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Publications (10 of 39) Show all publications
Francon, H., Benselfelt, T., Granberg, H., Larsson, P. A. & Wågberg, L. (2019). 3D printable nanocellulose aerogels via a green crosslinking approach and a facile evaporation procedure. Paper presented at National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL. Abstracts of Papers of the American Chemical Society, 257
Open this publication in new window or tab >>3D printable nanocellulose aerogels via a green crosslinking approach and a facile evaporation procedure
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2019 (English)In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-257628 (URN)000478860502770 ()
Conference
National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL
Note

QC 20190902

Available from: 2019-09-02 Created: 2019-09-02 Last updated: 2019-09-02Bibliographically approved
Larsson, P. A., Riazanova, A., Ciftci, G. C., Rojas, R., Ovrebo, H. H., Wågberg, L. & Berglund, L. (2019). Towards optimised size distribution in commercial microfibrillated cellulose: a fractionation approach. Cellulose (London), 26(3), 1565-1575
Open this publication in new window or tab >>Towards optimised size distribution in commercial microfibrillated cellulose: a fractionation approach
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2019 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 3, p. 1565-1575Article in journal (Refereed) Published
Abstract [en]

For the successful commercialisation of microfibrillated cellulose (MFC) it is of utmost importance to carefully characterise the constituent cellulose particles. This could for instance lead to the development of MFC grades with size distributions tailored for specific applications. Characterization of MFC is challenging due to the heterogeneous chemical and structural nature of MFC. This study describes a fractionation approach that combines two steps of physical sieving of larger particles and a final centrifugation step to separate out the smallest, colloidally stable particles, resulting in four distinctly different size fractions. The properties, such as size and charge, of each fraction were studied, as well as MFC filtration time, film formation, and film properties (mechanical and optical). It was found that virtually all surface charges, determined by polyelectrolyte adsorption, are located in the colloidally stable fraction of the MFC. In addition, the amount of available surface charges can be used as an estimate of the degree of fibrillation of the MFC. The partly fibrillated particles frequently displayed a branching, fringed morphology. Mechanical testing of films from the different fractions revealed that the removal of large particles may be more important for strength than achieving full fibrillation. Overall, this study demonstrates that by controlling the size distribution in MFC grades, property profiles including dewatering time to make films by filtration, rheology, film strength and optical transmittance could be optimised. [GRAPHICS] .

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Cellulose nanofibrils, Cellulose films, Fractionation, Microfibrillated cellulose, Nanocellulose, Nanopaper
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-247842 (URN)10.1007/s10570-018-2214-4 (DOI)000460617900011 ()2-s2.0-85059322104 (Scopus ID)
Note

QC 20190326

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-05-21Bibliographically approved
López Durán, V., Larsson, P. A. & Wågberg, L. (2018). Chemical modification of cellulose-rich fibres to clarify the influence of the chemical structure on the physical and mechanical properties of cellulose fibres and thereof made sheets. Carbohydrate Polymers, 182, 1-7
Open this publication in new window or tab >>Chemical modification of cellulose-rich fibres to clarify the influence of the chemical structure on the physical and mechanical properties of cellulose fibres and thereof made sheets
2018 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 182, p. 1-7Article in journal (Refereed) Published
Abstract [en]

Despite the different chemical approaches used earlier to increase the ductility of fibre-based materials, it has not been possible to link the chemical modification to their mechanical performance. In this study, cellulose fibres have been modified by periodate oxidation, alone or followed either by borohydride reduction, reductive amination or chlorite oxidation. In addition, TEMPO oxidation, and TEMPO oxidation in combination with periodate oxidation and further reduction with sodium borohydride have also been studied. The objective was to gain understanding of the influence of different functional groups on the mechanical and structural properties of handsheets made from the modified fibres. It was found that the modifications studied improved the tensile strength of the fibres to different extents, but that only periodate oxidation followed by borohydride reduction provided more ductile fibre materials. Changes in density, water-holding capacity and mechanical performance were also quantified and all are dependent on the functional group introduced.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Borohydride reduction, Cellulose fibres, Chemical modification, Chlorite oxidation, Periodate oxidation, Structure-property relationship, TEMPO oxidation
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-218909 (URN)10.1016/j.carbpol.2017.11.006 (DOI)000418661800001 ()2-s2.0-85032914983 (Scopus ID)
Funder
VINNOVA
Note

