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Publications (10 of 307) Show all publications
Yang, X., Reid, M. S., Olsén, P. & Berglund, L. A. (2020). Eco-Friendly Cellulose Nanofibrils Designed by Nature: Effects from Preserving Native State. ACS Nano, 14(1), 724-735
Open this publication in new window or tab >>Eco-Friendly Cellulose Nanofibrils Designed by Nature: Effects from Preserving Native State
2020 (English)In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 14, no 1, p. 724-735Article in journal (Refereed) Published
Abstract [en]

Cellulose nanofibrils (CNFs) show high modulus and strength and are already used in industrial applications. Mechanical properties of neat CNF films or CNF-polymer matrix nanocomposites are usually much better than for polymer matrix composite films reinforced by clay, graphene, graphene oxide, or carbon nanotubes. In order to obtain small CNF diameter and colloidal stability, chemical modification has so far been necessary, but this increases cost and reduces eco-friendly attributes. In this study, an unmodified holocellulose CNF (Holo-CNF) with small diameter is obtained from mildly peracetic acid delignified wood fibers. CNF is readily defibrillated by low-energy kitchen blender processing. The hemicellulose coating on individual fibrils in the wood plant cell wall is largely preserved in Holo-CNF. This "native" CNF shows well-preserved native fibril structure in terms of length (similar to 2.1 mu m), diameter (<5 nm), high crystallinity, high cellulose molar mass, electronegative charge, and limited mechanical processing damage. The hemicellulose coating contributes mechanical properties and high optical transmittance for CNF nanopaper, which can otherwise only be achieved with chemically modified CNFs. The CNF nanopaper shows superior mechanical properties with a Young's modulus of 21 GPa and an ultimate strength of 320 MPa. Moreover, hemicellulose imparts recyclability from the dried state. Altogether, this native CNF represents a class of colloidally stable, eco-friendly, low-cost CNF of small diameter for large-scale applications of nanopaper and nanomaterials.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2020
Keywords
nanocellulose, hemicellulose, cellulose nanopaper films, redisperse, polymer grafting
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-268775 (URN)10.1021/acsnano.9b07659 (DOI)000510531500063 ()31886646 (PubMedID)2-s2.0-85078763556 (Scopus ID)
Note

QC 20200226

Available from: 2020-02-26 Created: 2020-02-26 Last updated: 2020-02-26Bibliographically approved
Sheng, X., Li, Y., Yang, T., Timmer, B., Willhammar, T., Cheung, O., . . . Sun, L. (2020). Hierarchical micro-reactor as electrodes for water splitting by metal rod tipped carbon nanocapsule self-assembly in carbonized wood. Applied Catalysis B: Environmental, 264, Article ID 118536.
Open this publication in new window or tab >>Hierarchical micro-reactor as electrodes for water splitting by metal rod tipped carbon nanocapsule self-assembly in carbonized wood
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2020 (English)In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 264, article id 118536Article in journal (Refereed) Published
Abstract [en]

Materials design of efficient electrochemical micro-reactors is challenging, although hierarchically structured, self-standing electrodes with catalyst arrays offer promise. Herein, catalyst function in compact micro-reactor electrodes is designed by nanostructural tailoring of carbonized wood for efficient water splitting. Specifically, NiFe rod tipped, N-doped graphitic carbon nanocapsule arrays are self-assembled in hierarchical wood, and the benefit of this unique presentation and its promotive effect on accessibility of the catalyst surfaces is apparent. This report also comprises the first wood based micro-reactor electrodes for electrocatalytic water oxidation demonstrating excellent performance. The overpotential for oxygen evolution reaction was as low as 180 mV for 10 mA cm−2 current density and TOFredox was high at a level of 5.8 s−1 (at 370 mV overpotential). This hierarchical electrode can also work as bifunctional catalyst (both as anodic and as cathodic electrode) for total water splitting with a cell potential of 1.49 V for 10 mA cm−2 in alkaline solution, suggestive of their potential also in other electrochemical applications.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Carbonized wood, Metal rod tipped carbon nanocapsules, Microfluidic electrodes, Oxygen evolution reaction
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-267782 (URN)10.1016/j.apcatb.2019.118536 (DOI)2-s2.0-85076717565 (Scopus ID)
Note

