Browsing by Author "Cavaco-Paulo A."

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    Cotton fabric: A natural matrix suitable for controlled release systems
    (2007-06-01) Todorova S.; Silva C.; Simeonov N.; Cavaco-Paulo A.
    The possibility to use cotton as a matrix for controlled release systems was studied by covalently attaching a model compound, specifically the reactive dye Remazol Brilliant Blue R to its surface. Afterwards the fabric was coated with a commercial cellulase. The release of the dye, obtained by the hydrolysis of cotton fibres in sweat buffer, was monitored. The reducing sugars concentration increased for both fabrics (with and without the dye covalently fixed) while the increase in the absorbance was only attained for the dyed cotton, as expected. These results confirm the viability of using cotton as a natural matrix for controlled released systems while presenting a promising approach to immobilize covalently other substances in cotton garments, like fragrances, which could be released by the action of human sweat. © 2007 Elsevier Inc. All rights reserved.
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    Lipases to improve the performance of formaldehyde-free durable press finished cotton fabrics
    (2002-07-28) Tzanov T.; Stamenova M.; Betcheva R.; Cavaco-Paulo A.
    Lipases were used to restore partially the strength losses of cotton fabrics crosslinked with 1,2,3,4-butanetetracarboxylic acid. The enzymatic hydrolysis of the ester linkages at low temperature and neutral pH resulted in 10% strength recovery, coupled with a slight deterioration of the crease-resistance effect. The conventional alkaline hydrolysis provided higher strength recovery, however provoked considerable change in the durable press performance of the fabrics.
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    Phosphorylation of cotton cellulose with baker's yeast hexokinase
    (2002-11-25) Tzanov T.; Stamenova M.; Cavaco-Paulo A.
    Here we report for the first time on phosphorylation of cotton cellulose using baker's yeast hexokinase and phosphoryl donor adenosine-5′-triphosphate. An enzy matic assay was adopted for determination of the degree of phosphorylation of cellulose. This functional modification of cellulose resulted in improved colorability and flame resistance.
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    Proteases to improve the mechanical characteristics of durable press finished cotton fabrics
    (2003-01-31) Stamenova M.; Tzanov T.; Betcheva R.; Cavaco-Paulo A.
    N-Methylol reagents are conventional crosslinking agents that are still widely used in textile industry to produce crease-resistant cotton fabrics. In this work serine proteases were used to recover the strength of fabrics, crosslinked with N-hydroxymethylacrylamide. Nearly one half of the strength loss of crosslinked cotton fabrics could be restored after protease treatment, while the wrinkle recovery angle (WRA) decreased only slightly. The enzymatic hydrolysis of the amide cross-links in the durable pressed cellulose was confirmed by FT-IR analysis and dyeability with an acid dye.