| 11. |
- Härdelin, Linda, 1977, et al.
(author)
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Hemicellulose foam
- 2014
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In: Proc Materials for Tomorrow. ; , s. Nr 24-
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Conference paper (other academic/artistic)
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| 12. |
- Köhnke, Tobias, 1978, et al.
(author)
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Kraft pulp hornification: A closer look at the preventive effect gained by glucuronoxylan adsorption
- 2010
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In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617. ; 81:2, s. 226-233
-
Journal article (peer-reviewed)abstract
- Xylan is known to adsorb irreversibly on cellulose and on bleached kraft pulp fibres. This investigation shows that adsorption of birch glucuronoxylan (GX) reduces the degree of drying-induced property changes of bleached softwood kraft pulp fibres. GX was adsorbed at different amounts on never-dried fibres, which provided pulps with xylan contents ranging from 67 to 126 mg/g. By fluorescent labelling of the GX, followed by adsorption and subsequent imaging using confocal laser scanning microscopy, it was concluded that GX adsorbs on fibril surfaces throughout the fibre wall with enrichment on the outer fibre surface. Adsorption of GX before drying preserved a considerable part of the fibre-swelling (water retention value and fibre saturation point), specific fibre surface area, and wet fibre flexibility observed in the never-dried state. It is therefore suggested that GX adsorption reduces the degree of drying-induced fibre wall cross-linking. The use of GX as a hornification inhibitor would provide once-dried pulps with increased tensile strength and beatability.
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| 13. |
- Lund, Kristoffer, 1983, et al.
(author)
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Diepoxide treatment of softwood kraft pulp: influence on absorption properties of fibre networks
- 2011
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In: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 18:5, s. 1365-1375
-
Journal article (peer-reviewed)abstract
- Many different approaches to the introduction of intra-fibre cross-links in fibres for use in absorption products are described in the patent literature, but relatively little has been done in terms of academic research. In this study, the long fibre fraction of a Scandinavian softwood kraft pulp has been cross-linked with the diepoxide 1,4-butanediol diglycidyl ether (BDDE). The fibre properties and the performance of the pulp in low density fibre networks were analyzed. In experiments, the cross-linking agent (BDDE) was dissolved in acetone and then mixed with the pulp. It was shown that a prior wash with NaOH (0.1 M) activates the polysaccharides and increases the extent of cross-linking, detected as a decrease in the water retention value. Chemical analysis of modified fibres also gave a clear indication of that cross-linking reactions actually occurred. The pulp properties could furthermore be influenced by varying time, temperature and the amount of BDDE in the reaction. It was also shown that it is possible to use water as a solvent for the cross-linking agent, even though the reactivity of water towards diepoxide must be considered to be high. The cross-linked pulps showed wet bulk under load comparable to that of the mechanical pulps and enhanced properties than unmodified Scandinavian softwood kraft pulp. It was also observed that fibre network test pads of the cross-linked pulp fibres, after being tested in the wet state, regained a substantially large part of their low-density structure when air-dried.
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| 14. |
- Makhubela, B. C. E., et al.
(author)
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Hydroformylation of 1-octene using low-generation Rh(I) metallodendritic catalysts based on a tris-2-(2-pyridyliminoethyl)amine scaffold
- 2012
-
In: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 41:35, s. 10715-10723
-
Journal article (peer-reviewed)abstract
- The synthesis and characterization of low-generation pyridylimine Rh(I) metallodendrimers is described. These metallodendrimers were obtained via a Schiff base condensation of tris-2-(aminoethyl) amine with 2-pyridinecarboxaldehyde to afford the tris-2-(2-pyridylimine ethyl) amine ligand (1). Subsequent complexation reactions with [RhCl(CO)(2)](2) and [RhCl(COD)](2) yielded the corresponding metal-containing dendrimers containing RhCl(CO) and Rh(COD) moieties on the periphery. These new rhodium metallodendrimers (2 and 3) and their precursor ligand (1) are thermally stable and have been characterized using H-1 NMR, C-13 NMR, P-31 NMR, FT-IR spectroscopy, elemental analysis as well as mass spectrometry. The Rh(I) metallodendrimers are highly active and chemo- and regioselective in the hydroformylation of 1-octene. Aldehydes were favoured at moderate to high temperatures (95 degrees C and 75 degrees C) and pressure (30 bars), while more iso-octenes were formed at low temperature (55 degrees C) and pressures (5 and 10 bars). The mononuclear analogues (5 and 6) also produced more aldehydes (albeit showing catalyst decomposition at 95 degrees C and 75 degrees C, 30 bars) and these aldehydes were mostly branched.
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| 15. |
- Mungwe, N., et al.
(author)
-
Cationic palladacycles as catalyst precursors for phenyl acetylene polymerization
- 2011
-
In: Journal of Organometallic Chemistry. - : Elsevier BV. - 0022-328X. ; 696:22, s. 3527-3535
-
Journal article (peer-reviewed)abstract
- Novel cationic palladacycles based on benzylidene-2,6-diisopropylphenylimines were prepared via C-H activation using Pd(CH(3)CN)(2)Cl(2) as metal precursor. The complexes were fully characterized by IR and NMR spectroscopy, mass spectrometry and elemental analysis. The cationic palladacycles were found to be active catalysts for the polymerization of phenylacetylene producing largely trans-cisoidal PPA.
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