Sökning: "photoyellowing"

Hittade 3 avhandlingar innehållade ordet photoyellowing.

1. 1. Modification of lignin-rich paper for improvement of mechanical and optical properties

   Författare :Magnus Paulsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TMP; acetylation; photoyellowing; sodium borohyride; CTMP; stabilization; phenol groups; paper properties;

   Sammanfattning : .... LÄS MER

3. 2. 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

4. 3. 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