Lignin and Hemicellulose in Dispersions - as Surfactants and Functional Materials
Borenius, Patrik (2019)
2019
Teknis-luonnontieteellinen DI-ohjelma - Degree Programme in Science and Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2019-11-27
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-201911075819
https://urn.fi/URN:NBN:fi:tuni-201911075819
Tiivistelmä
The aim of thesis was to understand how lignins and hemicelluloses work as plasticizers, dispersing agents, emulsifiers and stabilizer in dispersion applications from the chemistry point of view. An alkali-O2 oxidation (LigniOx) of lignins was discussed in more detail because relevance to the applied part of this thesis.
In the applied part, two organosolv and soda lignins provided by Fortum, and oxidized by VTT Technical Research Centre of Finland, were evaluated in special carbon black and titan dioxide dispersions. Rheological measurements and optical microscopy were used as analysis methods. The aim of the applied part was to increase the knowledge of the new type of lignin-based dispersants and give background information for the development of Fortum’s lignins as dispersants in paint, coating, ink, plastic and other dispersion-related applications.
The research literature of lignins and hemicelluloses in different dispersion-related applications is broad. However, this does not directly translate to broad amount of developed and existing applications. Hemicelluloses have chemical analogies, such as gums and other hydrocolloids, which are commercially used for example as texture modifiers in foods and cosmetics. The public research of hemicelluloses as dispersants and texture modifiers in other dispersion applications than foods and cosmetics is however still in early phases.
The research of new lignin-based dispersants has focused on the applications in which lignosulfonates are already commercially utilized, such as cement plasticization. In these cases, the new lignin-based dispersant should perform better than lignosulfonates, especially if the production costs are higher for these new lignin-based dispersants. Alternatively, new dispersion applications should be found, in which lignosulfonates have not been used or do not work well.
In the applied part of the thesis, the rheological measurements and complementary optical microscopy imaging showed that alkali-O2 oxidized (LigniOx) lignins have potential as dispersants especially in carbon black dispersions and to an extent in the titan dioxide dispersions. All the oxidized organosolv and soda lignins had very similar behavior in these dispersions. The optimum amounts of lignin dispersants (7.5-20 wt% lignin of carbon black) in carbon black dispersions were slightly lower compared to commercial lignosulfonate and synthetic polymer references. The lignin dispersants were especially suitable for the special carbon black dispersions because good dispersing performance and no visible change in the color of the dispersions even with high amounts of lignin dispersants.
In the case of titan dioxide dispersions, the required amount of lignin dispersants was lower (0.125-0.5 wt% lignin of titan dioxide) compared to the references. However, the brown color of lignin affects the color of titan dioxide dispersions to an extent and the storage stability of titan dioxide dispersions with lignin dispersants needs to be further investigated.
In the applied part, two organosolv and soda lignins provided by Fortum, and oxidized by VTT Technical Research Centre of Finland, were evaluated in special carbon black and titan dioxide dispersions. Rheological measurements and optical microscopy were used as analysis methods. The aim of the applied part was to increase the knowledge of the new type of lignin-based dispersants and give background information for the development of Fortum’s lignins as dispersants in paint, coating, ink, plastic and other dispersion-related applications.
The research literature of lignins and hemicelluloses in different dispersion-related applications is broad. However, this does not directly translate to broad amount of developed and existing applications. Hemicelluloses have chemical analogies, such as gums and other hydrocolloids, which are commercially used for example as texture modifiers in foods and cosmetics. The public research of hemicelluloses as dispersants and texture modifiers in other dispersion applications than foods and cosmetics is however still in early phases.
The research of new lignin-based dispersants has focused on the applications in which lignosulfonates are already commercially utilized, such as cement plasticization. In these cases, the new lignin-based dispersant should perform better than lignosulfonates, especially if the production costs are higher for these new lignin-based dispersants. Alternatively, new dispersion applications should be found, in which lignosulfonates have not been used or do not work well.
In the applied part of the thesis, the rheological measurements and complementary optical microscopy imaging showed that alkali-O2 oxidized (LigniOx) lignins have potential as dispersants especially in carbon black dispersions and to an extent in the titan dioxide dispersions. All the oxidized organosolv and soda lignins had very similar behavior in these dispersions. The optimum amounts of lignin dispersants (7.5-20 wt% lignin of carbon black) in carbon black dispersions were slightly lower compared to commercial lignosulfonate and synthetic polymer references. The lignin dispersants were especially suitable for the special carbon black dispersions because good dispersing performance and no visible change in the color of the dispersions even with high amounts of lignin dispersants.
In the case of titan dioxide dispersions, the required amount of lignin dispersants was lower (0.125-0.5 wt% lignin of titan dioxide) compared to the references. However, the brown color of lignin affects the color of titan dioxide dispersions to an extent and the storage stability of titan dioxide dispersions with lignin dispersants needs to be further investigated.