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Publications (10 of 40) Show all publications
Kusano, Y., Madsen, B., Berglund, L., Aitomäki, Y. & Oksman, K. (2018). Dielectric barrier discharge plasma treatment of cellulose nanofibre surfaces. Surface Engineering, 34(11), 825-831
Open this publication in new window or tab >>Dielectric barrier discharge plasma treatment of cellulose nanofibre surfaces
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2018 (English)In: Surface Engineering, ISSN 0267-0844, E-ISSN 1743-2944, Vol. 34, no 11, p. 825-831Article in journal (Refereed) Published
Abstract [en]

Dielectric barrier discharge plasma treatment was applied to modify cellulose nanofibre (CNF) surfaces with and without ultrasonic irradiation. The plasma treatment improved the wetting by deionised water and glycerol, and increased the contents of oxygen, carbonyl group, and carboxyl group on the nanofibre surface. Ultrasonic irradiation further enhanced the wetting and oxidation of the nanofibre coating. Scanning electron microscopic observations showed skeleton-like features on the plasma-treated surface, indicating preferential etching of weaker domains, such as low-molecular weight domains and amorphous phases. Ultrasonic irradiation also improved the uniformity of the treatment. Altogether, it is demonstrated that atmospheric pressure plasma treatment is a promising technique to modify the CNF surface before composite processing.

Place, publisher, year, edition, pages
Taylor & Francis, 2018
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-63996 (URN)10.1080/02670844.2017.1334411 (DOI)000443914700004 ()2-s2.0-85020257445 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-10-08 (johcin)

Available from: 2017-06-14 Created: 2017-06-14 Last updated: 2018-10-08Bibliographically approved
Hooshmand, S., Aitomäki, Y., Berglund, L., Mathew, A. P. & Oksman, K. (2017). Enhanced alignment and mechanical properties through the use of hydroxyethyl cellulose in solvent-free native cellulose spun filaments. Composites Science And Technology, 150, 79-86
Open this publication in new window or tab >>Enhanced alignment and mechanical properties through the use of hydroxyethyl cellulose in solvent-free native cellulose spun filaments
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2017 (English)In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 150, p. 79-86Article in journal (Refereed) Published
Abstract [en]

In this study, the addition of hydroxyethyl cellulose (HEC) in cellulose nanofiber filaments is shown to improve the solvent-free processing and mechanical properties of these biobased fibers as well as their compatibility with epoxy. An aqueous dope of cellulose nanofiber (CNF) with HEC was spun and the resulting filaments cold-drawn. The HEC increased the wet strength of the dope allowing stable spinning of low concentrations of CNF. These lower concentrations promote nanofiber alignment which is further improved by cold-drawing. Alignment improves the modulus and strength and an increase of over 70% compared to the as-spun CNF only filaments was achieved. HEC also decreases hydrophilicity thus increasing slightly the interfacial shear strength of the filaments with epoxy resin. The result is continuous biobased fibers with improved epoxy compatibility that can be prepared in an upscalable and environmentally friendly way. Further optimization is expected to increase draw ratio and consequently mechanical properties.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-65051 (URN)10.1016/j.compscitech.2017.07.011 (DOI)000412041300008 ()2-s2.0-85024383663 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-08-14 (andbra)

Available from: 2017-08-14 Created: 2017-08-14 Last updated: 2018-03-05Bibliographically approved
Hassan, M. L., Abou-zeid, R. E., Hassan, E. A., Berglund, L., Aitomäki, Y. & Oksman, K. (2017). Membranes based on cellulose nanofibers and activated carbon for removal of Escherichia coli bacteria from water. Polymers, 9(8), Article ID 335.
Open this publication in new window or tab >>Membranes based on cellulose nanofibers and activated carbon for removal of Escherichia coli bacteria from water
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2017 (English)In: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 9, no 8, article id 335Article in journal (Refereed) Published
Abstract [en]

