Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The effect of charged groups on the beatability of pulp fibres
KTH, School of Chemical Science and Engineering (CHE).
2011 (English)Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesisAlternative title
Laddade gruppers inverkan på malbarheten hos massafibrer (Swedish)
Abstract [en]

The purpose of this bachelor thesis was to investigate how charged groups within the pulp fibre affect the beatability and the strength of the papers. To obtain different levels of charges on the pulp it was carboxymethylated. The different pulp samples were beaten to different degrees to investigate how charges interact with the beating. A PFI-mill was used for the beating because of the relatively homogenous effect on the fibres and the low demand for pulp fibres for each beating. The influence of the amount of charged groups on the surface and bulk swelling, as a result of the beating process, was evaluated.

 

The fibres were then analysed in a Fibre tester and using a microscope to see what had happened to the fibre structure.  The results showed that the PFI-mill mainly affects the surface of the fibres. The beatability, defined as the swelling obtain for a specific energy input, was greatly increased by the introduction of charges. It was also shown that there is a possibility to replace some of the energy input in the mill with the introduction of charges to obtain the same swelling and strength.

 

Paper sheets were formed from the different samples and some mechanical properties were analyzed. It was shown that the strength was initially improved by the introduction of charges but the improvement was partially lost during the beating. At the highest rate of beating the difference in strength between the samples had disappeared. This can be explained by the fact that the fibres, from the sample with highest number of charges, were destroyed. Microscopic images showed that the fibre was delaminated and at some sites there were extreme balloon-like swellings

Abstract [sv]

Syftet med detta examensarbete var att undersöka hur laddade grupper hos massafibrer påverkar malbarheten och styrkan hos de papper som tillverkats av dessa fibrer. För att skapa olika laddningsnivåer karboxymetylerades viss del av massan för att introducera laddade grupper, två delar av ursprungsmassan karboxymetylerades och en del användes som referensmassa.

 De olika massaproverna maldes i olika nivåer för att undersöka hur laddningarna och malningen interagerade. En PFI-kvarn användes för att mala fibrerna då det endast krävs små mängder fibrer och denna typ av kvarn påverkar fibrerna relativt homogent.

Fibrerna analyserades sedan i en Fibre tester och med ett mikroskop för att se vad som hade hänt med fiberstrukturen. Resultaten visade att en PFI-kvarn till största delen påverkar fibrernas yta.  Malbarheten, som definierades som den svällning som åstadkoms vid en viss energiinsats i form av malvarv i kvarnen, ökades markant då ytterligare laddningar fanns närvarande i fibrerna. Det visades också att det går att ersätta en del av malningen med introduktion av laddningar till fibrerna för att uppnå samma svällning och styrka.

Pappersark tillverkades därefter av de olika massatyperna och några mekaniska egenskaper testades. Det visades att styrkan ökades initialt av introduktionen av laddningar men denna förbättring minskade vid malningen. Vid den högsta malgraden hade skillnaden mellan de olika massorna försvunnit. Det kan förklaras av att fibrerna, från den massatyp med mest laddningar, hade förstörts. På vissa ställen hade fibern helt delaminerats och extrema ballonglika svällningar fanns.

Place, publisher, year, edition, pages
2011. , 30 p.
Keyword [en]
Kraft pulp, softwood, carboxymethylation, swelling, PFI beating, refining, beatability, charged groups
National Category
Chemical Engineering
Identifiers
URN: urn:nbn:se:kth:diva-35226OAI: oai:DiVA.org:kth-35226DiVA: diva2:425918
Subject / course
Chemical Engineering
Educational program
Bachelor of Science in Engineering - Chemical Engineering
Uppsok
Physics, Chemistry, Mathematics
Supervisors
Examiners
Available from: 2011-11-28 Created: 2011-06-22 Last updated: 2015-06-26Bibliographically approved

Open Access in DiVA

fulltext(946 kB)868 downloads
File information
File name FULLTEXT01.pdfFile size 946 kBChecksum SHA-512
598c485cbfe414f03003fc8b2bd8ac1e650c6d2392086b90031a4bbdef5f6e93feb5110d9e709388f1adcc2de10a75c4bb752c4a9d5ffd803ed3d5df934a87ca
Type fulltextMimetype application/pdf

By organisation
School of Chemical Science and Engineering (CHE)
Chemical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 868 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 167 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf