Modification and Utilization of Wood Hydrolysates

Abstract: Polysaccharides have been used for many years in a variety of products such as food, fuel supply and industrial products. During recent years there has been an increasing interest in a group of polysaccharides, hemicelluloses, due to their highly availability, renewability and potentially low price. It is however a complicated process to extract highly purified hemicellulose and a more practical process is required so that a less refined resource can be used.This thesis presents a study of the utilization of a simply filtrated and upgraded renewable biomass from the forest industry, so called wood hydrolysate. The wood hydrolysate is rich in hemicelluloses and contains some lignin.Microspheres were successfully produced in a benign way from four different hydrolysates; two from softwood and two from hardwood. The microspheres were prepared in a water-in-oil emulsion and different parameters were regulated. The concentration of the dispersed phase, the temperature and the volume ratio of the dispersed phase and the continuous phase were changed and screened in a multi-variate statistical analysis program.A series of hydrogels based on renewable wood hydrolysate were modified and their ability to swell was assessed. An unsaturated alcohol was activated with N,N’-carbonyldiimidazole (CDI), coupled to the hydroxyl group on the hemicellulose backbone and then radically crosslinked with acrylic acid as co-monomer to form a network. Two of the four wood hydrolysates were modified, one from softwood and one from hardwood, as well as the pure hemicelluloses. Hydrogels was successfully produced with the wood hydrolysate from hardwood and pure hemicellulose and the gels from the modified wood hydrolysate swelled the most, almost 30 % of its own weight.In conclusion, this thesis shows that it is possible to use the renewable biomass, wood hydrolysate, in a variety of forms for future applications.