Cotton fabrics have been dyed with C. I. Reactive Yellow 84, C. I. Reactive Red 22 and C. I. Reactive Blue 19 dyes and the effect of some commonly used antioxidants and UV absorbers is studied in order to improve light fastness property. The antioxidants such as gallic acid, vitamin C and cafeic acid, and the UV absorbers such as 2-hydroxybenzophenone and phenyl salicylate have been applied on reactive dyed cotton fabric by exhaust method. Treated samples are then tested for fastness properties as per international standards. The results show no change in colour depth during after treatment. In all the cases, the use of UV absorbers or antioxidants improves the light fastness of dyed fabrics. The most effective light fastness improvement is found by the application of vitamin C. Page(s): 161-164

Development of UV protective electrospun layers for high performance fibres for high altitude applications

2016-07-20T04:47:36Z

Title: Development of UV protective electrospun layers for high performance fibres for high altitude applications Authors: Seyam, Abdel-Fattah M; Won, Jessica Abstract: In this study, a range of lightweight UV protective layers has been developed from electrospun polyurethane loaded with different amount of rutile TiO₂ nanoparticles using electrospinning with variable speed drum (collecting surface). To assess the degree of protection of the manufactured layers, a braid from Zylon fibres has been sheathed with the protective layers of different weight per braid unit length and the strength of yarns raveled from the braids is measured. The strength retention after exposure to artificial UV rays in Atlas Weatherometer for six days is used as a measure of the degree of sheath protection. Electrospun polyurethane layers loaded with 1% of TiO₂ with weight of 2.29 g/m braid, processed at high speed collector (87.7 m/min), provide the highest protection among the developed electrospun polyurethane layers. Page(s): 121-125

Biopolishing of cotton fabric with fungal cellulase and its effect on the morphology of cotton fibres

2016-07-20T05:00:03Z

Title: Biopolishing of cotton fabric with fungal cellulase and its effect on the morphology of cotton fibres Authors: Saravanan, D; Lakshmi, S N Sree; Raja, K Senthil; Vasanthi, N S Abstract: Attempt has been made to analyse structural changes in cotton fibres occurred during biopolishing using cellulases obtained from Trichoderma reesei. Cellulase hydrolysis results in weight loss of the samples, which, in turn, results in the splitting of fibres and removal of surface irregularities of the fibres as revealed by SEM images. Degree of crystallinity is not influenced by the biopolishing process due to random hydrolysis of the cellulase enzymes on cotton fibres. Lateral order of the crystallites, measured between (101) and (10) peaks of the x-ray diffraction reduces from 0.662 to 0.667 on account of the hydrolysis though the crystallite thickness measured perpendicular to (002) plane remains unchanged. FTIR results reveal the increased -OH bending, CH₂ in-plane bending, and C-H vibrations of the cellulose chains in the biopolished cotton samples using cellulase. Page(s): 156-160