Cellulosic nanomaterials are potential candidates in different areas, especially in water treatment. In the current work, palm fruit stalks cellulose nanofibers (CNF), TEMPO-oxidized CNF (OCNF), and activated carbon (AC) were used to make thin film membranes for removal of E. coli bacteria from water. Two types of layered membranes were produced: a single layer setup of crosslinked CNF and a two-layer setup of AC/OCNF (bottom) and crosslinked CNF (up) on hardened filter paper. The prepared membranes were evaluated regarding their microstructure and layers thickness using scanning electron microscopy (SEM). Water flux and rejection of E. coli bacteria was tested using dead end stirred cells at 1 MPa pressure. Thickness of the cosslinked CNF layer in both types of membranes was about 0.75 micron. The results showed that exchanging water by isopropyl alcohol before drying increased porosity of membranes, and thus resulted in increasing pure water flux and flux of bacteria suspension. The two-layer AC/OCNF/CNF membrane had much higher water flux than the single layer CNF due to higher porosity seen on the surface of the former. Both types of membranes showed high capability of removing E. coli bacteria (rejection ~96–99%) with slightly higher efficiency for the AC/OCNF/CNF membrane than CNF membrane. AC/OCNF/CNF membrane also showed resistance against growth of E. coli and S. aureus bacteria on the upper CNF surface while the single layer CNF membrane did not show resistance against growth of the aforementioned bacteria

Place, publisher, year, edition, pages
Basel: MDPI, 2017
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-65105 (URN)10.3390/polym9080335 (DOI)000408747000032 ()2-s2.0-85026744622 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-08-15 (andbra)

Available from: 2017-08-15 Created: 2017-08-15 Last updated: 2018-11-26Bibliographically approved
Berglund, L., Anugwom, I., Hedenström, M., Aitomäki, Y., Mikkola, J.-P. & Oksman, K. (2017). Switchable ionic liquids enable efficient nanofibrillation of wood pulp. Cellulose (London), 24(8), 3265-3279
Open this publication in new window or tab >>Switchable ionic liquids enable efficient nanofibrillation of wood pulp
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2017 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, no 8, p. 3265-3279Article in journal (Refereed) Published
Abstract [en]

Use of switchable ionic liquid (SIL) pulp offers an efficient and greener technology to produce nanofibers via ultrafine grinding. In this study, we demonstrate that SIL pulp opens up a mechanically efficient route to the nanofibrillation of wood pulp, thus providing both a low cost and chemically benign route to the production of cellulose nanofibers. The degree of fibrillation during the process was evaluated by viscosity and optical microscopy of SIL treated, bleached SIL treated and a reference pulp. Furthermore, films were prepared from the fibrillated material for characterization and tensile testing. It was observed that substantially improved mechanical properties were attained as a result of the grinding process, thus signifying nanofibrillation. Both SIL treated and bleached SIL treated pulps were fibrillated into nanofibers with fiber diameters below 15 nm thus forming networks of hydrophilic nature with an intact crystalline structure. Notably, it was found that the SIL pulp could be fibrillated more efficiently than traditional pulp since nanofibers could be produced with more than 30% less energy when compared to the reference pulp. Additionally, bleaching reduced the energy demand by further 16%. The study demonstrated that this switchable ionic liquid treatment has considerable potential in the commercial production of nanofibers due to the increased efficiency in fibrillation.

Place, publisher, year, edition, pages
Springer, 2017
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-63803 (URN)10.1007/s10570-017-1354-2 (DOI)000405612000013 ()2-s2.0-85020247731 (Scopus ID)
Note

Validerad;2017;Nivå 2;2017-08-10 (rokbeg)

Available from: 2017-06-08 Created: 2017-06-08 Last updated: 2019-09-19Bibliographically approved
Zhou, X., Sethi, J., Geng, S., Berglund, L., Frisk, N., Aitomäki, Y., . . . Oksman, K. (2016). Dispersion and reinforcing effect of carrot nanofibers on biopolyurethane foams (ed.). Materials & design, 110, 526-531
Open this publication in new window or tab >>Dispersion and reinforcing effect of carrot nanofibers on biopolyurethane foams
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2016 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 110, p. 526-531Article in journal (Refereed) Published
Abstract [en]

