Sökning: "yellowing"

Visar resultat 1 - 5 av 14 avhandlingar innehållade ordet yellowing.

  1. 1. Light-Induced Yellowing of High-Yield Pulps. The Effect of Acetylation

    Författare :Magnus Paulsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; yellowing; mechanical properties; hydroxyl groups; phenolic groups; paper; high-yield pulps; chromophores; model compounds; acetylation; inhibition;

    Sammanfattning : This thesis is a contribution to the understanding of the mechanism of photoyellowing of high-yield pulps. It also gives some general information about the reactivity of different functional groups in lignin towards acetic anhydride. LÄS MER

  3. 2. 13C-Enriched Dehydrogenation Polymers Used for Studying Light-Induced Yellowing of Lignocellulosic Materials

    Författare :Jim Parkås; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lignin model compounds; differentiating xylem; yellowing; Picea abies; 13C NMR spectroscopy; lignin; DHP; 13C-enrichment; solid state; spruce;

    Sammanfattning : This study deals with the use of selectively 13C-enriched dehydrogenation polymers (DHPs) as models of lignin in lignocellulosic materials for elucidating the reaction pathways involved in light-induced yellowing. Methods for the synthesis of coniferin, a precursor to lignin and DHP, selectively 13C-enriched in the aromatic ring (positions 1, 3, 4, and 5) have been developed. LÄS MER

  4. 3. Light-induced yellowing studied with ¹³C-enriched CW-DHP and solid state ¹³C NMR spectroscopy

    Författare :Jim Parkås; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; solid state; yellowing; picea abies; differentiation xylem; spruce; DHP; lignin; 13C NMR spectroscopy; 13C-enrichment;

    Sammanfattning : .... LÄS MER

  5. 4. on the thermal yellowing of TCF- bleached birch kraft pulp

    Författare :Anders Granström; KTH; []
    Nyckelord :Ageing; Brightness reversion; Chalaton; Colour reversion; Dicarboxylic acids; Discoloration; HexA; Hexenuronic acid; Kraft pulp; Metal profile; Thermal yellowing; Xylan;

    Sammanfattning : .... LÄS MER

  7. 5. Coconut lethal yellowing phytoplasma disease in Mozambique : diversity, host range, and the impact of farming practices on disease incidence

    Författare :Joao Bila; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

    Sammanfattning : The coconut palm (Cocos nucifera) is a major cash crop that is widely grown in coastal tropical regions of the world, including Mozambique. Outbreaks of coconut lethal yellowing disease (CLYD) are threatening the industry and the livelihood of a large part of the Mozambican population. LÄS MER