Nanocellulose based hydrogel with tailored rheological properties by tuning the network architecture

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Heise, Katja Araba, Taofik 2019-06-23T15:08:42Z 2019-06-23T15:08:42Z 2019-06-18
dc.description.abstract Cellulose nanofibrils (CNFs) is materializing into biomedical application research. Weak CNF hydrogels have been modified with various compounds in order to change the network architecture of this abundant biopolymer. This thesis seeks to understand the effect of CNF solids content in a coupling reaction. CNF was covalently modified with an amine containing thermoresponsive peptide terminated with tri (ethylene glycol) oxide and ionically modified with a quaternary ammonium containing peptide terminated with tri (ethylene glycol) oxide. Furthermore, the rheological behaviour of the CNF gels pre and post modification with the thermoresponsive chains was investigated. In the amide bond formation reaction on CNF, the highest degree of substitution (DS) on CNF-COOH was observed in a reaction condition with very low fibril consistency and the lowest DS was observed in a reaction condition with high fibril consistency, subsequently short time interval within reagent introduction. Moreover, in the ionic bond formation, higher DS was observed in reactions carried out at room temperature compared to the reactions done at higher temperature. CNF gels showed an elastic response throughout the measurement. However, covalently and electrostatically modified CNFs displayed a more solid-like character even at high frequency. Furthermore, unlike CNF gels that lose viscosity at higher frequency and temperature, the covalently modified CNF gels got stiffer with increasing temperature and the electrostatically modified CNF gels formed larger aggregates at higher temperatures, as observed by DLS. However, the stiffness observed in the covalently modified CNFs tend to become irreversible with decreasing temperature. en
dc.format.extent 72 + 6
dc.language.iso en en
dc.title Nanocellulose based hydrogel with tailored rheological properties by tuning the network architecture en
dc.type G2 Pro gradu, diplomityö fi Kemian tekniikan korkeakoulu fi
dc.subject.keyword thermoresponsive en
dc.subject.keyword shear thickening en
dc.subject.keyword TEMPO-oxidised CNF en
dc.subject.keyword rheology en
dc.identifier.urn URN:NBN:fi:aalto-201906234038
dc.programme.major Fiber and Polymer Engineering fi
dc.programme.mcode CHEM3024 fi
dc.type.ontasot Master's thesis en
dc.type.ontasot Diplomityö fi
dc.contributor.supervisor Kontturi, Eero
dc.programme Master's Programme in Chemical, Biochemical and Materials Engineering fi
dc.location PK fi
local.aalto.electroniconly yes
local.aalto.openaccess no

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