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Salajkova, Michaela
Publications (3 of 3) Show all publications
Medina, L., Ansari, F., Carosio, F., Salajkova, M. & Berglund, L. (2019). Nanocomposites from Clay, Cellulose Nanofibrils, and Epoxy with Improved Moisture Stability for Coatings and Semi-Structural Applications. ACS Applied Nano Materials
Open this publication in new window or tab >>Nanocomposites from Clay, Cellulose Nanofibrils, and Epoxy with Improved Moisture Stability for Coatings and Semi-Structural Applications
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2019 (English)In: ACS Applied Nano Materials, E-ISSN 2574-0970Article in journal (Refereed) Published
Abstract [en]

A new type of high reinforcement content clay-cellulose-thermoset nanocomposite was proposed, where epoxy precursors diffused into a wet porous clay-nanocellulose mat, followed by curing. The processing concept was scaled to > 200 µm thickness composites, the mechanical properties were high for nanocomposites and the materials showed better tensile properties at 90% RH compared with typical nanocellulose materials. The nanostructure and phase distributions were studied using transmission electron microscopy; Young’s modulus, yield strength, ultimate strength and ductility were determined as well as moisture sorption, fire retardancy and oxygen barrier properties. Clay and cellulose contents were varied, as well as the epoxy content. Epoxy had favorable effects on moisture stability, and also improved reinforcement effects at low reinforcement content. More homogeneous nano- and mesoscale epoxy distribution is still required for further property improvements. The materials constitute a new type of three-phase nanocomposites, of interest as coatings, films and as laminated composites for semi-structural applications.

Keywords
biocomposite, nanocellulose, mechanical, montmorillonite, fire
National Category
Composite Science and Engineering Paper, Pulp and Fiber Technology Nano Technology Materials Chemistry
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-249724 (URN)10.1021/acsanm.9b00459 (DOI)
Funder
Swedish Foundation for Strategic Research , RMA11-0065Knut and Alice Wallenberg Foundation
Note

QC 20190520

Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2019-05-20Bibliographically approved
Morimune-Moriya, S., Salajkova, M., Zhou, Q., Nishino, T. & Berglund, L. A. (2018). Reinforcement Effects from Nanodiamond in Cellulose Nanofibril Films. Biomacromolecules, 19(7), 2423-2431
Open this publication in new window or tab >>Reinforcement Effects from Nanodiamond in Cellulose Nanofibril Films
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2018 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, no 7, p. 2423-2431Article in journal (Refereed) Published
Abstract [en]

Although research on nanopaper structures from cellulose nanofibrils (CNFs) is well established, the mechanical behavior is not well understood, especially not when CNF is combined with hard nanoparticles. Cationic CNF (Q-CNF) was prepared and successfully decorated by anionic nanodiamond (ND) nanoparticles in hydrocolloidal form. The Q-CNF/ND nanocomposites were filtered from a hydrocolloid and dried. Unlike many other carbon nano composites, the QCNF/ND nanocomposites were optically transparent. Reinforcement effects from the nanodiamond were remarkable, such as Young's modulus (9.8 -> 16.6 GPa) and tensile strength (209.5 -> 277.5 MPa) at a content of only 1.9% v/v of ND, and the reinforcement mechanisms are discussed. Strong effects on CNF network deformation mechanisms were revealed by loading unloading experiments. Scratch hardness also increased strongly with increased addition of ND.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-232787 (URN)10.1021/acs.biomac.8b00010 (DOI)000438470800007 ()29620880 (PubMedID)2-s2.0-85049752914 (Scopus ID)
Note

QC 20180806

Available from: 2018-08-06 Created: 2018-08-06 Last updated: 2018-08-06Bibliographically approved
Ansari, F., Salajkova, M., Zhou, Q. & Berglund, L. (2015). Cellulose nanocomposites - Controlling dispersion and material properties through nanocellulose surface modification. In: ICCM International Conferences on Composite Materials: . Paper presented at 20th International Conference on Composite Materials, ICCM 2015, 19 July 2015 through 24 July 2015. International Committee on Composite Materials
Open this publication in new window or tab >>Cellulose nanocomposites - Controlling dispersion and material properties through nanocellulose surface modification
2015 (English)In: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2015Conference paper, Published paper (Refereed)
Abstract [en]

The use of cellulosic nanofibers as reinforcement in polymer composites offers great advantages over their petroleum counterparts. Apart from being strong, stiff and low density; they are obtained from naturally occurring resources and as such are favorable from an environmental point of view. A major problem while studying nanomaterials is their tendency to agglomerate, thus leading to inhomogeneous distribution within the polymer matrix. This often results in stress concentrations in the matrix rich regions when the material is subjected to load and therefore, limits the potential application of these materials. A common approach to circumvent this is by surface modification, which facilitates the dispersion in non-polar matrices. An environmental friendly approach, inspired by clay chemistry, was used to functionalize the CNC surface. It was shown that the CNC could be modified in a rather convenient way to attach a variety of functional groups on the surface. Primarily, the problem of cellulose nanocrystal (CNC) distribution in a hydrophobic polymer matrix is investigated. Composites prepared from modified CNC were studied and compared with unmodified CNC. The distribution of the CNC is carefully monitored at different stages via UV-Vis spectroscopy and scanning electron microscopy (SEM). The mechanical properties of the resulting materials were characterized by dynamic mechanical as well as uniaxial tensile tests. It was shown that a homogeneous distribution of the CNC exposes a tremendous amount of surface area to interact with the matrix. In such a case, the stress transfer is much more efficient and perhaps, the matrix behavior is modified, which leads to significant improvements in the mechanical properties.

Place, publisher, year, edition, pages
International Committee on Composite Materials, 2015
Keywords
Cellulose Nanocomposites, Mechanical Performance, Surface modification
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-236910 (URN)2-s2.0-85053152012 (Scopus ID)
Conference
20th International Conference on Composite Materials, ICCM 2015, 19 July 2015 through 24 July 2015
Note

QC 20181211

Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-11Bibliographically approved
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