Description succincte
(Anglais)
|
The two main objectives of the project are 1) production and complete characterisation of fractionated lignin that can be used as reference material by the international scientific community for calibration and other verification purposes 2) further improvement of the molecular mass determination of lignin by improving calibration and operation conditions of the method. Furthermore, the analytical cluster of the first step of the project will be completed with the data of the fractionated lignins and the dissemination of the corresponding analytical methods will be continued at national and international level.
|
Partenaires et organisations internationales
(Anglais)
|
AT, CH, DE, DK, ES, FI, FR, HR, HU, IT, LV, NL, NO, PT, RO, SE, SI, UK
|
Résumé des résultats (Abstract)
(Anglais)
|
The membrane fractionation of lignin in alkaline solution was developped at laboratory and pilot scale. At laboratory scale, parameters like concentration, pH, temperature and membrane type have been tested. At pilot scale, a 5kg lignin powder sample was separated into 4 fractions, each fraction weighing between 0.5g and 1.5kg. Recovery of the solid lignin in all the fractions was optimised with regard to filtration time, acid consumption and purity of the end product. A powder of high purity could be obtained for all lignins. The achieved results have a direct application in future lignin production plants. The obtained data shows that the quality of lignin can be significantly improved by using membrane technology. The samples were analysed by HPSEC, NMR, MALDI-TOF, FTIR, UV-VIS, CHNS-Analyser. Among the measured properties were functional groups (aromatic and aliphatic OH, carboxyl, methoxyl), solubility (ethanol, furfuryl alcohol, THF) and purity (ash, lignin, carbohydrate content). Special efforts were given to the optimisation of the molecular size determination. The resulting best optimised method is based on DMF and PMMA calibration. Alkaline chromatography showed as well promising results. Chemical modifications (acetylation, bromo-acetylation, ion pairing) did not give satisfactory results. Four standard fractions of the analysed lignins have been made available for calibration and referencing purposes, namely for the molecular size determination. Analytical tools were developped as well for application oriented parameters: Zetapotential, particle distribution in dispersions, reactivity in phenolic resins and melting behaviour. The results showed that membrane fractionation allows to obtain a very good dispersion of properties among the fractions and this with regard to all analysed parameters. Solvent and pH fractionation were also tested and showed as well promising results comparable to the ones achieved by membranes.
|
