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Mot hållbara nanokompositer
KTH, School of Chemical Science and Engineering (CHE).
2017 (Swedish)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Towards Sustainable Nanocomposites (English)
Abstract [en]

Reducing the usage of fossil based materials is an important part of the work to reach a sustainable society. Using renewable components in fossil based materials could mean a step towards total replacement of these. Microfibrillated cellulose (MFC) is a potential candidate in this context.

In this master thesis, the surface of MFC was covalently modified by polymerization in order to lower its inherent hydrophilicity. The modified MFC was then used as a component in composite materials together with plastic matrices, processed by extrusion.

Analysis with FTIR (Fourier transform infrared spectroscopy) demonstrated the formation of a polymer coating on the surface of MFC. Contact angle measurements showed that modified MFC was more hydrophobic compared to unmodified MFC.

Thermal analysis by TGA (Thermogravimetric analysis) of the composites showed that the heat resistance was deteriorated, the composites started to degrade at a lower temperature compared to pure matrix. Analysis by DSC (Differential scanning calorimetry) showed that the composites exhibited a thermoplastic behavior with both melting and crystallization transitions. The mechanical properties Young’s modulus, tensile strain at break and tensile stress at break decreased when modified MFC was introduced into the structure of the matrices. The exception was Young’s modulus for composites produced with a certain type of plastic matrix which then increased substantially with increasing amount modified MFC. Reference samples with this plastic matrix and unmodified MFC showed the same trend.

Abstract [sv]

Att minska användningen av fossilbaserade material är en viktig del av arbetet mot att uppnå ett hållbart samhälle. Genom att använda förnyelsebara komponenter i fossilbaserade material skulle det kunna innebära ett steg på vägen mot att byta ut dessa helt. Mikrofibrillerad cellulosa (MFC) är en möjlig kandidat i dessa sammanhang.

I detta examensarbete modifierades ytan på MFC kovalent genom polymerisation för att minska dess naturliga hydrofilicitet. Den modifierade MFC:en användes sedan som en komponent i olika kompositmaterial tillsammans med plastmatriser, bearbetade genom extrudering.

Analys med FTIR (Fourier transform infrared spectroscopy) påvisade bildandet av en polymerfilm på ytan av MFC. Kontaktvinkelmätningar visade att modifierad MFC var mer hydrofob jämfört med omodifierad MFC.

Termisk analys med TGA (Thermogravimetric analysis) på kompositerna visade att värmebeständigheten försämrades, kompositerna började degraderas vid en lägre temperatur jämfört med den rena matrisen. Analys med DSC (Differential scanning calorimetry) visade att kompositerna uppvisade ett termoplastiskt beteende med både smält- och kristallisationsövergångar. De mekaniska egenskaperna Young’s modulen, töjning vid brott och spänning vid brott minskade när modifierad MFC introducerades till matrisstrukturen. Undantaget var Young’s modulen för kompositer tillverkade med en viss typ av plastmatris som då ökade väsentligt med ökad mängd tillsatt modifierad MFC. Referensprover med denna plastmatris och omodifierad MFC visade på samma trend.

Place, publisher, year, edition, pages
2017. , p. 79
Keywords [en]
nanocellulose, composite, surface modification, polymerization
Keywords [sv]
nanocellulosa, komposit, ytmodifiering, polymerisation
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:kth:diva-215087OAI: oai:DiVA.org:kth-215087DiVA, id: diva2:1146167
Available from: 2017-10-02 Created: 2017-10-02 Last updated: 2017-10-02Bibliographically approved

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