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
Preparation of dry ultra-porous cellulosic fibres: Characterization and possible initial uses
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.ORCID iD: 0000-0001-9176-7116
KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.ORCID iD: 0000-0001-8622-0386
2013 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 92, no 1, 775-783 p.Article in journal (Refereed) Published
Abstract [en]

Dry ultra-porous cellulose fibres were obtained using a liquid exchange procedure in which water was replaced in the following order: water, methanol, acetone, and finally pentane: thereafter, the fibres were dried with Ar(g). The dry samples (of TEMPO-oxidized dissolving pulp) had a specific surface area of 130 m(2) g(-1) as measured using BET nitrogen gas adsorption. The open structure in the dry state was also revealed using field emission scanning electron microscopy. This dry open structure was used as a scaffold for in situ polymerization. Both poly(methyl methacrylate) and poly(butylacrylate) were successfully used as matrix polymers for the composite material (fibre/polymer), comprising approximately 20 wt% fibres. Atomic force microscopy phase imaging indicated a nanoscale mixing of the matrix polymer and the cellulose fibril aggregates and this was also supported by mechanical testing of the prepared composite where the open fibre structure produced superior composites. The fibre/polymer composite had a significantly reduced water absorption capacity also indicating an efficient filling of the fibre structure with the matrix polymer.

Place, publisher, year, edition, pages
2013. Vol. 92, no 1, 775-783 p.
Keyword [en]
Cellulose fibre, Composite, In situ polymerization, Liquid exchange, Open structure, Surface area
National Category
Polymer Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-103402DOI: 10.1016/j.carbpol.2012.09.090ISI: 000313146900110Scopus ID: 2-s2.0-84868215766OAI: oai:DiVA.org:kth-103402DiVA: diva2:559923
Note

QC 20130218. Updated from submitted to published.

Available from: 2012-10-11 Created: 2012-10-11 Last updated: 2017-12-07Bibliographically approved
In thesis
1. Nanocomposites made from nanoporous cellulose fibre
Open this publication in new window or tab >>Nanocomposites made from nanoporous cellulose fibre
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis explores how to use the dry nanoporous structure of cellulosic fibres in new types of composite materials. A large effort was also given on how to correctly characterize the structure of fibres where the wet structure has been preserved also in the dry state.

Delignified wood fibres have an open fibrillar structure in their water-swollen state. In the present work, this open fibrillar structure was preserved in the dry state by performing a liquid exchange procedure and the samples were thereafter carefully dried with Ar(g). The samples of never-dried TEMPO-oxidized dissolving pulp had a specific surface area of 130 m2/g in the dry state, as measured using the Brunauer, Emmet, and Teller (BET) Nitrogen gas adsorption method. This open structure was also revealed using field emission scanning electron microscopy (FE-SEM).

The water-swollen and dry open structures were thoroughly characterized for various pulps. A new method for determining the pore size of water-swollen delignified cellulosic fibres is presented. By combining the results from solid state nuclear magnetic resonance NMR, measuring the specific surface area [m2/g] in the water-swollen state, with fibre saturation point (FSP), measuring the pore volume of fibres in water-swollen state [mass water/mass fibre], the average pore size can be determined without the need of assuming a certain pore geometry.

The dry nanoporous structure was then used as a scaffold for in-situ polymerization, to demonstrate how the properties of the fibrils in the fibre wall can be exploited without the need to disintegrate the fibre wall. Both poly(methylmethacrylate) (PMMA) and poly(butylacrylate) (PBA) were successfully used as the polymeric matrix, and both nanocomposites (i.e., fibre/PMMA and fibre/PBA) had a fibre content of approximately 20 w%. The structure of the composites was characterized using SEM and Atomic Force Microscopy (AFM) operated in the phase imaging mode. The AFM results indicate that the cellulose aggregates and polymeric matrix were successfully mixed on a nanoscale, creating a nanocomposite of interpenetrating polymer molecules and cellulose fibrils, rather than a microcomposite, when using microscopic cellulose fibres. The water absorption capacity of the nanocomposites was reduced significantly, indicating that almost all nanopores in the fibre wall were successfully filled with matrix polymer. The mechanical properties were investigated, showing the importance of nanosized reinforcement compared to fibres of micrometer size.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. 28 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2012:43
National Category
Paper, Pulp and Fiber Technology Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-103342 (URN)978-91-7501-479-1 (ISBN)
Presentation
2012-10-26, K1, Teknikringen 56, KTH, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

