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Esterification and hydrolysis of cellulose using oxalic acid dihydrate in a solvent-free reaction suitable for preparation of surface-functionalised cellulose nanocrystals with high yield
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.ORCID iD: 0000-0002-7055-1057
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.ORCID iD: 0000-0001-6263-8403
2017 (English)In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 19, p. 5564-5567Article in journal (Refereed) Published
Abstract [en]

A one-pot esterification and hydrolysis of cellulose was carried outby treating cellulose fibres with molten oxalic acid dihydrate. Eachcellulose oxalate had a free carboxyl content above 1.2 mmol g−1and an average molecular weight of approximately 40 kDa.Aqueous suspensions of the oxalates were sonicated to preparecellulose nanocrystals with a gravimetric yield of 80.6%

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017. Vol. 19, p. 5564-5567
National Category
Paper, Pulp and Fiber Technology
Research subject
Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-219967DOI: 10.1039/c7gc02489dISI: 000417758700005Scopus ID: 2-s2.0-85035811625OAI: oai:DiVA.org:kth-219967DiVA, id: diva2:1166345
Note

QC 20171218

Available from: 2017-12-14 Created: 2017-12-14 Last updated: 2019-06-05Bibliographically approved
In thesis
1. Bio-based preparation of nanocellulose and functionalization using polyelectrolytes
Open this publication in new window or tab >>Bio-based preparation of nanocellulose and functionalization using polyelectrolytes
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [sv]

Nanocellulosa, som kan utvinnas från skogsråvara, har de senaste åren fått mycket uppmärksamhet för sina intressanta egenskaper och breda användningsområde. Studierna i denna avhandling syftar till att vidga möjligheterna att använda nanocellulosa i olika applikationer. Detta har skett genom att utveckla en ny metod för att tillverka nanocellulosa och genom att studera möjligheten att adsorbera polyelektrolyter på material av nanocellulosa för att ändra hur bakterier interagerar med dessa.

Nanocellulosan tillverkades genom att förbehandla pappersmassa med smält oxalsyra dihydrat. Reaktionsblandningen tvättades med etanol, aceton eller tetrahydrofuran innan den torkades och fibrillerades. Den resulterande nanocellulosan erhölls med högt utbyte, hade hög ytladdning (upp till 1,4 mmol g-1) och innehöll partiklar som både liknande nanofibriller och nanokristaller. Materialet visades kunna användas både för att tillverka Pickering emulsioner och tunna filmer med en styrka upp till 197 MPa, töjning upp till 5 %, E-modul upp till 10,6 GPa och syrepermeabilitet ner till 0.31 cm3 µm m‑2 dag‑kPa‑1.

Genom att adsorbera polyvinylamin och polyakrylsyra på material av nanocellulosa visades det vara möjligt att påverka mängden bakterier som fäster till materialet. Substraten bestod både av kompakta filmer och porösa aerogeler. Genom att variera ytladdningen på materialen, ytans struktur och antalet adsorberade lager av polymererna var det möjligt att tillverka material med både hög och låg bakterieadhesion. Detta gör det möjligt att anpassa material för användning antingen som kontaktaktivt- eller icke-adhesivt antibakteriellt material. Båda dessa kan vara miljövänliga alternativ till dagens antibakteriella material.

Nanocellulosa är ett material som inom snar framtid sannolikt kommer användas inom en mängd olika applikationer. För att öka mängden applikationer där nanocellulosa tillför ett stort värde är det nödvändigt att utveckla alternativa tillverkningsmetoder till dagens välkända, exempelvis, genom att använda den beskrivna oxaleringen som förbehandling. Förmågan att styra bakterieadhesionen på material av nanocellulosa ger därtill möjlighet att hitta nya användningsområden inom t.ex. hälso- och sjukvårdsbranschen.

Abstract [en]

Nanocellulose is a material which can be extracted from wood, and in recent years it has received great attention for its interesting properties and wide range of possible applications. With the aim of further expanding the applications of nanocellulose, this work has studied a new way to produce nanocellulose as well as the possibility of using polyelectrolyte adsorption to alter the interaction with bacteria of materials made from nanocellulose.

Nanocellulose was produced by a novel concurrent esterification and hydrolysis of wood pulp in molten oxalic acid dihydrate. The resulting mixture was washed using ethanol, acetone or tetrahydrofuran before the cellulose oxalate was dried and fibrillated. The nanocellulose obtained with a high yield had a high surface charge (up to 1.4 mmol g-1) and contained particles with a morphology similar to both cellulose nanocrystals and cellulose nanofibrils. The material was used to prepare both Pickering emulsions and thin films with a strength of up to 197 MPa, a strain at break of up to 5 %, a modulus of up to 10.6 GPa and an oxygen permeability as low as 0.31 cm3 µm m-2 day-1 kPa-1.

Polyelectrolyte adsorption of polyvinylamine and polyacrylic acid was used to modify materials made from nanocellulose. Materials in the form of films and aerogels were used as substrates. By altering the surface charge of the material, the surface structure and the number of layers of polyvinylamine/polyacrylic acid adsorbed, it was possible to prepare materials with both high and low bacterial adhesion. By changing the material properties it is possible to tailor materials with either contact-active or non-adhesive antibacterial properties, both of which are sustainable alternatives to the currently used antibacterial materials.

Nanocellulose is a material which in the near future will probably be used in many applications. In order to improve the suitability of nanocellulose in certain applications it will be necessary to use production methods which differ from the existing methods, for example by using oxalation as a pre-treatment. By modifying the bacterial adhesion to materials prepared from nanocellulose, new medical and health applications emerge.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2019. p. 67
Series
TRITA-CBH-FOU ; 2019:36
Keywords
cellulose nanofibrils, cellulose nanocrystals, oxalic acid, polyvinylamine, layer by layer, cellulose oxalate, antibacterial, Cellulosa nanofibriller, cellulosa nanokristaller, oxalsyra, polyvinylamin, lager på lager, cellulosa oxalat, antibakteriell
National Category
Paper, Pulp and Fiber Technology
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-252580 (URN)978-91-7873-245-6 (ISBN)
Public defence
2019-08-30, F3, Lindstedtsvägen 26, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 2019-06-05

Available from: 2019-06-05 Created: 2019-06-02 Last updated: 2019-06-05Bibliographically approved

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Ek, MonicaLi, DongfangHenschen, Jonatan

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