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Medina, L. (2019). High Clay Content Cellulose Nanocomposites for Mechanical Performance and Fire Retardancy. (Doctoral dissertation). KTH Royal Institute of Technology
Open this publication in new window or tab >>High Clay Content Cellulose Nanocomposites for Mechanical Performance and Fire Retardancy
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Materials based on wood can offer sustainable alternatives to fossil-based plastics and composites, and show interesting mechanical properties. However, the issue of their flammability is generally unresolved. In this thesis, eco-friendly, fire retardant clay-cellulose nanofibril materials are investigated. The work focuses particularly on structure-property relationships and physical properties of these materials. The thesis is structured in two parts. The first part is concerned with paper-like materials, designated as “films”. The second part discusses materials of high-porosity, so-called “foams”.

In the first part, films of clay and cellulose nanofibrils are prepared by filtration from water. The composition is systematically varied (from 0 to 100% clay) and effects on the nanostructure are investigated by synchrotron X-ray scattering, helium pycnometry and microscopy techniques. The mechanical properties of the films are determined by tensile testing, optical properties are measured by transmittance/haze tests, and strong effects of nanostructure are observed. A film with 50 wt% clay is demonstrated as a fire retardant coating on wood, by cone calorimetry testing. These films are also pre-impregnated with epoxy precursors and cured, to form ternary composites of clay, cellulose nanofibrils, and epoxy. These ternary nanocomposites show remarkably well-preserved mechanical and gas barrier properties in moist environment.

In the second part, foams of high porosity are prepared by freeze-drying a suspension based on poly(vinyl alcohol), cellulose nanofibrils, and clay. The cellular structure is investigated by scanning electron microscopy, and effects from composition and cross-linking are analyzed. The compressive properties of the foams are determined and related to their structure. Addition of poly(vinyl alcohol) influences the unique degradation and charring behavior of cellulose nanofibrils in the presence of clay so that fire retardancy is decreased.

Abstract [sv]

Material baserade på trä kan erbjuda hållbara alternativ till fossilbaserade plaster och kompositer, men deras brandegenskaper är inte särskilt goda. I denna avhandling undersöks miljövänliga, brandskyddade nanokompositer från cellulosa/nanolera. Arbetet fokuserar särskilt på struktur-egenskapsrelationer och fysikaliska egenskaper hos dessa material. Avhandlingen är uppbyggd i två delar. Den första delen handlar om pappersliknande material, betecknade som "filmer". Den andra delen diskuterar material med hög porositet, så kallade "skum".

I den första delen framställs filmer av lera (montmorillonit) och nanofibriller från cellulosa genom filtrering från vattensuspension. Kompositionen varieras systematiskt (från 0 till 100% lera) och effekter på nanostrukturen undersöks med hjälp av synkrotronröntgen, heliumpyknometri och mikroskopi. Mekaniska egenskaper hos filmerna mäts genom dragprovning, och optisk transmittans / haze där det visar sig att nanostrukturen är betydelsefull. En film med 50 viktprocent lera används som en brandskyddande ytskikt på trä, med konkalorimetri-experiment för att mäta brandegenskaper. Dessa filmer impregneras med epoxi och härdas, och bildar ternära kompositer av nanocellulosa, lera och epoxi. Dessa ternära nanokompositer visar goda mekaniska och gasbarriär-egenskaper i fuktig miljö.

I den andra delen framställs skum med hög porositet genom frystorkning av en suspension baserad på polyvinylalkohol, cellulosa nanofibriller och lera. Cellstrukturen analyseras med elektronmikroskopi, och effekter från sammansättning och tvärbindning analyseras. Skummens tryckegenskaper mäts och relateras till struktur. Polyvinylalkohol påverkar termisk nedbrytning hos nanocellulosa i närvaro av katalyserande lera så att brandhämmande egenskaper försämras.

Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2019. p. 62
Series
TRITA-CBH-FOU ; 2019:26
Keywords
nanocellulose, nanofibril, nanofiber, CNF, nanoplatelet, nanostructure, tactoid, montmorillonite, MTM, foam, aerogel, porosity, PVA, poly(vinyl alcohol), epoxy, moisture, biocomposite, biomaterial, biobased, flame, cone calorimetry, gas barrier, coating, film.
National Category
Composite Science and Engineering Nano Technology Paper, Pulp and Fiber Technology Materials Chemistry
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-249955 (URN)978-91-7873-174-9 (ISBN)
Public defence
2019-05-22, F3, Lindstedtsvägen 26, Stockholm, 10:00 (English)
Opponent
Supervisors
Funder
Knut and Alice Wallenberg FoundationSwedish Foundation for Strategic Research , RMA11-0065
Note

