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Jungstedt, E., Tavares da Costa, M. V., Östlund, S. & Berglund, L. (2024). On the high fracture toughness of wood and polymer-filled wood composites – Crack deflection analysis for materials design. Engineering Fracture Mechanics, 300, Article ID 109994.
Open this publication in new window or tab >>On the high fracture toughness of wood and polymer-filled wood composites – Crack deflection analysis for materials design
2024 (English)In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 300, article id 109994Article in journal (Refereed) Published
Abstract [en]

Cracks oriented in the toughest direction across the grain of wood (0°) tend to deflect at 90° to the precrack rather than extending in 0° direction. Fracture toughness data across the grain are therefore difficult to interpret. Crack growth mechanisms and effects from replacing wood pore space with a polymer are investigated. Crack growth is analyzed in four-point bending fracture mechanics specimens of birch and two different polymer-filled birch composites using strain-field measurements and finite element analysis (FEA). Calibrated cohesive zone models in both precrack and 90°-directions describe fracture process zone properties in orthotropic FEA-models. Conditions for 0° crack penetration versus 90° crack deflection are analyzed based on cohesive zone properties. Stable, subcritical crack deflection takes place at low load, reduces crack tip stress concentration, and contributes to high structural toughness, provided the 90° toughness is not too low. Polymer-filled neat birch composites have the best structural toughness properties in the present investigation, since 90° toughness is not compromised by any chemical treatment.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
Biocomposites, Cohesive zone modeling, Crack deflection, Fracture toughness, Materials design
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-344321 (URN)10.1016/j.engfracmech.2024.109994 (DOI)001203172200001 ()2-s2.0-85186758685 (Scopus ID)
Note

QC 20240314

Available from: 2024-03-13 Created: 2024-03-13 Last updated: 2024-04-29Bibliographically approved
Mastantuoni, G. G., Tran, V. C., Garemark, J., Dreimol, C. H., Engquist, I., Berglund, L. & Zhou, Q. (2024). Rationally designed conductive wood with mechanoresponsive electrical resistance. Composites. Part A, Applied science and manufacturing, 178, Article ID 107970.
Open this publication in new window or tab >>Rationally designed conductive wood with mechanoresponsive electrical resistance
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2024 (English)In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 178, article id 107970Article in journal (Refereed) Published
Abstract [en]

Porous cellular foams, combining lightweight, high strength, and compressibility, hold great promise in a wide range of advanced applications. Here, the native structure of pine wood was modified by in-situ lignin sulfonation and unidirectional freezing, resulting in an alveolate structure inside the wood cell wall with arrays of sub-100 nm channels. The obtained wood foam exhibited highly enhanced permeability while retaining the native cellular arrangement and high lignin and hemicellulose content. Such engineered cellular foam contributed to superior mechanical performance with compressive strength of 9 MPa and Young's modulus of 344 MPa in the longitudinal direction. The high porosity allowed homogeneous infiltration of conductive polymer PEDOT:PSS inside the wood cell wall. The resulting composite exhibited high conductivity, sponge-like compressibility and the ability to modulate electrical resistance in a reversible manner in the radial direction. This rationally designed conductive wood demonstrated potential in durable and ultrasensitive pressure-responsive devices and strain sensors.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
A Foams, A Multifunctional composites, B Electrical properties, B Mechanical properties
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-342379 (URN)10.1016/j.compositesa.2023.107970 (DOI)2-s2.0-85181932666 (Scopus ID)
Note

Not duplicate with DiVA 1789673

QC 20240122

Available from: 2024-01-17 Created: 2024-01-17 Last updated: 2024-01-22Bibliographically approved
Chen, B., Montanari, C., Popov, S. & Berglund, L. (2023). A distortion-map-based method for morphology generation in multi-phase materials - application to wood. Composites Science And Technology, 244, Article ID 110262.
Open this publication in new window or tab >>A distortion-map-based method for morphology generation in multi-phase materials - application to wood
2023 (English)In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 244, article id 110262Article in journal (Refereed) Published
Abstract [en]

Increased use of multi-phase, wood-based biocomposites may contribute to sustainable development. The porous microstructure offers unique possibilities for modification, but global properties are often predicted based on simplified unit cells and homogenization. For materials design, simulations based on complex 3D microstructures with statistical variability are alternatives to better understanding physical properties. Parametric models are developed in a distortion-map-based method to represent 3D wood microstructures. Basic structures of uniform tubular cells and other features are generated followed by distortion mapping. These maps are highly adaptable and can generate realistic features and variability. Fibers, vessels, and ray cells are realistically distributed. The models are realistic, versatile, and scalable, as well as can be used to simulate the mechanical, optical, and hydrodynamic properties of complex composites. The model is promising for generating large sets of data to train deep learning networks for multi-physics research.