QC 20121011

Available from: 2012-10-11 Created: 2012-10-10 Last updated: 2012-10-11Bibliographically approved
2. Preparation and characterization of nanoporous cellulose fibres and their use in new material concepts
Open this publication in new window or tab >>Preparation and characterization of nanoporous cellulose fibres and their use in new material concepts
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The overall objective of the work in this thesis is to better utilize the non-collapsed structure of the delignified wood-fibre cell wall in the preparation of new types of materials.

In order to utilize the fibres in new materials, it is crucial to have a well-defined starting material and to know how it reacts to certain treatments of the fibres. A new robust method for measuring the average pore size of water-swollen fibres-rich in cellulose is presented. This method is based on solid-state NMR, which measures the specific surface area [m2/g] of water-swollen samples, and the fibre saturation point (FSP) method, which measures the pore volume [water mass/solid mass] of a water swollen sample. These results can be combined since they are both recorded on water-swollen fibres in the presence of excess water and neither is based on any assumption of any particular pore geometry. Delignifed wood fibres (chemical pulp fibres) have an open fibrillar structure, with approximately 20 nm thick fibril aggregates arranged in a porous structure with a specific surface area of 150 m2/g. This open structure was preserved in the dry state by a liquid-exchange procedure followed by careful drying in argon gas. The dry structure had a specific surface area of 130 m2/g, which implies that the porous structure was preserved in the dry state.

New fibre-basedmaterials were prepared by two different strategies.

The first strategy was to utilize the open nanoporous fibre wall structure for the preparation of nanocomposites. The nanoporous structure was used as a scaffold, allowing monomers to impregnate the structure and to be in-situ polymerized inside the fibre wall pores. Poly(methyl methacrylate) (PMMA) and poly(butylacrylate) (PBA) were synthesized inside the dry nanoporous fibre wall structure, and an epoxy resin was cured in never-dried fibres oxidized to different degrees by TEMPO. The composites prepared thus have a mixture of fibril aggregates and a polymer matrix inside the fibre wall. The structure and performance of the composite materials were evaluated both by high resolution microscopy and mechanically. Characterization of the composite showed that the polymer matrix was successfully formed inside the fibre wall pores. The structural changes caused by oxidation were preserved and utilized for the composite with the epoxy matrix. By tailoring the supramolecular structure of fibres in their water-swollen state, it was hence indeed possible to control the mechanical performance of the nanostructured fibre composites.

The secondbstrategy used to prepare composites was to improve the thermoplastic properties of paper by adding polylactic acid (PLA) latex during the preparation of fibrebsheets. By the addition of PLA-latex, it was possible to form double curved sheets with a nominal strain at break of 21%.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. 57 p.
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2014:41
National Category
Paper, Pulp and Fiber Technology Composite Science and Engineering
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-155530 (URN)978-91-7595-290-1 (ISBN)
Public defence
2014-11-28, F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Funder
Knut and Alice Wallenberg Foundation
Note

QC 20141107

Available from: 2014-11-07 Created: 2014-11-06 Last updated: 2014-11-07Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Larsson, Per TomasWågberg, Lars

Search in DiVA

By author/editor
Svensson, AnnaLarsson, Per TomasSalazar-Alvarez, GermanWågberg, Lars
By organisation
Fibre and Polymer TechnologyWallenberg Wood Science CenterFibre Technology
In the same journal
Carbohydrate Polymers
Polymer Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 316 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