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| 2. |
- Hedmark, Per G., et al.
(författare)
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Selective etching of thermotropic liquid crystalline polyesters
- 1987
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 34:2, s. 743-762
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Tidskriftsartikel (refereegranskat)abstract
- DSC, IR, ESCA, macroscopic etching rate measurements, analysis of etchant solution, and electron microscopy conclusively show that n-alkylamines (ethylamine, n-propylamine, n-butylamine, and n-pentylamine) and NaOH selectively degrade (etch) the ethylene terephthalate (ET)-rich phase in glassy liquid crystalline poly(p-hydroxybenzoic acid-co-ethylene terephthalate) [P(HBA-ET)] with molar compositions 0.60:0.40 and 0.80:0.20. ESCA demonstrates the excellent selectivity of the n-alkylamine etchants in the 0.60:0.40 copolymer. The 50 Å top layer of the etched samples contains 95 mol% HBA. Treatment with H2SO4 and NH3 gives ambiguous results, and these compounds are not suitable as etchants. It is demonstrated by electron microscopy on the 0.60:0.40 copolymer, in accordance with earlier reports by Joseph et al.,5-8 that the ET-rich phase is discontinuous (1-2 m spheres) and surrounded by an HBA-rich matrix. SEM is a useful tool for characterization of this morphology. However, both phases have a substracture which is revealed only by TEM. The morphology of the 0.80:0.20 copolymer is fine-textured, which means that SEM is a less suitable method for the characterization of etched samples.
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| 3. |
- Jönsson, L., et al.
(författare)
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Trametes versicolor ligninase: isozyme sequence homology and substrate specificity
- 1989
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Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 247:1, s. 143-146
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Tidskriftsartikel (refereegranskat)abstract
- The substrate specificity of three ligninase isozymes from the white-rot fungus Trametes versicolor has been investigated using stereochemically defined synthetic dimeric models for lignin. The isozymes have been found to attack non-phenolic β-O-4 as well as β-1 lignin model compounds. This finding confirms the classification of the isozymes from T. versicolor as ligninases. The amino-terminal residues of the three isozymes from T. versicolor have been determined using Edman degradation. Minor differences found between the sequences suggest the existence of several structural genes for ligninase in T. versicolor. Comparisons have been made with the sequences of three previously reported ligninases from Phanerochaete chrysosporium, another lignin-degrading fungus. One of the sequences from P. chrysosporium is distinctly more similar to the T. versicolor isozymes than to the other two sequences from P. chrysosporium.
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| 5. |
- Morén, Tom
(författare)
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Conditioning of Pine during artificial drying in a kiln
- 1987
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Ingår i: Proceedings of the International Conference on Stress Development and Degrade During Wood Drying, Skellefteå, Sweden, September 28-October 2, 1987. - Skellefteå : Luleå University of Technology.
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Konferensbidrag (refereegranskat)
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