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Biocomposites (A), Material modeling (C), Representative volume element (RVE) (C)
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-338071 (URN)10.1016/j.compscitech.2023.110262 (DOI)001097678400001 ()2-s2.0-85172738375 (Scopus ID)
Note

QC 20231013

Available from: 2023-10-13 Created: 2023-10-13 Last updated: 2023-12-05Bibliographically approved
Koskela, S., Wang, S., Li, L., Zha, L., Berglund, L. & Zhou, Q. (2023). An Oxidative Enzyme Boosting Mechanical and Optical Performance of Densified Wood Films. Small, 19(17), Article ID 2205056.
Open this publication in new window or tab >>An Oxidative Enzyme Boosting Mechanical and Optical Performance of Densified Wood Films
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2023 (English)In: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 19, no 17, article id 2205056Article in journal (Refereed) Published
Abstract [en]

Nature has evolved elegant ways to alter the wood cell wall structure through carbohydrate-active enzymes, offering environmentally friendly solutions to tailor the microstructure of wood for high-performance materials. In this work, the cell wall structure of delignified wood is modified under mild reaction conditions using an oxidative enzyme, lytic polysaccharide monooxygenase (LPMO). LPMO oxidation results in nanofibrillation of cellulose microfibril bundles inside the wood cell wall, allowing densification of delignified wood under ambient conditions and low pressure into transparent anisotropic films. The enzymatic nanofibrillation facilitates microfibril fusion and enhances the adhesion between the adjacent wood fiber cells during densification process, thereby significantly improving the mechanical performance of the films in both longitudinal and transverse directions. These results improve the understanding of LPMO-induced microstructural changes in wood and offer an environmentally friendly alternative for harsh chemical treatments and energy-intensive densification processes thus representing a significant advance in sustainable production of high-performance wood-derived materials.

Place, publisher, year, edition, pages
Wiley, 2023
Keywords
cellulose microfibrils, densified wood, lytic polysaccharide monooxygenase, mechanical properties, wood cell walls
National Category
Wood Science Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-330033 (URN)10.1002/smll.202205056 (DOI)000919095100001 ()36703510 (PubMedID)2-s2.0-85147307840 (Scopus ID)
Note

QC 20230627

Available from: 2023-06-27 Created: 2023-06-27 Last updated: 2023-06-27Bibliographically approved
Samanta, P., Samanta, A., Maddalena, L., Carosio, F., Gao, Y., Montanari, C., . . . Li, Y. (2023). Coloration and Fire Retardancy of Transparent Wood Composites by Metal Ions. ACS Applied Materials and Interfaces, 15(50), 58850-58860
Open this publication in new window or tab >>Coloration and Fire Retardancy of Transparent Wood Composites by Metal Ions
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2023 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 15, no 50, p. 58850-58860Article in journal (Refereed) Published
Abstract [en]

Transparent wood composites (TWs) offer the possibility of unique coloration effects. A colored transparent wood composite (C-TW) with enhanced fire retardancy was impregnated by metal ion solutions, followed by methyl methacrylate (MMA) impregnation and polymerization. Bleached birch wood with a preserved hierarchical structure acted as a host for metal ions. Cobalt, nickel, copper, and iron metal salts were used. The location and distribution of metal ions in C-TW as well as the mechanical performance, optical properties, and fire retardancy were investigated. The C-TW coloration is tunable by controlling the metal ion species and concentration. The metal ions reduced heat release rates and limited the production of smoke during forced combustion tests. The potential for scaled-up production was verified by fabricating samples with a dimension of 180 x 100 x 1 (l x b x h) mm(3).

