Hemicelluloses may become readily available if the production of dissolving pulp increases significantly, eg. in case of wood-based fibres to replace e.g. synthetic textile and cotton fibres. Modification methods for the abundant natural polymers cellulose and xylan have been developed after pulp extraction and concentration of xylan. In projects by VTT etherifications and esterifications of the polysaccharides were performed using among other propylene oxide and analogues as well as acetic anhydride and analogues.
Xylan hemicellulose was found to be a good starting material for modification of potential polymers in film, coating and barrier applications. In these applications the modified xylans provided many advantageous properties. Modified hydroxypropyl xylan provided strong transparent films. Dispersions of the modified xylan provided also good surface strength that could be demonstrated in the pigment coating applications of paper. The fatty acid derivatives of the hemicellulose provided good grease and water vapour barrier.
Tags: Xylan hemicellulose, hydroxypropyl xylan, polysaccharides
Source: ForestTech, 2012-04-30.