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
Improved Cellulose Nanofibril Dispersion in Melt-Processed Polycaprolactone Nanocomposites by a Latex-Mediated Interphase and Wet Feeding as LDPE Alternative
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.ORCID iD: 0000-0001-8840-1172
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.ORCID iD: 0000-0002-9572-6888
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.ORCID iD: 0000-0002-7674-0262
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.ORCID iD: 0000-0002-8348-2273
Show others and affiliations
2018 (English)In: ACS Applied Nano Materials, ISSN 2574-0970, Vol. 1, no 6, p. 2669-2677Article in journal (Refereed) Published
Abstract [en]

This work reports the development of a sustainable and green one-step wet-feeding method to prepare tougher and stronger nanocomposites from biodegradable cellulose nanofibrils (CNF)/polycaprolactone (PCL) constituents, compatibilized with reversible addition fragmentation chain transfer-mediated surfactant-free poly(methyl methacrylate) (PMMA) latex nanoparticles. When a PMMA latex is used, a favorable electrostatic interaction between CNF and the latex is obtained, which facilitates mixing of the constituents and hinders CNF agglomeration. The improved dispersion is manifested in significant improvement of mechanical properties compared with the reference material. The tensile tests show much higher modulus (620 MPa) and strength (23 MPa) at 10 wt % CNF content (compared to the neat PCL reference modulus of 240 and 16 MPa strength), while maintaining high level of work to fracture the matrix (7 times higher than the reference nanocomposite without the latex compatibilizer). Rheological analysis showed a strongly increased viscosity as the PMMA latex was added, that is, from a well-dispersed and strongly interacting CNF network in the PCL.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018. Vol. 1, no 6, p. 2669-2677
National Category
Materials Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-241449DOI: 10.1021/acsanm.8b00376ISI: 000461400700029OAI: oai:DiVA.org:kth-241449DiVA, id: diva2:1281459
Note

QC 20190123

Available from: 2019-01-22 Created: 2019-01-22 Last updated: 2019-04-23Bibliographically approved
In thesis
1. Tailored adhesion of PISA-latexes for cellulose modification and new materials
Open this publication in new window or tab >>Tailored adhesion of PISA-latexes for cellulose modification and new materials
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is focused on applying modification chemistry to already known cellulosic substrates from wood (i.e. cellulose nanofibrils, CNFs, and cellulose nanocrystals, CNCs). The modification is needed to overcome the drawbacks with the nanocellulosics alone, such as sensitivity to water (hydrophilicity) and the brittle material properties (however great stiffness). The first aim is to incorporate nanocellulosics into hydrophobic degradable materials of poly(ε-caprolactone) (PCL), resulting in aggregation if not modified. The challenge is to reach high fraction of nanocellulosics, whilst maintaining the flexibility of PCL and improving the properties of the resulting nanocomposite with the corresponding stiffness of the nanocellulosics. The second aim is to increase toughness and strain-at-break for nanocomposite materials of CNF-networks, to increase the plastic deformation equivalent of fossil-based polymeric materials such as polypropylene (PP). Aiming to achieve these goals, the thesis also includes new synthetic strategies of tailored-made set of block copolymers as modifying components. The modifying components, were synthesised by surfactant-free emulsion polymerisation and polymerisation induced self-assembly (PISA), so called PISA-latexes.

Two types of cationic polyelectrolytes, (poly(2-dimethylaminoethy methacrylate) (PDMAEMA) and poly(N-[3-(dimethylamino)propyl] methacrylamide (PDMAPMA)), being the corona of the latex, were synthesised. Followed by chain-extension with different hydrophobic monomers such as methyl methacrylate and butyl methacrylate, making up the core polymer of the resulting PISA-latex. The cationic PISA-latexes show narrow size distributions and the glass transition (Tg) of the core polymer can be varied between -40 °C to 150 °C. The PISA-latexes show strong adhesion to silica and cellulose surfaces as assessed by quartz crystal microbalance (QCM-D). Results also indicate that latexes with Tg below room temperature, considered soft, behave different in the wet state than latexes with Tg above room temperature, considered rigid. The softer latexes form clusters (visualised by imaging with microscopy and atomic force measurements (AFM)) and undergo film formation in the wet state. The latter, shown by colloidal probe measurements using AFM resulting in very large work of adhesion and pull-off forces.

The PISA-latexes compatibilize CNCs and different CNFs with PCL as a matrix polymer, observed by a small increase in stiffness for the final nanocomposites, however not at a level expected by rule-of-mixtures. The promising wet feeding technique results in large increase in stiffness but maintain PCL’s flexibility, above 200% strain-at-break, which is rarely observed for CNF-reinforced nanocomposites. The, in this case, rigid latex facilitate the dispersion of CNFs in the matrix without aggregation, until finally coalescing after processing and possibly giving rise to improved adhesion between CNF and the latex in the matrix, indicated by rheology measurements. Lastly, new nanocomposite films consisting of 75wt% CNF and 25wt% of PISA-latexes were produced and evaluated. The results show that CNF and rigid 100 nm sized PISA-latex, with PMMA core, gives a very tough double network, with strain-at-break above 28%, stiffness of 3.5 GPa and a strength of 110 MPa. These are impressive properties compared to commonly used fossil-based plastic materials.

Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2019. p. 128
Series
TRITA-CBH-FOU ; 2019:7
Keywords
PISA, latex, RAFT, Cellulose Nanofibrils, Cellulose Nanocrystals, Nanocomposites
National Category
Polymer Chemistry
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-241463 (URN)978-91-7873-086-5 (ISBN)
Public defence
2019-02-22, Kollegiesalen, Brinellvägen 8, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20190123

Available from: 2019-01-23 Created: 2019-01-22 Last updated: 2019-05-20Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full text

Authority records BETA

Lo Re, GiadaEngström, JoakimWu, QiongMalmström, EvaGedde, Ulf W.Olsson, RichardBerglund, Lars

Search in DiVA

By author/editor
Lo Re, GiadaEngström, JoakimWu, QiongMalmström, EvaGedde, Ulf W.Olsson, RichardBerglund, Lars
By organisation
BiocompositesCoating TechnologyWallenberg Wood Science CenterPolymeric Materials
Materials Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 8297 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