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| 3. |
- Fu, Qiliang, 1986-, et al.
(författare)
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Honeycomb like templates prepared from balsa wood
- 2015
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Ingår i: 20th International Conference on Composite Materials, ICCM 2015. - : International Committee on Composite Materials.
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Konferensbidrag (refereegranskat)abstract
- In the current study, we have used sodium chlorite and sodium hydroxide as extraction solutions, to remove lignin and hemicelluloses from the Balsa (Ochroma Lagopus) wood tissues, without damaging the wood honeycomb architecture. Surface morphologies are studied using scanning electron microscopy (SEM). In addition, sugars analysis of the chemically extracted wood is reported.
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| 4. |
- Fu, Qiliang, et al.
(författare)
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Nanostructured Wood Hybrids for Fire-Retardancy Prepared by Clay Impregnation into the Cell Wall
- 2017
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 9:41, s. 36154-36163
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Tidskriftsartikel (refereegranskat)abstract
- Eco-friendly materials need "green" fire-retardancy treatments, which offer opportunity for new wood nanotechnologies. Balsa wood (Ochroma pyramidale) was delignified to form a hierarchically structured and nanoporous scaffold mainly composed of cellulose nanofibrils. This nanocellulosic wood scaffold was impregnated with colloidal montmorillonite clay to form a nanostructured wood hybrid with high flame-retardancy. The nanoporous scaffold was characterized by scanning electron microscopy and gas adsorption. Flame-retardancy was evaluated by cone calorimetry, whereas thermal and thermo-oxidative stabilities were assessed by thermogravimetry. The location of well-distributed clay nanoplatelets inside the cell walls was confirmed by energy-dispersive X-ray analysis. This unique nanostructure dramatically increased the thermal stability because of thermal insulation, oxygen depletion, and catalytic charring effects. A coherent organic/inorganic charred residue was formed during combustion, leading to a strongly reduced heat release rate peak and reduced smoke generation.
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| 5. |
- Fu, Qiliang, 1986-
(författare)
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Transparent plywood
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Fu, Qiliang, 1986-, et al.
(författare)
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Transparent plywood as a load-bearing and luminescent biocomposite
- 2018
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Ingår i: Composites Science And Technology. - : Elsevier. - 0266-3538 .- 1879-1050. ; 164, s. 296-303
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Tidskriftsartikel (refereegranskat)abstract
- Transparent wood (TW) structures in research studies were either thin and highly anisotropic or thick and isotropic but weak. Here, transparent plywood (TPW) laminates are investigated as load-bearing biocomposites with tunable mechanical and optical performances. Structure-property relationships are analyzed. The plies of TPW were laminated with controlled fiber directions and predetermined stacking sequence in order to control the directional dependence of modulus and strength, which would give improved properties in the weakest direction. Also, the angular dependent light scattering intensities were investigated and showed more uniform distribution. Luminescent TPW was prepared by incorporation of quantum dots (QDs) for potential lighting applications. TPW can be designed for large-scale use where multiaxial load-bearing performance is combined with new optical functionalities.
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| 7. |
- Fu, Qiliang, 1986-
(författare)
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Wood Nanotechnologies for Transparency, Fire Retardancy and Liquid Separation
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, wood nanotechnologies for transparent, fire-retardant and hydrophobic/lipophilic wood have been developed. There are two main parts; wood template preparation/processing concepts and materials design using these templates.In the wood template processing part, highly porous nanostructured wood templates are prepared. Relationships between processes and material structures are studied. Three chemical treatment methods are used. Lignin and/or chromophores are removed from cell wall, so that nanoscale pores are formed in the cell wall. For preparation of transparent wood, a lignin-retaining method improves physical properties of the template. The pore structures are characterized by scanning electron microscopy and gas adsorption measurement of specific surface area. The compositions of the templates are characterized. Compared with native wood, these templates have nanoscale porosity which provides opportunity for new types of wood modification.In the materials design part, wood nanotechnologies are used for transparent wood as well as for hydrophobic/lipophilic and fire-retardant wood. Two main strategies are used: i) nanoparticles are embedded inside the cell wall; ii) polymers are impregnated in lumen space, and sometimes also inside the cell wall. The transparent wood is prepared by MMA monomer/oligomer impregnation of lumen space. MMA has similar refractive index to the delignified template, so that scattering is reduced and transparent wood with favorable optical and mechanical properties is obtained. The structure and functional properties are studied. Laminated transparent plywood is designed to modify mechanical properties. Transparent wood and transparent plywood are demonstrated in applications combining loading-bearing properties with optical performance such as luminescent properties.The highly porous wood template cell walls are also impregnated with colloidal montmorillonite clay or epoxy/amine solutions to modify the cell wall and form nanostructured biocomposites. The structure and properties of the two materials are investigated; wood/clay hybrids for flame-retardancy and wood/epoxy biocomposites for oil/water separation.