QC 20171201

Available from: 2017-12-01 Created: 2017-12-01 Last updated: 2018-07-11Bibliographically approved
Larsson, P. A., Linvill, E., Lo Re, G., Östlund, S. & Wågberg, L. (2018). Ductile and thermoplastic cellulose with novel application and design opportunities. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA. Abstracts of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>Ductile and thermoplastic cellulose with novel application and design opportunities
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2018 (English)In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-240162 (URN)000435537703079 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA
Note

QC 20190111

Available from: 2019-01-11 Created: 2019-01-11 Last updated: 2019-05-10Bibliographically approved
López Durán, V., Hellwig, J., Larsson, P. A. & Wågberg, L. (2018). Effect of Chemical Functionality on the Mechanical and Barrier Performance of Nanocellulose Films. ACS APPLIED NANO MATERIALS, 1(4), 1959-1967
Open this publication in new window or tab >>Effect of Chemical Functionality on the Mechanical and Barrier Performance of Nanocellulose Films
2018 (English)In: ACS APPLIED NANO MATERIALS, ISSN 2574-0970, Vol. 1, no 4, p. 1959-1967Article in journal (Refereed) Published
Abstract [en]

In the present work, we have partially modified fibrils chemically to eate a shell of derivatized cellulose that surrounds the crystalline re of native cellulose. Through the different modifications, we aimed creating a toolbox to enable the properties of CNF materials and terials containing CNFs to be tuned to meet specific material demands. total, nine different chemical modifications using different ueous-based procedures were used as chemical pretreatments before CNF oduction through homogenization. Eight of these modifications included riodate oxidation with an average of 27% of the anhydroglucose units the cellulose chain being cleaved into dialdehydes. The presence of dehydes then facilitated a conversion to other functional groups.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
Keywords
borohydride reduction, chemical modification, chlorite oxidation, ductility, nanocellulose, periodate oxidation, reductive amination, TEMPO oxidation
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-248115 (URN)10.1021/acsanm.8b00452 (DOI)000461400500061 ()
Note

QC 20190426

Available from: 2019-04-26 Created: 2019-04-26 Last updated: 2019-05-20Bibliographically approved
López Durán, V., Erlandsson, J., Wågberg, L. & Larsson, P. A. (2018). Novel, Cellulose-Based, Lightweight, Wet-Resilient Materials with Tunable Porosity, Density, and Strength. ACS SUSTAINABLE CHEMISTRY & ENGINEERING, 6(8), 9951-9957
Open this publication in new window or tab >>Novel, Cellulose-Based, Lightweight, Wet-Resilient Materials with Tunable Porosity, Density, and Strength
2018 (English)In: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 6, no 8, p. 9951-9957Article in journal (Refereed) Published
Abstract [en]

Highly porous materials with low density were developed from chemically modified cellulose fibers using solvent-exchange and air drying. Periodate oxidation was initially performed to introduce aldehydes into the cellulose chain, which were then further oxidized to carboxyl groups by chlorite oxidation. Low-density materials were finally achieved by a second periodate oxidation under which the fibers self-assembled into porous fibrous networks. Following a solvent exchange to acetone, these networks could be air-dried without shrinkage. The properties of the materials were tuned by mechanical mixing with a high intensity mixer for different times prior to the second periodate oxidation, which resulted in porosities between 94.4% and 96.3% (i.e., densities between 54 and 82 kg/m(3)). The compressive strength of the materials was between 400 and 1600 kPa in the dry state and between 20 and 50 kPa in the wet state. It was also observed that in the wet state the fiber networks could be compressed up to 80% while still being able to recover their shape. These networks are highly interesting for use in different types of absorption products, and since they also have a high wet integrity, they can be modified with physical methods for different high-value-added end-use applications.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
Keywords
Ambient drying, Cellulose, Chemical modification, Chlorite oxidation, Lightweight material, Periodate oxidation
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-234192 (URN)10.1021/acssuschemeng.8b01165 (DOI)000441475500049 ()2-s2.0-85049192536 (Scopus ID)
Note

QC 20181001

Available from: 2018-10-01 Created: 2018-10-01 Last updated: 2019-09-13Bibliographically approved
Erlandsson, J., Pettersson, T., Ingverud, T., Granberg, H., Larsson, P. A., Malkoch, M. & Wågberg, L. (2018). On the mechanism behind freezing-induced chemical crosslinking in ice-templated cellulose nanofibril aerogels. Journal of Materials Chemistry A, 6(40), 19371-19380
Open this publication in new window or tab >>On the mechanism behind freezing-induced chemical crosslinking in ice-templated cellulose nanofibril aerogels
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2018 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 40, p. 19371-19380Article in journal (Refereed) Published
Abstract [en]

