Isolation and chemical modification of arabinoxylan and galactoglucomannan
Today’s society is based on the use of fossil fuels, where oil is used as transportation fuel and as raw material in the petrochemical industry. Efforts are made to increase the use of bio-based materials, since oil is a non-renewable source and a greenhouse gas contributor.
The raw materials used in this thesis are agricultural and forestry by-products. Alkaline extraction was used to isolate the hemicellulose arabinoxylan (AX) from barley husk, while the hemicellulose galactoglucomannan (GGM) was obtained through concentration of pulp process water. Hemicelluloses can be used to produce materials. One way to increase the processability of the hemicellulose is to perform chemical modifications on it. By doing so, the properties of hemicellulose can be altered, such as decreased glass transition temperature (Tg), which will change the ability to process the hemicellulose into material.
Two chemical modifications are described in this work; PEGylation of AX and etherification with butyl glycidyl ether (BGE) on GGM. PEG was successfully coupled to AX, acting as an internal plasticiser, resulting in a decreased Tg. The degree of molar substitution of BGE on GGM affected the thermal and mechanical properties of the modified raw materials. The modified raw materials were investigated for the production of new materials with altered properties compared to the starting materials.