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Author:Hakalahti, Minna
Title:Preparation of cellulose-based filtration membranes with stimuli-responsive properties
Selluloosapohjaisten heräteherkkien suodatinmembraanien valmistus
Publication type:Master's thesis
Publication year:2013
Pages:vi + 64 + [7]      Language:   eng
Department/School:Kemian laitos
Main subject:Polymeeriteknologia   (Kem-100)
Supervisor:Seppälä, Jukka
Instructor:Setälä. Harri
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark Aalto  2060   | Archive
Keywords:stimuli-responsive polymers
filtration membranes
cellulose
grafting
surface functionalization
PNIPAM
heräteherkät polymeerit
suodatusmembraanit
selluloosa
oksastus
pintafunktionalisointi
Abstract (eng): Membranes are major components of many water-intensive industrial processes.
Fouling, one of membrane technology's main challenges, decreases permeability and increases the need for cleaning.
Anti-fouling properties of membranes can be enhanced for example by surface treatment by chemical modification.
Additionally, smart cleaning behaviour can be achieved by incorporating stimuli-responsive polymers onto filtration membrane surfaces.
When fouling occurs, membrane pores can be temporarily and reversibly enlarged by an external stimulus to aid cleaning.

In this study, polysaccharides were chemically modified by adding allylic double bonds to their backbone.
Furthermore, these highly reactive double bonds were used for crosslinking and grafting poly(N-isopropylacrylamide) (PNIPAM) to integrate a temperature-responsive property.
Hydrogel and membrane samples were prepared.
13C NMR, SEM, chromatographic bromine analysis, DSC, elementary analysis and CR-filtration tests were used to characterize prepared samples.

Results of this study demonstrated that cellulosic materials were modified into cellulosic derivatives containing moderate amounts of allyl double bonds.
These derivatives were capable of crosslinking and could be grafted with PNIPAM with high grafting efficiencies.
LCST of PNIPAM altered slightly depending on the matrix material.
Commercial membranes and filter materials were modified by applying these cellulosic derivatives.
Stable coatings that changed the surface morphologies were formed, but a temperature-response was not observed around the LCST of PNIPAM in permeability measurements.
Abstract (fin): Membraaneja käytetään teollisuudessa prosessivesien suodattamiseen.
Membraanien ja suodattimien likaantuminen on yksi membraaniteknologian suurimmista haasteista.
Suodattimen pinnalle kertyvä lika tukkii huokoset, pienentää läpivirtausta ja heikentää muita suodatinominaisuuksia.
Kemiallisen muokkauksen avulla suodattimen pintaa voidaan muokata likaantumista estävien tai puhdistamista helpottavien ominaisuuksien parantamiseksi.
Yksi tapa on käyttää suodattimissa heräteherkkiä polymeerejä, joiden avulla membraanin huokoskokoa voidaan säädellä ulkoisen ärsykkeen avulla.

Tässä työssä polysakkarideja muokattiin kemiallisesti liittämällä niihin allyyliryhmiä.
Näitä polysakkaridijohdannaisia käytettiin ristisilloittajina ja jatkomuokattiin oksastamalla niihin lämpöherkkää poly(N-isopropyyliakryyliamidia) (PNIPAM).
Valmistettuja hydrogeeli- ja membraaninäytteitä analysoitiin 13C NMR-, SEM-, DSC- ja CR-suodinkoemenetelmillä.
Lisaksi analysoinnissa ja karakterisoinnissa käytettiin kromatografista bromianalyysia ja alkuaineanalyysia.

Työn tulokset osoittivat, että valmistetut polysakkaridijohdannaiset sisälsivät allyyliryhmiä ja pystyivät ristisilloittumaan itsensä kanssa.
Lisäksi niihin oli mahdollista oksastaa PNIPAM:ia tehokkaasti.
PNIPAM:in lämpötilaherkkä alue muuttui hieman riippuen siitä, mihin matriisiin se oli oksastettu.
Kaupallisia membraaneja ja suodatusmateriaaleja muokattiin valmistetuilla polysakkaridijohdannaisilla.
Pysyvät pinnoitteet muuttivat suodatinmateriaalien pintarakennetta.
PNIPAM-polymeeriin liittyvää lämpötilavastetta ei kuitenkaan havaittu virtausmittauksissa.
ED:2013-04-24
INSSI record number: 46130
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