In this study, carrot nanofibers (CNF) were used to enhance the performance of biobased castor oil polyol polyurethane nanocomposite foams. A method of dispersing CNF in the polyol was developed and the foam characteristics and CNF reinforcing effect were studied. Co-solvent-assisted mixing resulted in well-dispersed CNF in the polyol, and foams with 0.25, 0.5 and 1 phr CNF content were prepared. The reinforced nanocomposite foams displayed a narrow cell size distribution and the compressive strength and modulus were significantly elevated and the best compressive strength and modulus were reached with 0.5 phr CNF. Similarly, the modulus of the solid material was also significantly increased based on theoretical calculations. When comparing the foam performance, compressive strength and stiffness as a function of the density, the nanocomposite foams performs as commercial rigid PU foam with a closed cell structure. These results are very promising and we believe that these foams are excellent core materials for lightweight sandwich composites.

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-3617 (URN)10.1016/j.matdes.2016.08.033 (DOI)000385600800058 ()2-s2.0-84982179497 (Scopus ID)1705190f-7be1-4744-b5f9-9d35d898a489 (Local ID)1705190f-7be1-4744-b5f9-9d35d898a489 (Archive number)1705190f-7be1-4744-b5f9-9d35d898a489 (OAI)
Note

Validerad; 2016; Nivå 2; 20160815 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Kusano, Y., Berglund, L., Aitomäki, Y., Oksman, K. & Madsen, B. (2016). Gliding arc surface modification of carrot nanofibre coating: Perspective for composite processing. Paper presented at 37th Risø International Symposium on Materials Science, 5 - 8 September 2016, Technical University of Denmark Risø Campus, Roskilde. IOP Conference Series: Materials Science and Engineering, 139, Article ID 012027.
Open this publication in new window or tab >>Gliding arc surface modification of carrot nanofibre coating: Perspective for composite processing
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2016 (English)In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 139, article id 012027Article in journal (Refereed) Published
Abstract [en]

Surfaces of carrot nanofibre coatings were modified by a gliding arc in atmospheric pressure air. The treatment strengthened wetting of deionized water and glycerol, increased an oxygen content, C-O and C=O, and moderately roughened the surfaces. In the perspective of composite materials, these changes to the nanofibres can potentially improve their processability when they are to be impregnated with a polymeric matrix. However, longer exposure to the gliding arc reduced oxidation and roughness of the surface, and thus there exists an optimum condition to achieve good wetting to solvents

National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-60055 (URN)10.1088/1757-899X/139/1/012027 (DOI)000392730000027 ()2-s2.0-84989299877 (Scopus ID)
Conference
37th Risø International Symposium on Materials Science, 5 - 8 September 2016, Technical University of Denmark Risø Campus, Roskilde
Note

2017-02-23 (andbra);Konferensartikel i tidskrift

Available from: 2016-10-31 Created: 2016-10-31 Last updated: 2018-07-10Bibliographically approved
Aitomäki, Y., Westin, M. & Oksman, K. (2016). Hydrogel state impregnation of cellulose fibre-phenol composites: effects of fibre size distribution (ed.). In: (Ed.), ECCM 2016: Proceeding of the 17th European Conference on Composite Materials. Paper presented at 17th European conference on composite materials, ECCM-17, Munich, Germany, 26-30 June 2016. European Conference on Composite Materials
Open this publication in new window or tab >>Hydrogel state impregnation of cellulose fibre-phenol composites: effects of fibre size distribution
2016 (English)In: ECCM 2016: Proceeding of the 17th European Conference on Composite Materials, European Conference on Composite Materials , 2016Conference paper, Published paper (Refereed)
Abstract [en]

