Browsing by Author "Davulcu, Asim"

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    Enzymatic one - bath desizing - bleaching - dyeing process for cotton fabrics
    (Sage Publications, 2009-08) Davulcu, Asim; Eren, Hüseyin Aksel; Anis, Pervin; Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; AAH-3948-2021; 7003950739; 6505864579
    The objective of this study was to develop a new process to desize, bleach, and dye starch-sized cotton fabrics in one bath using enzymes. Desizing was performed with an amyloglucosidase/pullanase enzyme (Dextrozyme DX, manufactured by Novozymes) instead of a conventional amylase enzyme in order to hydrolyze starch into single glucose units. Multifect GO 5000L (Genencor) glucose oxidase enzyme was used to yield hydrogen peroxide from the glucose generated during desizing; bleaching was performed by this enzymatically generated hydrogen peroxide. Decomposition of hydrogen peroxide after bleaching was done with Terminox Ultra 10L (Novozymes) catalase enzyme. The fabric was dyed in the same bath with the selected monochlortriazine reactive dyes (DyStar). The amount of glucose generated during desizing was 4000 135 mg/l and it yielded 765 +/- 15 mg/l hydrogen peroxide during glucose oxidase enzyme treatment. The whiteness index of the enzymatically bleached fabric was 71.0 +/- 1.2 stensby degree. The color yields of the enzymatically treated samples were comparable to the conventionally treated samples. All enzymes used in this study were commercial grades having the advantages of easy storage and supply compared to the pure enzymes used in earlier studies. The advantages of the new one-bath process were: less auxiliary demand; lower environmental impact; and energy and water savings compared to the conventional desizing, scouring, bleaching, and dyeing sequence.
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    Enzymatic pre-treatment of cotton. Part 2: Peroxide generation in desizing liquor and bleaching
    (Inst Chemical Fibres, 2009) Davulcu, Asim; Aniş, Pervin; Eren, Hüseyin Aksel; Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; AAH-3948-2021; 6505864579; 7003950739
    The objective of this study was to utilise desizing liquors of starch-sized fabrics using glucoseoxidase enzymes for bleach to produce hydrogen peroxide front glucose units of the starch removed; glucoseoxidase enzymes are efficient only at high glucose doses. In the first part of this paper, glucose generation in a desizing bath was discussed and an optimum recipe was obtained with an amyloglucodidase/pullanase mixture enzyme. In this study, process optimisation for the glucose oxidase enzyme was undertaken in order to generate hydrogen peroxide in the desizing liquor and then bleaching with the peroxide generated. Results indicated that sufficient hydrogen peroxide, about 800 mg l(-1), could be generated to perform successful enzymatic bleaching; however, the bleaching was compatible with the conventional peroxide type only in the alkali pH range. The maximum whiteness obtained by enzymatic treatment was 73.8 Stensby degree, whereas the whiteness of the conventionally treated fabric was 79.4 Stensby degree.