QC 20200304

Available from: 2020-03-04 Created: 2020-03-04 Last updated: 2020-03-04Bibliographically approved
Wu, Q., Mushi, N. E. & Berglund, L. (2020). High-Strength Nanostructured Films Based on Well-Preserved alpha-Chitin Nanofibrils Disintegrated from Insect Cuticles. Biomacromolecules, 21(2), 604-612
Open this publication in new window or tab >>High-Strength Nanostructured Films Based on Well-Preserved alpha-Chitin Nanofibrils Disintegrated from Insect Cuticles
2020 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 21, no 2, p. 604-612Article in journal (Refereed) Published
Abstract [en]

The alpha-chitin nanofibril is an alternative to nanocellulose as a building-block for strong films and other nanomaterials. The hypothesis of high film strength for films based on mildly treated insect cuticles was tested. Fibrils from the cuticle of Ruspolia differens (a long-horned bush cricket grasshopper locally known as senene) are disintegrated by a mild process, subsequently characterized by transmission electron microscopy, NMR, Fourier transform infrared spectroscopy, and XRD, and used to prepare strong and transparent films. A mild process (with 20% NaOH treatment for 2 weeks and at room temperature) was used to largely remove the strongly bound protein associated with chitin. The purpose was to reduce chitin degradation. The native structure of chitin was indeed well preserved and close to the native state, as is supported by data for degree of acetylation, molar mass, crystallinity, and crystallite dimensions. The diameter of the smallest chitin fibrils was as small as 3-7 nm (average 6 nm) with lengths larger than or around 1 mu m. A stable and well -dispersed colloidal chitin fibril suspension in water was achieved. A nanostructured chitin film prepared by filtration showed high optical transmittance (similar to 90%) and very high tensile strength (220 MPa). The high tensile strength was attributed to the well-preserved chitin structure, high intrinsic fibril strength, and high colloidal stability of the fibril suspension. Strong, transparent insect chitin films offer interesting alternatives to nanocellulose films because of different resource origins, surface chemistries, and potential antimicrobial properties.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2020
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-269471 (URN)10.1021/acs.biomac.9b01342 (DOI)000513091100032 ()31742385 (PubMedID)2-s2.0-85076238936 (Scopus ID)
Note

QC 20200310

Available from: 2020-03-10 Created: 2020-03-10 Last updated: 2020-03-10Bibliographically approved
Olsen, P., Herrera, N. & Berglund, L. (2020). Polymer Grafting Inside Wood Cellulose Fibers by Improved Hydroxyl Accessibility from Fiber Swelling. Biomacromolecules, 21(2), 597-603
Open this publication in new window or tab >>Polymer Grafting Inside Wood Cellulose Fibers by Improved Hydroxyl Accessibility from Fiber Swelling
2020 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 21, no 2, p. 597-603Article in journal (Refereed) Published
Abstract [en]

Chemical modification of wood cellulose fibers is important for tailored wood-polymer interfaces, reduced moisture sorption, and novel grades of chemical wood pulp. The present study shows how the reaction solvent system influences hydroxyl accessibility during chemical fiber modification. Surface initiated ring-opening polymerization of e-caprolactone from wood cellulose fibers was investigated in a wide range of solvent systems. The hydrogen bond donor strength of the solvent increased graft density and the amount of grafted polycaprolactone (PCL) on the fiber surface, and on nanoscale fibrils inside the fiber. Specifically, the reaction system with acetic acid as a new, green solvent for cellulose grafting increased graft density 24 times compared to bulk polymerization conditions. The results show relationships between solvent properties, hydroxyl accessibility, and grafting results in cellulosic plant fibers. The study clarifies the opportunities provided by controlling the interior of the cellulosic plant fiber cell wall during chemical modification so that the fiber becomes a swollen cellulose nanofibril gel.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2020
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-269470 (URN)10.1021/acs.biomac.9b01333 (DOI)000513091100031 ()31769663 (PubMedID)2-s2.0-85076508296 (Scopus ID)
Note

QC 20200310

Available from: 2020-03-10 Created: 2020-03-10 Last updated: 2020-03-10Bibliographically approved
Mianehrow, H., Lo Re, G. & Berglund, L. (2020). Strong nanopaperes based on cellulose nanofibrils and graphene oxide. In: ECCM 2018 - 18th European Conference on Composite Materials: . Paper presented at 18th European Conference on Composite Materials, ECCM 2018, 24-28 June 2018, Athens, Greece. Applied Mechanics Laboratory
Open this publication in new window or tab >>Strong nanopaperes based on cellulose nanofibrils and graphene oxide
2020 (English)In: ECCM 2018 - 18th European Conference on Composite Materials, Applied Mechanics Laboratory , 2020Conference paper, Published paper (Refereed)
Abstract [en]

With respect to the importance of high performance bio-based composites, an attempt was made to prepare biocomposites based on cellulose nanofibers (CNF) and Graphene oxide (GO) to study the synergistic effect of their superior properties on the mechanical properties of the resultant biocomposite. Mechanical testing showed the addition of only 0.1 wt% of GO to CNF results in a composite with 17.3 GPa modulus. This effective reinforcement by adding a small amount of GO, shows the efficient stress transfer from CNF to GO that is the result of utilizing large GO sheets with high aspect ratio, effective dispersion of GO in the nanocomposite and the layered structure of the resultant nanocomposite.