Whilst it has been well established that cellulose nanofibres (CNF) networks produce films that have high stiffness and strength, they are difficult to impregnate. Investigated in this study is whether by controlling the degree of nanofibrillation of cellulose, composites based on micro- and nano-size cellulose fibres can be made that are more easily manufactured and have better impregnation than solely cellulose nano-fibre based composites. To evaluate this, cellulose at different stages of ultrafine grinding, extracted at time intervals of 30, 60 and 290 mins, were used to make composites. To achieve good impregnation a novel strategy was used based on impregnation with phenol resin whilst the fibrillated cellulose is in a hydrogel state. The composites were subsequently dried and consolidated by hot press. The current results show that this method of impregnation is successful and the phenol matrix greatly improves the properties of the cellulose with a low degree of fibrillation. In general, as the degree of fibrillation and the proportion of nanofibres increases, the mechanical properties of the networks and their composites increase. The addition of the matrix appears to restrict the deformation of CNF network, increasing the modulus and yield strength but decreasing the ultimate strength. The method also appears to restrict the consolidation and voids remain in the composite, which reduces the modulus when compared to theoretical maximum values for this material. More work on the consolidation process is necessary to achieve the full potential of these composites.

Place, publisher, year, edition, pages
European Conference on Composite Materials, 2016
Keywords
nanofibres, impregnation, phenol, network behaviour, fibrillation, Materials science - Other processing/assembly, Teknisk materialvetenskap - Övrig bearbetning/sammanfogning
National Category
Bio Materials
Research subject
Wood and Bionanocomposites; Smart machines and materials (AERI)
Identifiers
urn:nbn:se:ltu:diva-29908 (URN)2-s2.0-85017671151 (Scopus ID)388103c5-2224-45e5-8e38-95a1df306d90 (Local ID)978-3-00-053387-7 (ISBN)388103c5-2224-45e5-8e38-95a1df306d90 (Archive number)388103c5-2224-45e5-8e38-95a1df306d90 (OAI)
Conference
17th European conference on composite materials, ECCM-17, Munich, Germany, 26-30 June 2016
Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Aitomäki, Y., Berglund, L., Noël, M., Linder, T., Löfqvist, T. & Oksman, K. (2016). Light scattering in cellulose nanofibre suspensions: Model and experiments (ed.). In: (Ed.), (Ed.), Computers in Chemistry Proceeding from ACS National Meeting San Diego: Proceeding from ACS National Meeting San Diego. Paper presented at American Chemical Society (ACS) National Meeting & Exposition : 13/03/2016 - 17/03/2016 (pp. 122). : American Chemical Society (ACS), Article ID CELL 235.
Open this publication in new window or tab >>Light scattering in cellulose nanofibre suspensions: Model and experiments
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2016 (English)In: Computers in Chemistry Proceeding from ACS National Meeting San Diego: Proceeding from ACS National Meeting San Diego, American Chemical Society (ACS), 2016, p. 122-, article id CELL 235Conference paper, Meeting abstract (Other academic)
Abstract [en]

Here light scattering theory is used to assess the size distribution in a suspension of cellulose as it is fibrillated from micro-scaled to nano-scaled fibres. A model based on Monte carlo simulations of the scattering of photons by different sizes of cellulose fibres was used to predict the UV-IF spectrum of the suspensions. Bleached cellulose hardwood pulp was tested and compared to the visually transparent tempo-oxidised hardwood cellulose nanofibres (CNF) suspension. The theoretical results show that different diameter size classes exhibit very different scattering patterns. These classes could be identified in the experimental results and used to establish the size class dominating the suspension. A comparison to AFM/microscope size distribution was made and the results indicated that using the UV-IF light scattering spectrum maybe more reliable that size distribution measurement using AFM and microscopy on dried CNF samples. The UV-IF spectrum measurement combined with the theoretical prediction can be used even at this initial stage of development of this model to assess the degree of fibrillation when processing CNF.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2016
National Category
Bio Materials Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Wood and Bionanocomposites; Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-27433 (URN)0e1f8cb1-032d-4e71-956c-b2aca7925036 (Local ID)0e1f8cb1-032d-4e71-956c-b2aca7925036 (Archive number)0e1f8cb1-032d-4e71-956c-b2aca7925036 (OAI)
Conference
American Chemical Society (ACS) National Meeting & Exposition : 13/03/2016 - 17/03/2016
Note
Godkänd; 2016; 20160418 (aitomaki)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Aitomäki, Y., Westin, M., Korpimäki, J. & Oksman, K. (2016). Nanofibre distribution in composites manufactured with epoxy reinforced with nanofibrillated cellulose: model prediction and verification. Paper presented at 37th Risø International Symposium on Materials Science, 5 - 8 September 2016, Technical University of Denmark Risø Campus, Roskilde. IOP Conference Series: Materials Science and Engineering, 139, Article ID 012011.
Open this publication in new window or tab >>Nanofibre distribution in composites manufactured with epoxy reinforced with nanofibrillated cellulose: model prediction and verification
2016 (English)In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 139, article id 012011Article in journal (Refereed) Published
Abstract [en]