The underlying mechanism related to freezing-induced crosslinking of aldehyde-containing cellulose nanofibrils (CNFs) has been investigated, and the critical parameters behind this process have been identified. The aldehydes introduced by periodate oxidation allows for formation of hemiacetal bonds between the CNFs provided the fibrils are in sufficiently close contact before the water is removed. This is achieved during the freezing process where the cellulose components are initially separated, and the growth of ice crystals forces the CNFs to come into contact in the thin lamellae between the ice crystals. The crosslinked 3-D structure of the CNFs can subsequently be dried under ambient conditions after solvent exchange and still maintain a remarkably low density of 35 kg m-3, i.e. a porosity greater than 98%. A lower critical amount of aldehydes, 0.6 mmol g-1, was found necessary in order to generate a crosslinked 3-D CNF structure of sufficient strength not to collapse during the ambient drying. The chemical stability of the 3-D structure can be further enhanced by converting the hemiacetals to acetals by treatment with an alcohol under acidic conditions.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
Keywords
Aerogels, Aldehydes, Cellulose, Chemical stability, Crosslinking, Freezing, Nanofibers, Acidic conditions, Ambient conditions, Cellulose nanofibrils (CNFs), Chemical cross-linking, Freezing process, Lower critical, Periodate oxidation, Solvent exchanges, Ice
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-247488 (URN)10.1039/c8ta06319b (DOI)000448413100008 ()2-s2.0-85055128762 (Scopus ID)
Note

QC 20190405

Available from: 2019-04-05 Created: 2019-04-05 Last updated: 2019-09-13Bibliographically approved
Salmén, L. & Larsson, P. A. (2018). On the origin of sorption hysteresis in cellulosic materials. Carbohydrate Polymers, 182, 15-20
Open this publication in new window or tab >>On the origin of sorption hysteresis in cellulosic materials
2018 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 182, p. 15-20Article in journal (Refereed) Published
Abstract [en]

Moisture sorption and moisture sorption hysteresis of carbohydrates are phenomena which affect the utilisation of products made thereof. Although extensively studied, there is still no consensus regarding the mechanisms behind sorption hysteresis. Attempts have been made to link the behaviour to molecular properties, in particular to softening properties, and the moisture sorption hysteresis has therefore here been investigated by modifying cellulosic fibres to affect their softening properties. The results show that the moisture sorption hysteresis diminishes with decreasing softening temperature, and was even completely absent at the higher degrees of modification. The moisture sorption characteristics also changed from a type II sorption to a more type III sorption behaviour, a feature more prominent the higher the degree of modification and the higher the temperature. For the highest degree of modification studied the sorption characteristics changed from sorbing less water the higher the temperature to sorbing more water with increasing temperature.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Cellulose, Chemical modification, Dialcohol cellulose, Glass transition temperature, Kraft pulp, Moisture sorption, Sorption hysteresis, Temperature
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-218910 (URN)10.1016/j.carbpol.2017.11.005 (DOI)000418661800003 ()2-s2.0-85032968676 (Scopus ID)
Funder
VINNOVA
Note

QC 20171201

Available from: 2017-12-01 Created: 2017-12-01 Last updated: 2018-01-11Bibliographically approved
Lombardo, S., Chen, P., Larsson, P. A., Thielemans, W., Wohlert, J. & Svagan, A. J. (2018). Toward Improved Understanding of the Interactions between Poorly Soluble Drugs and Cellulose Nanofibers. Langmuir, 34(19), 5464-5473
Open this publication in new window or tab >>Toward Improved Understanding of the Interactions between Poorly Soluble Drugs and Cellulose Nanofibers
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2018 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 34, no 19, p. 5464-5473Article in journal (Refereed) Published
Abstract [en]

