Sökning: "Alkali cellulose"

Visar resultat 1 - 5 av 34 avhandlingar innehållade orden Alkali cellulose.

  1. 1. Mercerization and Enzymatic Pretreatment of Cellulose in Dissolving Pulps

    Författare :Heléne Almlöf Ambjörnsson; Ulf Germgård; Thomas Nilsson; Storker Moe; Karlstads universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; alkali; carboxymethyl cellulose; cellulose I; cellulose II; cellulose dissolution; degree of substitution; enzymatic treatment; filterability; gel formation; mercerization; multivariate analytical methods; NIR FT Raman spectroscopy; sodium hydroxide; zink oxide; Chemical Engineering; Kemiteknik;

    Sammanfattning : This thesis deals with the preparation of chemically and/or enzymatically modified cellulose. This modification can be either irreversible or reversible. Irreversible modification is used to prepare cellulose derivatives as end products, whereas reversible modification is used to enhance solubility in the preparation of regenerated cellulose. LÄS MER

  3. 2. Experimental study of alkalinisation of cellulose in industrial relevant conditions

    Författare :Diana Carolina Reyes Forsberg; Ola Sundman; Bertil Eliasson; Ulf Germgård; Umeå universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Mercerisation; Alkalinisation; Cellulose I; Cellulose II; Alkali cellulose; Viscose; Cellulose ether; Carboxymethylcellulose; Sodium glycolate; Sodium diglycolate; Raman spectroscopy;

    Sammanfattning : Mercerisation of cellulose pulp with a solution of NaOH is the first step of manufacturing cellulose-based value-added products, e.g. viscose fibres and cellulose ethers. During this process, cellulose transforms into a swollen crystalline structure, alkali cellulose (Na-Cell). LÄS MER

  4. 3. Properties and performance of regenerated cellulose thermoset biocomposites

    Författare :Sunil Kumar Ramamoorthy; Jyrki Vuorinen; Högskolan i Borås; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; regenerated cellulose fibres; surface modification; alkali; silane; mechanical analysis; biocomposites; renewable resources; Resursåtervinning; Resource Recovery;

    Sammanfattning : Biocomposites have been developed to address the sustainability issues of nonrenewableresource based materials. These composites are often produced by reinforcing natural fibres in petroleum based thermoset resins or thermoplastic polymers. LÄS MER

  5. 4. Understanding overlooked molecular interactions in the cellulose/NaOH(aq) system

    Författare :Maria Gunnarsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; ATR-IR; dissolution; cellulose; NMR; urea; CO2; NaOH aq ;

    Sammanfattning : The cold NaOH(aq) system is a promising process for the production of textile fibres. Although the process has been studied for almost a century, there remain unsolved research issues, especially regarding the dissolution mechanism. LÄS MER

  7. 5. Biopolymers and materials from rapeseed straw biorefining

    Författare :Antonia Svärd; Ulrica Edlund; Elisabet Brännvall; Stefan Willför; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Rapeseed canola straw; biorefinery; hemicelluloses; lignin; cellulose; cellulose nanoparticles; films; grafting; thermoplastic; biocomposites; rapshalm; bioraffinaderi; hemicellulosa; lignin; cellulosa; cellulosa nano partiklar; hemicellulosafilm; ympning; termoplastisk; biokompositer; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : Rapeseed straw was fractionated through a hydrothermal process into its hemicellulose, lignin and cellulose components. In the first step, hemicellulose-rich fractions were extracted. Xylan-rich fractions with high molecular weight, 30,000 – 50,000 g/mol, were obtained at 110 °C and 1.5 M NaOH. LÄS MER