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End-functionalization of cellulose nanocrystals

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Lokanathan, Arcot
dc.contributor.author Lundahl, Meri
dc.date.accessioned 2014-06-25T08:16:25Z
dc.date.available 2014-06-25T08:16:25Z
dc.date.issued 2014-06-03
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/13440
dc.description.abstract Regioselective modification of nanocelluloses can have intriguing applications in self-assembled material synthesis. In this thesis, cellulose nanocrystals (CNC) were selectively functionalized at their reducing ends with thiol and maleimide groups. For thiol end-functionalization, a protocol was developed based on NHS/EDC-catalyzed coupling of NaClO2-oxidized CNCs with NH2 (CH2)6 SH in water. Maleimide end-functionalization was achieved by reacting end-thiolated CNCs (CNC SH) with a homobifunctional maleimide crosslinker in ethanol. Among the alternative protocols compared, end-thiolation was found to proceed most effectively in high ionic strength, with an EDC:NHS molar ratio of 10:1. Thus prepared CNC SH adsorbed on gold as a fairly flexible layer in quartz-crystal microbalance with dissipation (QCM D). Complying with a previous study, these results validate CNC SH preparation via a faster reaction in simpler conditions than before. The results of maleimide end-functionalization suggested 50:1 as the optimal molar ratio between the maleimide crosslinker and thiols of CNC SH. This modification lead to a slight adsorption of this sample on a surface covered with thiol groups in QCM D. However, the adsorption remained low, probably due to limited yield of the functionalization. In the future, control experiments are necessary to adequately validate the developed end-thiolation method. In addition, the maleimide end-functionalization needs to be more thoroughly optimized, particularly in ethanol media. With these improvements, both functionalization techniques could become feasible routes to prepare CNCs that attach to other molecules and surfaces in a controlled orientation. en
dc.format.extent 61+2
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.title End-functionalization of cellulose nanocrystals en
dc.type G2 Pro gradu, diplomityö en
dc.contributor.school Kemian tekniikan korkeakoulu fi
dc.subject.keyword cellulose nanocrystals en
dc.subject.keyword reducing end en
dc.subject.keyword functionalization en
dc.identifier.urn URN:NBN:fi:aalto-201406252172
dc.programme.major Renewable Materials Engineering fi
dc.programme.mcode KM3002 fi
dc.type.ontasot Master's thesis en
dc.type.ontasot Diplomityö fi
dc.contributor.supervisor Laine, Janne
dc.programme Master's Programme in Bioproduct Technology fi
dc.location PK fi
local.aalto.openaccess yes
local.aalto.digifolder Aalto_90939
dc.rights.accesslevel openAccess
local.aalto.idinssi 49381
dc.type.publication masterThesis
dc.type.okm G2 Pro gradu, diplomityö

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