/ Research / Fundamental Res... / FT 2 - Dissolution
Fundamental Theme 2 - Disassembly of polymers. Extraction, dissolution behaviour, and solution properties of polymeric components
Theme leader: Anna Suurnäkki (VTT Technical Research Centre of Finland, Finland)
Abstract:
The theme aims at developing novel methods and techniques based on structure-preserving solvents for extraction and dissolution of polymeric polysaccharide components from biomass, as well as at characterizing the behaviour of polymers in these systems in detail. Various pre-treatment techniques, including enzymatic, physical and chemical treatments will be used to enhance the disassembly of polysaccharides. The use of novel systems to modify the structural properties of cellulose or hemicelluloses by selected reorganization, swelling or dissolution could permit access to new materials. For such purposes the scientific basis has to be set up to understand the interaction between solvents and the polysaccharide structure.
The research is expected to foster ideas for new technology that could enhance and intensify the extraction of polysaccharides from various, chosen biomass materials. It is also expected to open doors to entirely new techniques for comprehensive utilization of biomass for high-value products and materials.
Objectives:
a) Understanding the key factors restraining the disassembly of polysaccharides from various biomass materials
b) Identification and evaluation of novel alternative extraction and fractionation systems for polysaccharides
c) Evaluation of preteatment (enzymatic, physical, chemical) methods for improved fractionation
d) Novel product concepts based on fractionation methods
State of the art:
Fractionation of biomass with new structure-preserving methods would allow isolation and characterization of various polysaccharides in an intact form. Preservation of structure would also enable flexibility in further controlled modification of polysaccharides. Current methods usually lead to depolymerization and/or removal of side groups. Presently, new biotechnical and green chemistry methods are emerging, and are expected to be industrially applicable within a scale of 5 to 10 years. It can also be expected that these novel methodologies will be further developed leading to novel products and applications.
In order to develop new technologies for structure-preserving extraction of the main biomass components, new deeper knowledge is needed on the chemistry and morphology of different biomass tissues and components. The scientific target of the theme is to achieve understanding of the restraints for dissolution and extraction of biomass polysaccharides, and at finding means of overcoming these restraints with new pre-treatment methods and extraction techniques, using both conventional and novel speciality solvents.
References:
1) Ragauskas A, Williams CK, Davison BH, Britovsek G, Cairney J, Eckert CA, Frederic WJ; Hallett, JP, Leak DJ, Liotta CL, Mielenz JR, Murphy R, Templer R, Tschaplinski T. (2006). The path forward for biofuels and biomaterials, Science, 311, 484-489.
2) Pere J, Siika-aho M, Viikari L. (2000). Biomechanical pulping with enzymes: Response of coarse mechanical pulp to enzymatic modification and secondary refining. Tappi J. 83(5), 8 p.
3) Wyman CE, Decker SR, Himmel ME, Brady JW, Skopec CE, Viikari L. (2004). Hydrolysis of cellulose and hemicellulose. In: Polysaccharides: Structural Diversity and Functional Versatility. 2nd ed. Dumitriu S. (Ed.). New York: Marcel Dekker, Inc., 995-1033.
4) örså F, Holmbom B, Thornton J. (1997). Dissolution and dispersion of spruce wood components into hot water. - Wood Sci. Technol. 31 (1997) 279-290.
5) Willför S, Sjöholm R, Laine C, Holmbom B (2002). Structural features of water-soluble arabinogalactans from Norway spruce and Scots pine heartwood. - Wood Sci. Technol. 36 (2002) 101-110.
6) Willför S, Sjöholm R, Laine C, Roslund M, Hemming J, Holmbom B. (2003), Characterisation of water-soluble galactoglucomannans from Norway spruce wood and thermomechanical pulp, Carbohydr. Polym. 52:2, 175-187
7) Willför, S., Rehn, P., Sundberg, A., Sundberg, K. and Holmbom, B. (2003), Recovery of water-soluble acetyl-galactoglucomannans from mechanical pulp of spruce, Tappi J. 2:11, 27-32
8) Okubayashi S., Bechtold T. (2005) Alkali uptake and swelling behaviour of lyocell fiber and their effects on crosslinking reaction, Cellulose, 12/5, 459-467.
9) W. Zhang, S. Okubayashi, Badura W., T. Bechtold (2006), Fibrillation Tenency of celllosic fibers Part 7. Combined effects of treatments with an alkali, crosslinking agent and reactive dye, Journal of Applied Polymer Science, 100/2, 1176-1183
10) C. Ibanescu, C. Schimper, T. Bechtold (2005), Alkaline Treatment of Cotton in Different Reagent Mixtures with Reduced Water Content. I. Influence of alkali type and additives, Journal of Applied Polymer Science, 99/5, 2848-2855
Programme of the work:
a) Pretreatments for enhanced fractionation /dissolution
Investigation of dissolution and fractionation of polysaccharides from various raw materials (softwood, hardwood, agricultural fibres, pulps) by using various pre-treatment methods (enzymes, physical and chemical methods) for specific cleavage or for removing impurities in extracted products.
b) Fractionation mechanisms of polymers in various solvents
Dissolution of polysaccharides by using solvents for specific cleavage, by using extraction intensification, by understanding solvent properties and by tracing or removing impurities in extracted products.
c) Characteristics and dissolution behaviour of polymeric components
Understanding on the supramolecular structure of polysaccharides in chosen solvents and characterization the mechanism of dissolution and polymer and solvent interactions by analytical and modelling methods.