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
Soft and rigid core latex nanoparticles prepared by RAFT-mediated surfactant-free emulsion polymerization for cellulose modification-a comparative study
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 Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.ORCID iD: 0000-0002-9572-6888
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
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.ORCID iD: 0000-0001-8622-0386
Université de Lyon, Univ Lyon 1, CPE Lyon, CNRS, UMR 5265, C2P2 (Chemistry, Catalysis, Polymers & Processes), Team LCPP Bat 308F, 43 Bd du 11 Novembre 1918, 69616 Villeurbanne, France .
Show others and affiliations
2017 (English)In: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 8, no 6, p. 1061-1073Article in journal (Refereed) Published
Abstract [en]

Latex nanoparticles comprising cationically charged coronas and hydrophobic cores with different glass transition temperatures (Tg) have been prepared by surfactant-free, RAFT-mediated emulsion polymerization, where the particles form through a polymerization-induced self-assembly (PISA) type mechanism. Poly(2-dimethylaminoethyl methacrylate-co-methacrylic acid) (P(DMAEMA-co-MAA)) was utilized as a hydrophilic macroRAFT agent for the polymerization of methyl methacrylate (MMA) or n-butyl methacrylate (nBMA), respectively, resulting in two different latexes, with either a core of high (PMMA) or low (PnBMA) Tg polymer. By varying the molar mass of the hydrophobic block, latexes of different sizes were obtained (DHca. 40-120 nm). The adsorption of the latexes to cellulose model surfaces and cellulose nanofibrils (CNF) was studied using quartz crystal microbalance with dissipation monitoring (QCM-D). The surfaces with adsorbed PnBMA latexes yielded hydrophobic surfaces both before and after annealing, whereas surfaces with adsorbed PMMA latex became hydrophobic only after annealing, clearly showing the influence of the Tg of the core. The latexes were also used to modify macroscopic cellulose in the form of filter papers. Similar to the CNF surfaces, no annealing was required to achieve hydrophobic surfaces with PnBMA latexes. Finally, nanocomposites of CNF and the polymer nanoparticles were prepared through a one-pot mixing procedure. It was found that the largest synthesized PMMA latex (120 nm) facilitated a more strainable CNF network at 50% relative humidity, with a nearly 200% increase in strain at break compared to the neat CNF reference film as well as to the composite films with PnBMA latexes or to the smaller sized PMMA latexes. This difference was attributed to the spherical shape and rigidity of the large PMMA latex nanoparticles during composite formation. This highly interesting result should indeed be considered in the future design of novel biocomposites.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017. Vol. 8, no 6, p. 1061-1073
National Category
Polymer Technologies
Identifiers
URN: urn:nbn:se:kth:diva-208109DOI: 10.1039/c6py01904hISI: 000395539800012Scopus ID: 2-s2.0-85011827572OAI: oai:DiVA.org:kth-208109DiVA, id: diva2:1106190
Funder
Knut and Alice Wallenberg Foundation
Note

QC 20170607

Available from: 2017-06-07 Created: 2017-06-07 Last updated: 2019-01-23Bibliographically 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: 2019-01-23Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Authority records BETA

Engström, JoakimHatton, FionaWågberg, LarsMalmström, Eva

Search in DiVA

By author/editor
Engström, JoakimHatton, FionaWågberg, LarsMalmström, EvaCarlmark, Anna
By organisation
Fibre and Polymer TechnologyWallenberg Wood Science CenterWallenberg Wood Science Center
In the same journal
Polymer Chemistry
Polymer Technologies

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 516 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