Comparison of the surface activity of hemicelluloses extracted from spruce and birch sawdust

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Journal Title
Journal ISSN
Volume Title
Kemian tekniikan korkeakoulu | Master's thesis
Date
2018-12-11
Department
Major/Subject
Fibre and Polymer Engineering
Mcode
CHEM3024
Degree programme
Master's Programme in Chemical, Biochemical and Materials Engineering
Language
en
Pages
92
Series
Abstract
This thesis investigated the surface activity of four extracted, unmodified hemicelluloses, namely, galactoglucomannan, GGM, phenolic galactoglucomannan, pGGM, glucuronoxylan, GX, and phenolic glucuronoxylan, pGX. It was determined that the relative amount of sugars was almost the same for GGM and pGGM as well as GX and pGX. With the increased concentration, the lowest surface tension was determined for pGX while the highest foamability and foam stability was observed for GX. The acetylation degree and the presence of residual lignin greatly affected the foam properties. The bubble size (optical microscopy) increased over time at increased concentration, owing to the combination of different foam destabilisation mechanisms. Hemicellulose aggregation was investigated via dynamic light scattering. In contrast to the aggregates formed by GGM and GX, which remained stable as the concentration was increased, those from pGGM and pGX became smaller. This is likely due to the presence of free and bound lignin. Overall, the better foamability and foam stability over time for GX suggest this extracted hemicellulose as an alternative to synthetic amphiphilic molecules.
Description
Supervisor
Rojas, Orlando
Thesis advisor
Xiang, Wenchao
Keywords
hemicelluloses, foams, acetyl groups, lignin
Other note
Citation