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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Kalliola, Anna
VTT Technical Research Centre of Finland
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (6/6 displayed)
- 2022LigniOx Lignins - Sustainable Depressants for Froth Flotation in Mineral Processing
- 2022LigniOx Lignins as Sustainable Bio-Based Dispersants
- 2022Valorization of Industrial Spruce Bark by Alkaline Extraction
- 2015Chemical and enzymatic oxidation using molecular oxygen as a means to valorize technical lignins for material applications
- 2014Experiences of kraft lignin functionalization by enzymatic and chemical oxidationcitations
- 2013Cellulase-lignin interactionscitations
Places of action
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article
Experiences of kraft lignin functionalization by enzymatic and chemical oxidation
Abstract
Linear hydrophilic derivatives are expected to softenlignin and improve its utilization in compositeapplications. Oxidation by means of laccase in thepresence of oxygen was employed in an attempt tofunctionalize commercial kraft lignin by vanillicacid-PEG ester and ether derivatives. Thielavia arenariaand Melanocarpus albomyces laccases at pH 6 and 8 wereused. According to O2 consumption and the increase inmolar mass, the tested laccases were active toward thelignin and the vanillic acid derivatives and also formedcorresponding phenoxyl radicals. However, homogenouspolymerization instead of cross-coupling andfunctionalization took place. As an alternative, ligninfunctionalization by the ester derivative by chemicaloxidation under alkali-O2 conditions was also tested.Efficient lignin polymerization was observed. However,functionalization was not detected. Interestingly, aclear decrease in lignin glass transition temperature wasobtained by an isolation procedure that includedfreeze-drying. This suggests that functionalization maynot be necessary to induce the desired softening effect.