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| 8. |
- Fu, Qiliang, 1986-
(författare)
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Wood Nanotechnology for Strong, Mesoporous, and Hydrophobic Biocomposites for Selective Separation of Oil/Water Mixtures
- 2018
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Tremendous efforts have been dedicated to developing effective and eco-friendly approaches for separation of oil–water mixtures. Challenges remain in terms of complex processing, high material cost, low efficiency, and scale-up problems. Inspired by the tubular porosity and hierarchical organization of wood, a strong, mesoporous, and hydrophobic three-dimensional wood structure is created for selective oil/water separation. A delignified wood template with hydrophilic characteristics is obtained by removal of lignin. The delignified wood template is further functionalized by a reactive epoxy–amine system. This wood/epoxy biocomposite reveals hydrophobic/oleophilic functionality and shows oil absorption as high as 15 g/g. The wood/epoxy biocomposite has a compression yield strength and modulus up to 18 and 263 MPa, respectively, at a solid volume fraction of only 12%. This is more than 20 times that of cellulose-based foams/aerogels reconstructed from cellulose nanofibrils. The favorable performance is ascribed to the natural hierarchical honeycomb structure of wood. Oil can be selectively absorbed not only from below but also from above the water surface. High oil/water absorption capacity of both types of wood structures (delignified template and polymer-modified biocomposite) allows for applications in oil/water separation.
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| 9. |
- Hajian, Alireza, 1986-, et al.
(författare)
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Recyclable and superelastic aerogels based on carbon nanotubes and carboxymethyl cellulose
- 2018
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Ingår i: Composites Science And Technology. - : Elsevier. - 0266-3538 .- 1879-1050. ; 159, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Deformation mechanisms are largely unknown for superelastic carbon nanotube (CNT) aerogels, and this hampers materials design efforts. The CNT network in the cell walls is typically crosslinked or connected by a thermoset polymer phase. In order to create a recyclable superelastic aerogel, unmodified single or multi-walled CNTs were dispersed in water by adding to aqueous carboxymethyl cellulose (CMC) solution. Directional freeze-drying was used to form honeycombs with cell walls of random-in-the-plane CNTs in CMC matrix. Cell wall morphology and porosity were studied and related to CNT type and content, as well as elastic or plastic buckling of the cell walls under deformation. CMC acts as a physical crosslinker for the CNTs in a porous cell wall. Aerogel structure and properties were characterized before and after recycling. The conductivity of the composite aerogel with a density of 10 kg/m3, 99% porosity and 50 wt % single-walled CNT exceeds 0.5 S/cm. The potential of these superelastic and conductive aerogels for applications such as mechanoresponsive materials was examined in cyclic conductivity tests at different strains. This opens a new route for recyclable superelastic CNT composite aerogels, avoiding material loss, chemical treatment or addition of other components.
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| 10. |
- Li, Yuanyuan, et al.
(författare)
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Lignin-Retaining Transparent Wood
- 2017
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Ingår i: ChemSusChem. - : WILEY-V C H VERLAG GMBH. - 1864-5631 .- 1864-564X. ; 10:17, s. 3445-3451
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Tidskriftsartikel (refereegranskat)abstract
- Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30wt% of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80wt% of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83%, haze of 75%, thermal conductivity of 0.23WmK(-1), and work-tofracture of 1.2MJm(-3) (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings.
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