In this study a model based on simple scattering is developed and used to predict the distribution of nanofibrillated cellulose in composites manufactured by resin transfer moulding (RTM) where the resin contains nanofibres. The model is a Monte Carlo based simulation where nanofibres are randomly chosen from probability density functions for length, diameter and orientation. Their movements are then tracked as they advance through a random arrangement of fibres in defined fibre bundles. The results of the model show that the fabric filters the nanofibres within the first 20 µm unless clear inter-bundle channels are available. The volume fraction of the fabric fibres, flow velocity and size of nanofibre influence this to some extent. To verify the model, an epoxy with 0.5 wt.% Kraft Birch nanofibres was made through a solvent exchange route and stained with a colouring agent. This was infused into a glass fibre fabric using an RTM process. The experimental results confirmed the filtering of the nanofibres by the fibre bundles and their penetration in the fabric via the inter-bundle channels. Hence, the model is a useful tool for visualising the distribution of the nanofibres in composites in this manufacturing process.

National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-59576 (URN)10.1088/1757-899X/139/1/012011 (DOI)000392730000011 ()2-s2.0-84989329177 (Scopus ID)
Conference
37th Risø International Symposium on Materials Science, 5 - 8 September 2016, Technical University of Denmark Risø Campus, Roskilde
Note

2017-02-23 (andbra);Konferensartikel i tidskrift

Available from: 2016-10-07 Created: 2016-10-07 Last updated: 2018-07-10Bibliographically approved
Berglund, L., Noël, M., Aitomäki, Y., Öman, T. & Oksman, K. (2016). Production potential of cellulose nanofibers from industrial residues: Efficiency and nanofiber characteristics (ed.). Industrial crops and products (Print), 92, 84-92
Open this publication in new window or tab >>Production potential of cellulose nanofibers from industrial residues: Efficiency and nanofiber characteristics
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2016 (English)In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 92, p. 84-92Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to evaluate the production potential of cellulose nanofibers from two different industrial bio-residues: wastes from the juice industry (carrot) and the beer brewing process (BSG). The mechanical separation of the cellulose nanofibers was by ultrafine grinding. X-ray diffraction (XRD) and Raman spectroscopy revealed that the materials were mechanically isolated without significantly affecting their crystallinity. The carrot residue was more easily bleached and consumed less energy during grinding, using only 0.9 kWh/kg compared to 21 kWh/kg for the BSG. The carrot residue also had a 10% higher yield than the BSG. Moreover, the dried nanofiber networks showed high mechanical properties, with an average modulus and strength of 12.9 GPa and 210 MPa, respectively, thus indicating a homogeneous nanosize distribution. The study showed that carrot residue has great potential for the industrial production of cellulose nanofibers due to its high quality, processing efficiency, and low raw material cost

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-15472 (URN)10.1016/j.indcrop.2016.08.003 (DOI)000383821200011 ()2-s2.0-84981234074 (Scopus ID)efda8f84-abf4-42da-9c15-95ea7b63b56e (Local ID)efda8f84-abf4-42da-9c15-95ea7b63b56e (Archive number)efda8f84-abf4-42da-9c15-95ea7b63b56e (OAI)
Note

Validerad; 2016; Nivå 2; 20160815 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2019-09-19Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-2388-3358

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