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
Keywords
metal ion, methyl methacrylate (MMA), coloredtransparent wood, fire retardancy, scale-up
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-342301 (URN)10.1021/acsami.3c13585 (DOI)001128280600001 ()38055951 (PubMedID)2-s2.0-85180100479 (Scopus ID)
Note

QC 20240116

Available from: 2024-01-16 Created: 2024-01-16 Last updated: 2024-01-16Bibliographically approved
Hu, Y., Tan, F., Wang, S., Berglund, L., Fan, Y. & Zhou, Q. (2023). Composites of Silk Nanofibrils and Metal-Organic Framework Nanosheets for Fluorescence-Based Sensing and UV Shielding. ACS Applied Nano Materials, 6(7), 6046-6055
Open this publication in new window or tab >>Composites of Silk Nanofibrils and Metal-Organic Framework Nanosheets for Fluorescence-Based Sensing and UV Shielding
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2023 (English)In: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 6, no 7, p. 6046-6055Article in journal (Refereed) Published
Abstract [en]

Silk fibroin, a widely used natural biopolymer, presents remarkable flexibility and biodegradability, making it of great interest as a polymer matrix for functional composite materials. Herein, composites of silk nanofibrils and metal-organic framework (MOF) nanosheets were successfully fabricated by a coincubation and coassembly process. Under heat incubation, silk fibroin self-assembled into one-dimensional nanofibrils, while MOF nanosheets simultaneously covered or wrapped on the silk nanofibrils in a water suspension. Transparent composite membranes were obtained from their water suspensions by the solution casting method. The regenerated silk nanofibrils formed a network structure, and the integrated MOF nanosheets (0.1 to 3.0 wt %) endowed the composites with aggregation-induced emission luminogen (AIEgen)-based fluorescence. The fluorescence intensity of the composites was significantly enhanced owing to the interfacial interactions between silk nanofibrils and MOF nanosheets. The composite membranes also offer excellent UV shielding while maintaining optical transparency in the visible spectrum. This work provides an efficient pathway to fabricate luminescent silk protein-based composites for functional materials such as fluorescence sensing and anticounterfeiting.

Place, publisher, year, edition, pages
American Chemical Society, 2023
Keywords
aggregation-induced emission, composite, metal−organic framework nanosheet, silk nanofibril, UV shielding
National Category
Materials Chemistry Composite Science and Engineering Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-330946 (URN)10.1021/acsanm.3c00386 (DOI)000959898200001 ()2-s2.0-85151354062 (Scopus ID)
Note

QC 20230704

Available from: 2023-07-04 Created: 2023-07-04 Last updated: 2023-07-04Bibliographically approved
Arcieri, N., Chen, B., Berglund, L. & Tavares da Costa, M. V. (2023). Crack growth study of wood and transparent wood-polymer composite laminates by in-situ testing in weak TR-direction. Composites. Part A, Applied science and manufacturing, 173, Article ID 107693.
Open this publication in new window or tab >>Crack growth study of wood and transparent wood-polymer composite laminates by in-situ testing in weak TR-direction
2023 (English)In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 173, article id 107693Article in journal (Refereed) Published
Abstract [en]

TW transparent wood/polymer biocomposite laminates are of interest as multifunctional materials with good longitudinal modulus, tensile strength and optical transmittance. The effect of filling the pore space in wood with a polymer matrix on fracture toughness and crack growth is not well understood. Here, we carried out in-situ fracture tests on neat birch wood and laminates made of four layers of delignified birch veneers impregnated with poly(methyl methacrylate) (PMMA) and investigated crack growth in the tangential-radial (TR) fracture system. Fracture toughness KIc and JIc at crack initiation were estimated, including FEM analysis. SEM microscopy revealed that cracks primarily propagate along the ray cells, but cell wall peeling and separation between the PMMA and wood phases also take place. A combination of in-situ tests and strain field measured by digital image correlation (DIC) showed twice as long fracture process zone of TW laminates compared with neat birch.

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
A. Biocomposites, B. Laminates, C. Fracture, D. Microstructural analysis
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-334342 (URN)10.1016/j.compositesa.2023.107693 (DOI)001054641400001 ()2-s2.0-85165174617 (Scopus ID)
Note

QC 20230821

Available from: 2023-08-21 Created: 2023-08-21 Last updated: 2023-09-11Bibliographically approved
Mavrona, E., Hu, Y., Siqueira, G. D., Ruggeberg, M., Popov, S., Berglund, L., . . . Zolliker, P. (2023). Efficiency assessment of wood and cellulose-based optical elements for terahertz waves. Optical Materials Express, 13(1), 92-103
Open this publication in new window or tab >>Efficiency assessment of wood and cellulose-based optical elements for terahertz waves
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2023 (English)In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 13, no 1, p. 92-103Article in journal (Refereed) Published
Abstract [en]

Polarized THz time domain spectroscopy was used to study the anisotropic properties of wood-based materials for potential optical elements in the THz range, such as half-wave and quarter-wave plates. Wood samples of different species and sample thickness were studied experimentally showing high birefringence but rather high absorption. We elaborate on two approaches to optimize the optical properties for use as wave plates and assess them based on a figure of merit describing their efficiency as a function of birefringence and absorption. The first approach is to dry the wood samples, which significantly improves the efficiency of wave plates. The second approach is the use of artificially produced cellulose samples using 3D printing and freeze drying techniques, which also show birefringence caused by their similar macroscopic cellulose fibre structure. These materials have the potential as cost effective THz elements that are easy to tailor and produce for use at specific frequencies.

