Sökning: "Brightness reversion"

Hittade 5 avhandlingar innehållade orden Brightness reversion.

1. 1. 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

3. 2. The link between kraft cooking and bleaching : influence on ECF bleachabiblity and bleaching effluent parameters

   Författare :Magnus Björklund; []
   Nyckelord :;

   Sammanfattning : The link between kraft cooking and bleaching was investigated, with the focus on how cooking kappa number, cooking conditions and pre-bleaching stages influence ECF bleachability and environmental parameters in the bleaching effluent. In one part of the study standard cooking conditions were used to produce birch and spruce pulps of different kappa numbers and then we studied how the AOX in the ECF bleaching effluent was affected by oxygen delignification, and hot acid stages. LÄS MER

4. 3. Xylan Reactions in Kraft Cooking : Process and Product Considerations

   Författare :Sverker Danielsson; Mikael Lindström; Richard Gustafson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Xylan; Kraft cooking; Paper strength; Sheet density; Methylglucuronic acid; Hexenuronic acid; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Sammanfattning : Xylan is the main hemicellulose in birch, eucalyptus, and most other hardwood species. During kraft pulping a series of chemical reactions and physical processes involving xylan takes place. LÄS MER

5. 4. Xylan reactions in kraft cooking and their influence on paper sheet properties

   Författare :Sverker Danielsson; Mikael E. Lindström; Stefan Backa; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Sammanfattning : Xylan is the main hemicellulose in birch, eucalyptus, and most other hardwood species. During kraft pulping a series of chemical reactions and physical processes involving xylan take place. LÄS MER

7. 5. 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