Place, publisher, year, edition, pages
Applied Mechanics Laboratory, 2020
Keywords
Biocomposite, Cellulose Nanofibrils, Graphene Oixde, Mechanical properties, Reinforcement
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-267996 (URN)2-s2.0-85077525802 (Scopus ID)9781510896932 (ISBN)
Conference
18th European Conference on Composite Materials, ECCM 2018, 24-28 June 2018, Athens, Greece
Note

QC 20200330

Available from: 2020-03-30 Created: 2020-03-30 Last updated: 2020-03-30Bibliographically approved
Peterson, A., Ostergren, I., Lotsari, A., Venkatesh, A., Thunberg, J., Strom, A., . . . Mueller, C. (2019). Dynamic Nanocellulose Networks for Thermoset-like yet Recyclable Plastics with a High Melt Stiffness and Creep Resistance. Biomacromolecules, 20(10), 3924-3932
Open this publication in new window or tab >>Dynamic Nanocellulose Networks for Thermoset-like yet Recyclable Plastics with a High Melt Stiffness and Creep Resistance
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2019 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, no 10, p. 3924-3932Article in journal (Refereed) Published
Abstract [en]

Many polymers, including polyethylene, feature a relatively low melting point and hence must be cross-linked to make them viable for applications that demand a high stiffness and creep resistance at elevated temperatures. The resulting thermoset plastics cannot be recycled, and therefore alternative materials with a reconfigurable internal network structure are in high demand. Here, we establish that such a thermoset-like yet recyclable material can be realized through the addition of a nanocellulose reinforcing agent. A network consisting of cellulose nanocrystals, nano- or microfibrils imparts many of the characteristics that are usually achieved through chemical cross-linking. For instance, the addition of only 7.5 wt % of either nanocellulose material significantly enhances the melt stiffness of an otherwise molten ethylene-acrylate copolymer by at least 1 order of magnitude. At the same time, the nanocellulose network reduces the melt creep elongation to less than 10%, whereas the neat molten matrix would rupture. At high shear rates, however, the molten composites do not display a significantly higher viscosity than the copolymer matrix, and therefore retain the processability of a thermoplastic material. Repeated re-extrusion at 140 degrees C does not compromise the thermomechanical properties, which indicates a high degree of recyclability. The versatility of dynamic nanocellulose networks is illustrated by 3D printing of a cellulose composite, where the high melt stiffness improves the printability of the resin.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-263355 (URN)10.1021/acs.biomac.9b00993 (DOI)000490658900030 ()31525970 (PubMedID)2-s2.0-85072966263 (Scopus ID)
Note

QC 20191119

Available from: 2019-11-19 Created: 2019-11-19 Last updated: 2019-11-19Bibliographically approved
Vasileva, E., Baitenov, A., Chen, H., Li, Y., Sychugov, I., Yan, M., . . . Popov, S. (2019). Effect of transparent wood on the polarization degree of light. Optics Letters, 44(12), 2962-2965
Open this publication in new window or tab >>Effect of transparent wood on the polarization degree of light
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2019 (English)In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 44, no 12, p. 2962-2965Article in journal (Refereed) Published
Abstract [en]

We report on the study of polarization properties of light propagating through transparent wood (TW), which is an anisotropically scattering medium, and consider two cases: completely polarized and totally unpolarized light. It was demonstrated that scattered light distribution is affected by the polarization state of incident light. Scattering is the most efficient for light polarized parallel to cellulose fibers. Furthermore, unpolarized light becomes partially polarized (with a polarization degree of 50%) after propagating through the TW. In the case of totally polarized incident light, however, the degree of polarization of transmitted light is decreased, in an extreme case to a few percent, and reveals an unusual angular dependence on the material orientation. The internal hierarchical complex structure of the material, in particular cellulose fibrils organized in lamellae, is believed to be responsible for the change of the light polarization degree. It was demonstrated that the depolarization properties are determined by the angle between the polarization of light and the wood fibers, emphasizing the impact of their internal structure, unique for different wood species.