Cellulose nanofibers (CNFs) have interesting physicochemical and colloidal properties that have been recently exploited in novel drug-delivery systems for tailored release of poorly soluble drugs. The morphology and release kinetics of such drug-delivery systems heavily relied on the drug-CNF interactions; however, in-depth understanding of the interactions was lacking. Herein, the interactions between a poorly soluble model drug molecule, furosemide, and cationic cellulose nanofibers with two different degrees of substitution are studied by sorption experiments, Fourier transform infrared spectroscopy, and molecular dynamics (MD) simulation. Both MD simulations and experimental results confirmed the spontaneous sorption of drug onto CNF. Simulations further showed that adsorption occurred by the flat aryl ring of furosemide. The spontaneous sorption was commensurate with large entropy gains as a result of release of surface-bound water. Association between furosemide molecules furthermore enabled surface precipitation as indicated by both simulations and experiments. Finally, sorption was also found not to be driven by charge neutralization, between positive CNF surface charges and the furosemide negative charge, so that surface area is the single most important parameter determining the amount of sorbed drug. An optimized CNF-furosemide drug-delivery vehicle thus needs to have a maximized specific surface area irrespective of the surface charge with which it is achieved. The findings also provide important insights into the design principles of CNF-based filters suitable for removal of poorly soluble drugs from wastewater.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-228736 (URN)10.1021/acs.langmuir.8b00531 (DOI)000432417700013 ()2-s2.0-85047114826 (Scopus ID)
Note

QC 20180529

Available from: 2018-05-29 Created: 2018-05-29 Last updated: 2018-06-19Bibliographically approved
Hollertz, R., López Durán, V., Larsson, P. A. & Wågberg, L. (2017). Chemically modified cellulose micro- and nanofibrils as paper-strength additives. Cellulose (London), 24(9), 3883-3899
Open this publication in new window or tab >>Chemically modified cellulose micro- and nanofibrils as paper-strength additives
2017 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, no 9, p. 3883-3899Article in journal (Refereed) Published
Abstract [en]

Chemically modified cellulose micro- and nanofibrils were successfully used as paper strength additives. Three different kinds of cellulose nanofibrils (CNFs) were studied: carboxymethylated CNFs, periodate-oxidised carboxymethylated CNFs and dopamine-grafted carboxymethylated CNFs, all prepared from bleached chemical fibres of dissolving grade, and one microfibrillated cellulose from unbleached kraft fibres. In addition to mechanical characterization of the final paper sheets the fibril retention, sheet density and sheet morphology were also studied as a function of addition of the four different cellulose fibrils. In general, the cellulose fibrils, when used as additives, significantly increased the tensile strength, Young’s modulus and strain-at-break of the paper sheets. The effects of the different fibrils on these properties were compared and evaluated and used to analyse the underlying mechanisms behind the strengthening effect. The strength-enhancing effect was most pronounced for the periodate-oxidised CNFs when they were added together with polyvinyl amine (PVAm) or poly(dimethyldiallylammonium chloride) (pDADMAC). The addition of periodate-oxidised CNFs, with pDADMAC as retention aid, resulted in a 37% increase in tensile strength at a 2 wt% addition and an 89% increase at a 15 wt% addition (from 67 to 92 and 125 kNm/kg, respectively) compared to a reference with only pDADMAC. Wet-strong sheets with a wet tensile index of 30 kNm/kg were also obtained when periodate-oxidised CNFs and PVAm were combined. This significant increase in wet strength is suggested to be the result of a formation of cross-links between the aldehyde groups, introduced by the periodate oxidation, and hydroxyl groups on the lignocellulosic fibres and the primary amines of PVAm. Even though less significant, there was also an increase in wet tensile strength when pDADMAC was used together with periodate-oxidised fibrils which shows that the aldehyde groups are able to increase the wet strength without the presence of the primary amines of the PVAm. As an alternative method to strengthen the fibre network, carboxymethylated CNFs grafted with dopamine, by an ethyl dimethylaminopropyl carbodiimide coupling, were used as a strength additive. When used as an additive, these CNFs showed a strong propensity to form films on and around the fibres and significantly increased the mechanical properties of the sheets. Their addition resulted in an increase in the Young´s modulus by 41%, from 5.1 to 7.2 GPa, and an increase in the tensile strength index of 98% (from 53 to 105 kNm/kg) with 5 wt% retained dopamine-grafted CNFs.

Place, publisher, year, edition, pages
Springer Netherlands, 2017
Keywords
Carboxymethylation, Cellulose nanofibrils, Dopamine grafting, Paper strength, Periodate oxidation, Strength additives, Additives, Aldehydes, Amines, Cellulose, Fibers, Grafting (chemical), Nanofibers, Neurophysiology, Oxidation, Paper products, Polyvinyl chlorides, Paper strengths, Tensile strength
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-218823 (URN)10.1007/s10570-017-1387-6 (DOI)000407437000020 ()2-s2.0-85021744663 (Scopus ID)
Note

QC 20180117

Available from: 2018-01-17 Created: 2018-01-17 Last updated: 2019-10-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7410-0333

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