Development of a method for the production of hemicellulosic gels from Sitka spruce

Timber can be used as a sustainable source for process chemicals (Silvichemicals), with particular emphasis being placed on wood as source of chemical feedstocks. Bulk Silvichemicals are unlikely to be cost competitive with fossil fuel derived chemicals at present so ideally, research should be directed towards materials with exploitable properties and high intrinsic value in the market place. Research has generally been aimed at the utilisation of cellulose, extractives or degradation products with only minor interest in the utilisation of undegraded hemicelluloses. To increase the intrinsic value the environmental credentials of the product must be considered. The aim of this study was to development a mechanical and/or mild chemical method for the extraction of hemicelluloses in the form of gels. A number of parameters were tested and are detailed and discussed in terms of effectiveness and feasibility. Mechanical refining followed by mild alkaline extraction was found to be effective on a laboratory scale.