Consumer Science

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Browsing Consumer Science by Author "Hugo, C."

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    Degumming Gonometa postica cocoons using environmentally conscious methods
    (University of the Free State, 2015-02) Van der Merwe, Ismari; Steyn, H. J. H.; Hugo, C.
    English: The trend in the textile industry is at present towards eco-friendly processes and minimising the adverse ecological effects of production. Silk degumming is a high resource-consuming process, as far as water and energy are concerned. It further is ecologically questionable, because of the high environmental impact of effluents. The development of an effective degumming process would mean saving water and energy, recovery of valuable by-products such as sericin peptides, and lower environmental impact of effluents. The aim of this study was to develop and evaluate environmentally conscious degumming methods that could discriminate between sericin and fibroin, without harming the fibroin. The methods used and evaluated as environmentally conscious methods were tested against Orvus paste and all the samples were exposed to the method at a constant temperature of 32°C and a period of 10 days. Results indicated that an increased degumming time resulted in a decrease in the silk fibroin average molecular weight. A clear band at 25 kDa appeared with all the methods, indicating that the light chains were separated from the heavy chains during degumming. The degumming weight loss ranged from 27 to 41% over a time period of 10 days. Two of the methods namely the combination Orvus paste and Eucalyptus oil and catholyte were more efficient than Orvus paste. The SEM micrographs showed no fibrillations. This indicated further that the degumming methods were successful; the sericin was removed without damage done to the surfaces of the fibres. The maximum load and displacement means of the fibres differed with the different degumming methods applied. The strongest fibres were obtained from the control method. The weakest fibres came from the Vermicompost method. The results demonstrated that the environmentally conscious methods allow efficient, low cost degumming of sericin.
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    Evaluation of the antimicrobial effect and strength properties of polyester, polyester/cotton and cotton treated with Anolyte
    (University of the Free State, 2011) Vermaas, Jana F.; Steyn, H. J. H.; Hugo, C.
    English: Textile materials are usually treated with chemicals like sodium hypochlorite and high temperatures to ensure sterility. This poses two potential problems: (1) it has a negative effect on strength properties of the textile fabric; (2) the harmful chemicals are discarded into the environment. Therefore, better and safer methods need to be investigated. A process has been developed where electro-chemically activated water (Anolyte) is produced by an anode-cathode system and the process is described as a change of the molecular state of the water. After production, the Anolyte exists in a metastable state while containing many free radicals and a variety of molecules and a very high oxidation-reduction potential. It returns to a stable state after 48 hours and become inactive again and, therefore, it is not a threat to the environment when discarded after use. Anolyte has been shown to be an effective disinfection agent in other areas such as the food industry. The aim of this study was to determine if Anolyte could reduce E. coli and Staph. aureus on textiles to the same extent as sodium hypochlorite and be effective without implementing such high temperatures. The influence of the Anolyte on textile material should also be evaluated to ensure that it could be used without damaging textile materials more than the currently used disinfection agents. The antimicrobial effect of the Anolyte was determined by contaminating cotton, polyester and polyester/cotton fabric swatches with E. coli and Staph. aureus, respectively. Survival was determined after laundering with the respective wash liquors. AATCC Test Method 61- 2009 was used with the LaunderOmeter. Wash liquors included filtered water, phosphate reference detergent B, sodium hypochlorite and Anolyte. Temperatures were maintained at 24, 30 or 60°C. The cotton, polyester/cotton and polyester were laundered for 5, 10 or 20 cycles respectively for the evaluation of the influence on tensile strength and tearing strength. The tensile strength tests were conducted with the Instron Tensile Tester and ISO/SANS 13934-1:1999 test method. The tearing strength tests were conducted with the Elmendorf Tearing Strength tester as per ASTM Test Method D 1424 - 63. The results indicated that Anolyte destroyed all E. coli and Staph. aureus on all the fabrics regardless of the temperature. The effect of the other agents were enhanced by the increasing temperature, but after laundering at 60°C no survival was found as a result of the high temperature. The Anolyte did not influence the strength properties of the cotton, polyester and polyester/cotton fabrics to a larger extent than the detergent or sodium hypochlorite solution. An increase in maximum load required to break the fabric and displacement at maximum load was found for the cotton and polyester/cotton fabrics after laundering treatments, while a decrease was caused after laundering of the polyester fabric. A decrease in tearing strength of all the fabrics was found after laundering with the treatments. The Anolyte also did not affect the dimensional stability of the fabrics. It could be concluded that the Anolyte is a viable alternative to currently used sodium hypochlorite, while it is effective at low temperatures. The Anolyte do not affect the textile fabrics more negatively than the detergent and sodium hypochlorite combination, and could, therefore, be a successful alternative.