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Author:Hartikainen, Eeva
Title:Solution state of cellulose in ionic liquids - a rheological study
Ionisiin nesteisiin liuotetun selluloosan liuosolomuoto - reologinen tutkimus
Publication type:Master's thesis
Publication year:2013
Pages:74 s. + liitt. 1      Language:   eng
Department/School:Kemian tekniikan korkeakoulu
Main subject:Sellutekniikka   (P3002)
Supervisor:Sixta, Herbert
Instructor:Hummel, Michael
Electronic version URL: http://urn.fi/URN:NBN:fi:aalto-201310167727
OEVS:
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Location:P1 Ark Aalto  2323   | Archive
Keywords:cellulose
ionic liquids
shear rheology
extensional rheology
oscillatory rheology
intrinsic viscosity
selluloosa
ioniset nesteet
leikkausreologia
venymäreologia
oskilloiva reologia
rajaviskositeetti
Abstract (eng):The purpose of this study was to investigate the rheological properties of cellulose-ionic liquid (IL) solutions.
The objective of the literature part was to explain the theory behind the rheological experiments.
It includes the literature review about ionic liquids and the relevant theories about shear and extensional rheology considering the experimental part.
The motivation behind the whole study lies in fiber spinning, because via rheology, information about spinnability can be gained.

For the experiments, different cellulose-ionic liquids solutions were prepared by dissolving three different pulps in five different ionic liquids.
Pulps were prehy-drolysis-kraft (PHK) dissolving pulp from Eucalyptus urograndis (468 mL/g), cold caustic extracted prehydrolysis-kraft softwood dissolving pulp (PHK+CCE) (572 mL/g) and cotton linters pulp (CLP) (965 mL/g).
Ionic liquids were 1-ethyl-3-methylimidazolium acetate ([emim]OAc), 1-ethyl-3-methylimidazolium dimethyl phosphate ([emim]dmp), 1,5-diazabicyclo[4.3.0]non-5-ene acetate ([DBNH]OAc), 1,5-diazabicyclo[4.3.0]non-5-ene propionate ([DBNH]EtCO2 or [DBNH]propionate) and 1-methyl-1,5-diazabicyclo[4.3.0]non-5-ene dimethyl phosphate ([mDBN]dmp).
[Emim]OAc and [DBNH]OAc were the most promising ionic liquids regarding fiber spinning, thus, these two ILs were studied in more detail.

Shear rheological measurements were performed using a modular compact rhe-ometer (MCR).
Shear thinning behavior was found, and the main parameters affecting the rheological properties were concentration, temperature and raw material properties.
One of the most important parameters investigated in this study is intrinsic viscosity.
A dependence between concentration, temperature, molecular mass and the intrinsic viscosity was found.
Extensional behavior of cellulose-IL solutions was investigated using a capillary break-up extensional rheometer (CaBER).
Temperature and concentration affected the relaxation time and the mid-filament diameter of the thinning liquid.
In addition, the visco-elastic behavior of the solutions was studied with an oscillatory rheological test.
The storage and loss moduli were determined, and dependence with temperature was found.
Abstract (fin):Tämän tutkimuksen tarkoituksena oli tutkia ionisiin nesteisiin liuotettujen sellu-loosaliuosten reologisia ominaisuuksia.
Kirjallisuusosan päämääränä oli selittää teoria, johon reologiset kokeet pohjautuivat.
Se sisältää kirjallisuuskatsauksen ionisista nesteistä sekä kokeellisen osan kannalta oleelliset teoriat leikkaus- ja venymäreologiasta (engl. shear and extensional rheology).
Tutkimuksen motivaatio oli kuitujen kehruu, sillä reologian avulla on mahdollista saada tietoa kuitujen kehrättävyydestä.

Kokeita varten valmistettiin erilaisia selluloosa-ioninen neste-liuoksia liuottamalla kolmea eri kuitumassaa viiteen eri ioniseen nesteeseen.
Käytetyt massat olivat PHK-liukosellu (Eucalyptus urograndis, 468 mL/g), kylmäalkaliuutettu PHK-havuliukosellu (572 mL/g) ja puuvillakuitu (965 mL/g).
Ioniset nesteet olivat [emim]OAc, [emim]dmp, [DBNH]OAc, [DBNH]EtCO2 ja [mDBN]dmp.
[Emim]OAc ja [DBNH]OAc vaikuttivat lupaavimmilta ionisilta nesteiltä kuitujen kehräämisen kannalta, joten niihin on perehdytty tarkemmin.

Leikkausreologiset mittaukset tehtiin modular compact reometrilla (MCR).
Leikkausohenevaa (engl. shear thinning) käyttäytymistä havaittiin ja pääparametrit, joiden huomattiin vaikuttavan reologisiin ominaisuuksiin, olivat konsentraatio, lämpötila ja raaka-aineden ominaisuudet.
Yksi tärkeimmistä parametreistä tässä tutkimuksessa on rajaviskositeetti.
Riippuvuus konsentraation, lämpötilan, molekyylimassan ja rajaviskositeetin välillä löydettiin.
Selluloosa-ioninen neste-liuosten venymäkäyttäytymistä tutkittiin capillary break-up extensional reometrilla (CaBER).
Lämpöitlan ja konsentraation huomattiin vaikuttavan relaksaatioaikaan ja kapenevan filamentin halkaisijaan.
Myös liuosten viskoelastista käyttäytymistä tutkittiin oskilloivan reologian avulla.
Storage ja loss moduulit määritettiin, ja niiden sekä lämpötilan välille löydettiin riippuvuus.
ED:2013-12-02
INSSI record number: 48112
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