| 1. |
- Horvath, Andrew T., et al.
(författare)
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Effect of Cross-Linking Fiber Joints on the Tensile and Fracture Behavior of Paper
- 2010
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 49:14, s. 6422-6431
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Tidskriftsartikel (refereegranskat)abstract
- The tensile and fracture properties of cross-linked paper were investigated at low and high relative humidity by cross-linking the joints formed between fibers. Cationic acetal dextran served as a model cross-linking agent, as it can be prepared to adsorb specifically to the fiber surface. Thus, cross-linking occurs only in the joints between fibers. The kinetics of hydrolysis was investigated to optimize the stock preparation, such that the resulting aldehyde groups react as the paper is dried. The effect of the cross-link density on the tensile and fracture properties was studied by varying the amount of acetal groups adsorbed to the pulp fibers. At low humidity, cross-linking improved the tensile and fracture properties of paper, although lower cross-link densities yielded better properties. Cross-linking was not effective at high relative humidty, as the tensile strength and stiffness were not improved. However, the fracture properties were significantly improved.
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| 2. |
- Hu, Liangbing, et al.
(författare)
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Transparent and conductive paper from nanocellulose fibers
- 2013
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Ingår i: Energy & Environmental Science. - 1754-5692 .- 1754-5706. ; 6:2, s. 513-518
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Tidskriftsartikel (refereegranskat)abstract
- Here we report on a novel substrate, nanopaper, made of cellulose nanofibrils, an earth abundant material. Compared with regular paper substrates, nanopaper shows superior optical properties. We have carried out the first study on the optical properties of nanopaper substrates. Since the size of the nanofibrils is much less than the wavelength of visible light, nanopaper is highly transparent with large light scattering in the forward direction. Successful depositions of transparent and conductive materials including tin-doped indium oxide, carbon nanotubes and silver nanowires have been achieved on nanopaper substrates, opening up a wide range of applications in optoelectronics such as displays, touch screens and interactive paper. We have also successfully demonstrated an organic solar cell on the novel substrate.
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| 3. |
- Lindström, Stefan B, et al.
(författare)
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Thermally activated capillary intrusion of water into cellulose fiber-based materials
- 2011
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Ingår i: The proceedings of the Fundamental and Applied Pulp & Paper Modelling Symposium 2011. - : PAPTAC. - 9782980832376 ; , s. 13-26, s. 13-26
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Bokkapitel (refereegranskat)abstract
- The imbibition of water into cellulose fiber-based materials is studied with focus on the regime dominated by contact line dynamics rather than hydrodynamic drag of the bulk porous structure. Capillary rise is studied under the influence of gravity for different paper grades with a wide range of porosities. It is found that the capillary rise is logarithmic in time in the limit of long time-scales. This behavior is in excellent agreement with the Molecular Kinetics Theory (MKT) for contact line dynamics. For high-porosity paper grades, this previously neglected logarithmic regime starts already at about $5$\,cm of capillary intrusion, underscoring the critical importance of the contact line dynamics to the performance of cellulosic absorbents.
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| 4. |
- Rosén, Arne, et al.
(författare)
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Experimental and theoretical analysis of carbon nanotubes grown from catalytic nanoparticles of defined size distribution
- 2012
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Konferensbidrag (refereegranskat)abstract
- We report use of a dip-coating method to prepare catalyst particles (mixture of iron and cobalt) with a controlled diameter distribution on silicon wafer substrates by changing the solution concentration and withdrawal velocity. The size and distribution of the prepared catalyst particles were analyzed by atomic force microscopy. Carbon nanotubes were grown by chemical vapor deposition, CVD, on the substrates with the prepared catalyst particles. By decreasing the particle size, the growth of carbon nanotubes can be tuned from few walled carbon nanotubes, with homogeneous diameters, to highly pure single walled carbon nanotubes, SWNT. Analysis of the Raman radial breathing mode, showed a relatively broad diameter distribution (0.8-1.4 nm) of single walled carbon nanotubes, SWNT, with different chiralities. By changing the size and composition of the catalyst particles but maintain the growth parameters, the chiralities of SWNT were reduced to mainly four different types: (12,1), (12.0), (8,5) and (7,5) of which quantity is 70 % of all the nanotubes.
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