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2019
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-255191 (URN)10.1364/OL.44.002962 (DOI)000471636700005 ()31199356 (PubMedID)2-s2.0-85067943575 (Scopus ID)
Note

QC 20190904

Available from: 2019-09-04 Created: 2019-09-04 Last updated: 2019-09-04Bibliographically approved
Koskela, S., Wang, S., Yang, X., Li, K., Srivastava, V., McKee, L. S., . . . Zhou, Q. (2019). Enzyme-assisted preparation of nanocellulose from wood holocellulose fibers. Paper presented at National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL. AMER CHEMICAL SOC, 257
Open this publication in new window or tab >>Enzyme-assisted preparation of nanocellulose from wood holocellulose fibers
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2019 (English)Other (Other academic)
Place, publisher, year, pages
AMER CHEMICAL SOC, 2019
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-257591 (URN)000478860502553 ()
Conference
National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL
Note

QC 20190925

Available from: 2019-09-25 Created: 2019-09-25 Last updated: 2019-11-11Bibliographically approved
Chen, P., Terenzi, C., Furo, I., Berglund, L. & Wohlert, J. (2019). Heterogeneous dynamics in cellulose from molecular dynamics simulations. Paper presented at National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL. Abstracts of Papers of the American Chemical Society, 257
Open this publication in new window or tab >>Heterogeneous dynamics in cellulose from molecular dynamics simulations
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2019 (English)In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-257590 (URN)000478860502701 ()
Conference
National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL
Note

QC 20190919

Available from: 2019-09-19 Created: 2019-09-19 Last updated: 2019-10-15Bibliographically approved
Yang, X., Berthold, F. & Berglund, L. (2019). High-Density Molded Cellulose Fibers and Transparent Biocomposites Based on Oriented Holocellulose. ACS Applied Materials and Interfaces, 11(10), 10310-10319
Open this publication in new window or tab >>High-Density Molded Cellulose Fibers and Transparent Biocomposites Based on Oriented Holocellulose
2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 10, p. 10310-10319Article in journal (Refereed) Published
Abstract [en]

Ecofriendly materials based on well-preserved and nanostructured wood cellulose fibers are investigated for the purpose of load-bearing applications, where optical transmittance may be advantageous. Wood fibers are subjected to mild delignification, flow orientation, and hot-pressing to form an oriented material of low porosity. The biopolymer composition of the fibers is determined. Their morphology is studied by scanning electron microscopy, cellulose orientation is quantified by X-ray diffraction, and the effect of beating is investigated. Hot-pressed networks are impregnated by a methyl methacrylate monomer and polymerized to form thermoplastic wood fiber/poly(methyl methacrylate) biocomposites. Tensile tests are performed, as well as optical transmittance measurements. Structure-property relationships are discussed. High-density molded fibers from holocellulose have mechanical properties comparable with nanocellulose materials and are recyclable. The thermoplastic matrix biocomposites showed superior mechanical properties (Young's modulus of 20 GPa and ultimate strength of 310 MPa) at a fiber volume fraction of 52%, with high optical transmittance of 90%. The study presents a scalable approach for strong, stiff, and transparent molded fibers/biocomposites.Ecofriendly materials based on well-preserved and nanostructured wood cellulose fibers are investigated for the purpose of load-bearing applications, where optical transmittance may be advantageous. Wood fibers are subjected to mild delignification, flow orientation, and hot-pressing to form an oriented material of low porosity. The biopolymer composition of the fibers is determined. Their morphology is studied by scanning electron microscopy, cellulose orientation is quantified by X-ray diffraction, and the effect of beating is investigated. Hot-pressed networks are impregnated by a methyl methacrylate monomer and polymerized to form thermoplastic wood fiber/poly(methyl methacrylate) biocomposites. Tensile tests are performed, as well as optical transmittance measurements. Structure-property relationships are discussed. High-density molded fibers from holocellulose have mechanical properties comparable with nanocellulose materials and are recyclable. The thermoplastic matrix biocomposites showed superior mechanical properties (Young's modulus of 20 GPa and ultimate strength of 310 MPa) at a fiber volume fraction of 52%, with high optical transmittance of 90%. The study presents a scalable approach for strong, stiff, and transparent molded fibers/biocomposites.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
wood, nanocellulose, high strength, modulus, PMMA, interface
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-248343 (URN)10.1021/acsami.8b22134 (DOI)000461538000072 ()30762342 (PubMedID)2-s2.0-85062458848 (Scopus ID)
Note

QC 20190408

Available from: 2019-04-08 Created: 2019-04-08 Last updated: 2019-10-23Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-5818-2378

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