Sökning: "dissolving pulps"

Visar resultat 1 - 5 av 17 avhandlingar innehållade orden dissolving pulps.

  1. 1. Dissolving pulp : Multivariate Characterisation and Analysis of Reactivity and Spectroscopic Properties

    Författare :Kristina Elg Christoffersson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Dissolving pulp; reactivity; solid state 13C NMR spectroscopy; NIR spectroscopy; multivariate analysis; cellulose; viscose; Kemi; Chemistry; Kemi;

    Sammanfattning : Various chemical properties can be used to characterise dissolving pulp. The quality of the pulp must be carefully controlled to ensure that it meets the requirements for its intended use and the further processes to be applied. LÄS MER

  3. 2. Activation of dissolving pulps prior to viscose preparation

    Författare :Niklas Kvarnlöf; Ulf Germgård; Leif J. Jönsson; Carl-Axel Söderlund; Herbert Sixta; Karlstads universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dissolving pulp; enzyme; reactivity; viscose; Chemical engineering; Kemiteknik; Chemical Engineering; Kemiteknik;

    Sammanfattning : The conventional viscose manufacturing process is a mature process that needs to be improved with respect to its environmental impact and its production cost structure. Therefore a research study has been done with the aim to improve the reactivity of the dissolving pulp used, in order to reduce the chemical demand in the viscose process and thus reduce the cost and indirectly the environmental impact. LÄS MER

  4. 3. On the importance of oxidizable structures in bleached kraft pulps

    Författare :Olena Sevastyanova; Göran Gellerstedt; Colodette Jorge; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bleached pulps; betula; eucalyptus; 5-formyl-2furancarboxylic acid; 2-furancarboxylic acid; hexenuronic acid; kappa number; kraft pulps; oxidation equivalents; Cellulose and paper engineering; Cellulosa- och pappersteknik;

    Sammanfattning : After cooking, kraft pulps always contain not only residual lignin but also significant amounts of hexenuronic acid and other non-lignin structures oxidizable by permanganate under the standard kappa number determination conditions. These here referred to as false lignin. LÄS MER

  5. 4. Improvement on cellulose accessibility and reactivity of different wood pulps

    Författare :Viviana Köpcke; Monica Ek; KTH; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; cellulose; accessibility; reactivity; enzymatic treatment; mechanical treatment; chemical treatment; dissolving pulp; paper grade pulps; Wood fibre and forest products; Träfiber- och virkeslära;

    Sammanfattning : Cellulosans tillgänglighet och reaktivitet är nyckelparametrar vid framställning av regenererad cellulosa och cellulosaderivat. Det är välkänt att på grund av cellulosans kristallina struktur är tillgängligheten begränsad för lösningsmedel och olika reagens. LÄS MER

  7. 5. Conversion of Wood and Non-wood Paper-grade Pulps to Dissolving-grade Pulps

    Författare :Viviana Köpcke; Monica Ek; Herbert Sixta; KTH; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; Wood fibre and forest products; Träfiber- och virkeslära;

    Sammanfattning : Dissolving-grade pulps are commonly used for the production of cellulose derivatives and regenerated cellulose. To obtain products of high quality, these so-called "special" pulps must fulfill certain requirements, such as high cellulose content, low hemicellulose content, a uniform molecular weight distribution and high cellulose reactivity. LÄS MER