Place, publisher, year, edition, pages
Optica Publishing Group, 2023
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-323354 (URN)10.1364/OME.477062 (DOI)000906985800001 ()2-s2.0-85147538219 (Scopus ID)
Note

QC 20230127

Available from: 2023-01-27 Created: 2023-01-27 Last updated: 2023-06-08Bibliographically approved
Tran, V. C., Mastantuoni, G. G., Zabihipour, M., Li, L., Berglund, L., Berggren, M., . . . Engquist, I. (2023). Electrical current modulation in wood electrochemical transistor. Proceedings of the National Academy of Sciences of the United States of America, 120(118), Article ID e2218380120.
Open this publication in new window or tab >>Electrical current modulation in wood electrochemical transistor
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2023 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 120, no 118, article id e2218380120Article in journal (Refereed) Published
Abstract [en]

The nature of mass transport in plants has recently inspired the development of low-cost and sustainable wood-based electronics. Herein, we report a wood electrochemical transistor (WECT) where all three electrodes are fully made of conductive wood (CW). The CW is prepared using a two-step strategy of wood delignification followed by wood amalgamation with a mixed electron-ion conducting polymer, poly(3,4-ethylenedioxythiophene)–polystyrene sulfonate (PEDOT:PSS). The modified wood has an electrical conductivity of up to 69 Sm−1 induced by the formation of PEDOT:PSS microstructures inside the wood 3D scaffold. CW is then used to fabricate the WECT, which is capable of modulating an electrical current in a porous and thick transistor channel (1 mm) with an on/off ratio of 50. The device shows a good response to gate voltage modulation and exhibits dynamic switching properties similar to those of an organic electrochemical transistor. This wood-based device and the proposed working principle demonstrate the possibility to incorporate active electronic functionality into the wood, suggesting different types of bio-based electronic devices.

Place, publisher, year, edition, pages
Proceedings of the National Academy of Sciences, 2023
Keywords
conductivity, electrochemistry, PEDOT:PSS, transistor, wood
National Category
Polymer Chemistry Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-331691 (URN)10.1073/pnas.2218380120 (DOI)001025817800003 ()37094114 (PubMedID)2-s2.0-85153687393 (Scopus ID)
Note

QC 20230713

Available from: 2023-07-13 Created: 2023-07-13 Last updated: 2023-08-15Bibliographically approved
Tavares da Costa, M. V., Li, L. & Berglund, L. (2023). Fracture properties of thin brittle MTM clay coating on ductile HEC polymer substrate. Materials & design, 230, Article ID 111947.
Open this publication in new window or tab >>Fracture properties of thin brittle MTM clay coating on ductile HEC polymer substrate
2023 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 230, article id 111947Article in journal (Refereed) Published
Abstract [en]

Thin clay coatings can be deposited from water dispersions for the purpose of improved gas barrier properties and fire retardancy of polymeric materials. Mechanical properties of the coatings are difficult to assess, since they are very thin (≈1µm). In-situ tests using a micro tensile stage in a scanning electron microscope reveal a thickness-dependent microcracking mechanism, and Weibull parameters for coating fracture are extracted. Complex fracture events are identified, related to a weak clay coating-polymer substrate interface. A micromechanical finite element formulation provides values of 5 MPa for interfacial shear strength and 1 J/m2 for interfacial fracture toughness. From the multiple cracking behavior of the clay coating, a clay strength ≈ 225 MPa is estimated by the Weibull strength parameter from fragmentation diagrams. The method may be extended to other combinations of brittle coating-ductile substrates.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Debonding, Fragmentation test, In-situ test, Interface, Microcracking, MTM tensile strength
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-331602 (URN)10.1016/j.matdes.2023.111947 (DOI)001041789400001 ()2-s2.0-85154068691 (Scopus ID)
Note

QC 20230711

Available from: 2023-07-11 Created: 2023-07-11 Last updated: 2023-08-18Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-5818-2378

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