Modification and characterization of wood components

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Title: Modification and characterization of wood components
Author: Kakko, Tia-Annette
Contributor organization: University of Helsinki, Faculty of Science
Doctoral Programme in Chemistry and Molecular Research
Helsingin yliopisto, matemaattis-luonnontieteellinen tiedekunta
Kemian ja molekyylitutkimuksen tohtoriohjelma
Helsingfors universitet, matematisk-naturvetenskapliga fakulteten
Doktorandprogrammet i kemi och molekylära vetenskaper
Publisher: Helsingin yliopisto
Date: 2019-02-01
Language: eng
Thesis level: Doctoral dissertation (article-based)
Abstract: The separated wood components cellulose, hemicelluloses, and lignin allow for the production of various materials via chemical modifications. In addition to modifications, understanding the structural features of these products is important for enabling tailored processes for commodities. In this thesis, the introduction covers background information concerning cellulose chemistry. The dissolution of cellulose in various solvent systems is compared, and the usability of these solvents in acetylation of polysaccharides is assessed. Typically, the solvents used in Viscose or Lyocell processes are not suitable for chemical modifications, mainly due to their reactivity with either cellulose hydroxyls or used reagents. Furthermore, in current industrial cellulose acetate (CA) processes, the degree of polymerization (DP) of the product decreases. The results and discussion present the possibility of using ionic liquids as a reaction media for homogeneous acetylation of hemicelluloses and cellulose. The aim is to produce new methods in ionic liquids, in which tunable substitution is possible for acetylated hemicelluloses and CAs without substantial losses in DP. Furthermore, the procedure is upscaled and acetate fibers are produced with good spinnability and fiber characteristics in collaboration with Aalto University. Another issue under study is lignin chemistry, especially the structural characterization of hydrothermally (HT) treated Kraft lignin. The results demonstrate that diphenyl methanes are formed during HT treatment of Kraft lignin.
Subject: Kemia
Rights: Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.

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