1. Chemical decomposition of thermosetsVasil Handjiski, 2024, undergraduate thesis Abstract: This bachelor thesis depicts the chemical degradation of polyurethane and melamine formaldehyde, which are representatives of thermosets. A high–pressure reactor was used to perform chemical degradation. The effectiveness of the chemical degradation of the selected thermosets was monitored by measuring pH, total organic carbon (TOC) and total nitrogen (TN) of the liquid residues. The remaining solid material was characterized by infrared spectroscopy and the mass loss was determined. Using these analytical methods, it was concluded that the chemical degradation depends on the temperature and the duration of the reactions as well as the reaction medium. It was found that “white liquor” is a more effective medium for the chemical degradation of polyurethane and melamine formaldehyde than water.
Keywords: chemical degradation, polyurethane, melamine formaldehyde, FTIR
Published in DKUM: 22.10.2024; Views: 0; Downloads: 0 |
2. Grafting of cotton with [beta]-cyclodextrin via poly(carboxylic acid)Bojana Vončina, Alenka Majcen Le Marechal, 2005, original scientific article Abstract: Cyclodextrins are cyclic oligosaccharides. Cyclodextrin molecules can form inclusion complexes with a large number of organic molecules. The properties of cyclodextrins enable them to be used in a variety of different textile applications. Cyclodextrins can act as auxiliaries in washing and dyeing processes, and they can also be fixed onto different fiber surfaces. Because of the complexing abilities of cyclodextrins, textiles with new functional properties can be prepared. Poly(carboxylic acid)s such as 1,2,3,4-butane tetracarboxylic acid (BTCA) are well-known non-formaldehyde crosslinking reagents. BTCA has four carboxylic acid groups, which can react with hydroxyl groups of cellulose and form stable ester bonds. We crosslinked -cyclodextrin molecules on hydroxyl groups of cellulose via BTCA.
Keywords: textile fibres, chemical modification, beta cyclodextrines, butane tetracarboxylic acid, BTCA, FTIR, host-guest systems, formaldehyde-free crosslinking reagents
Published in DKUM: 01.06.2012; Views: 2215; Downloads: 74
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3. Evaluation of analytical methods for the determination of free formaldehyde on textile substrateBojana Vončina, Alenka Majcen Le Marechal, Darinka Brodnjak-Vončina, 2007, original scientific article Abstract: Release of formaldehyde from durable press-treated fabrics is a problem for human health and safety because formaldehyde is suspected to be carcinogenic. The accuracy of the standard test method for the free formaldehyde determination, Japan Law 112, depends on the formaldehyde content of the sample. The detection of low formaldehyde contents is particularly important in fields, like children clothing, so the application of high-performance liquid chromatography was evaluated. The results obtained by the standard testmethod, Japan Law 112, where UV/Vis spectrometer was used, were compared with the results obtained by HPLC method in which separation was performed on an RP C18 column with water-methanol as a mobile phase. It was shown that the detection limit and limit of quantification were improved using the HPLC method.
Keywords: analizna kemija, formaldehid, določevanje formaldehida, celulozna vlakna, HPLC, UV/VIS, analytical chemistry, formaldehyde, determination of formaldehyde, cellulose fibres, HPLC, UV/VIS
Published in DKUM: 31.05.2012; Views: 2925; Downloads: 123
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