QC 20190425

Available from: 2019-04-25 Created: 2019-04-23 Last updated: 2019-04-25Bibliographically approved
Andrieux, S., Medina, L., Herbst, M., Berglund, L. & Stubenrauch, C. (2019). Monodisperse highly ordered chitosan/cellulose nanocomposite foams. Composites. Part A, Applied science and manufacturing, 125, Article ID UNSP 105516.
Open this publication in new window or tab >>Monodisperse highly ordered chitosan/cellulose nanocomposite foams
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2019 (English)In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 125, article id UNSP 105516Article in journal (Refereed) Published
Abstract [en]

In solid foams, most physical properties are determined by the pore size and shape distributions and the organisation of the pores. For this reason, it is important to control the structure of porous materials. We recently tackled this issue with the help of microfluidic-aided foam templating, which allowed us to generate mono-disperse and highly ordered chitosan foams. However, the properties of foams also depend on the properties of the pore wall constituents. In case of chitosan-based foams, the foams have poor absolute mechanical properties, simply due to the fact that the solubility of chitosan in water is very low, so that the relative density of the freeze-dried foams becomes very small. Drawing inspiration from the field of nanocomposites, we incorporated cellulose nanofibres into the foamed chitosan solutions, with a view to strengthening the pore walls in the foam and thus the mechanical properties of the final foam. We report here how the cellulose nanofibres affect the structure of both the liquid foam template and the solid foam. The resulting nanocomposite foams have improved mechanical properties, which, however, are not proportional to the amount of cellulose nanofibres in the composites. One reason for this observation is the disturbance of the porous structure of the solid foams by the cellulose nanofibres.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2019
Keywords
Cellulose, Foams, Nanocomposites, Mechanical testing
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-261001 (URN)10.1016/j.compositesa.2019.105516 (DOI)000484878200005 ()2-s2.0-85068544162 (Scopus ID)
Note

QC 20191004

Available from: 2019-10-04 Created: 2019-10-04 Last updated: 2019-10-16Bibliographically approved
Medina, L., Ansari, F., Carosio, F., Salajkova, M. & Berglund, L. (2019). Nanocomposites from Clay, Cellulose Nanofibrils, and Epoxy with Improved Moisture Stability for Coatings and Semi-Structural Applications. ACS Applied Nano Materials
Open this publication in new window or tab >>Nanocomposites from Clay, Cellulose Nanofibrils, and Epoxy with Improved Moisture Stability for Coatings and Semi-Structural Applications
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2019 (English)In: ACS Applied Nano Materials, E-ISSN 2574-0970Article in journal (Refereed) Published
Abstract [en]

A new type of high reinforcement content clay-cellulose-thermoset nanocomposite was proposed, where epoxy precursors diffused into a wet porous clay-nanocellulose mat, followed by curing. The processing concept was scaled to > 200 µm thickness composites, the mechanical properties were high for nanocomposites and the materials showed better tensile properties at 90% RH compared with typical nanocellulose materials. The nanostructure and phase distributions were studied using transmission electron microscopy; Young’s modulus, yield strength, ultimate strength and ductility were determined as well as moisture sorption, fire retardancy and oxygen barrier properties. Clay and cellulose contents were varied, as well as the epoxy content. Epoxy had favorable effects on moisture stability, and also improved reinforcement effects at low reinforcement content. More homogeneous nano- and mesoscale epoxy distribution is still required for further property improvements. The materials constitute a new type of three-phase nanocomposites, of interest as coatings, films and as laminated composites for semi-structural applications.

Keywords
biocomposite, nanocellulose, mechanical, montmorillonite, fire
National Category
Composite Science and Engineering Paper, Pulp and Fiber Technology Nano Technology Materials Chemistry
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-249724 (URN)10.1021/acsanm.9b00459 (DOI)
Funder
Swedish Foundation for Strategic Research , RMA11-0065Knut and Alice Wallenberg Foundation
Note

QC 20190520

Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2019-05-20Bibliographically approved
Medina, L., Nishiyama, Y., Daicho, K., Saito, T., Yan, M. & Berglund, L. (2019). Nanostructure and Properties of Nacre-Inspired Clay/Cellulose Nanocomposites—Synchrotron X-ray Scattering Analysis. Macromolecules, 52(8), 3131-3140
Open this publication in new window or tab >>Nanostructure and Properties of Nacre-Inspired Clay/Cellulose Nanocomposites—Synchrotron X-ray Scattering Analysis
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2019 (English)In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 52, no 8, p. 3131-3140Article in journal (Refereed) Published
Abstract [en]

Nacre-inspired clay nanocomposites have excellent mechanical properties, combined with optical transmittance, gas barrier properties, and fire retardancy, but the mechanical properties are still below predictions from composite micromechanics. The properties of montmorillonite clay/nanocellulose nanocomposite hybrids are investigated as a function of clay content and show a maximum Young’s modulus as high as 28 GPa. Ultimate strength, however, decreases from 280 to 125 MPa between 0 and 80 wt % clay. Small-angle and wide-angle X-ray scattering data from synchrotron radiation are analyzed to suggest nanostructural and phase interaction factors responsible for these observations. Parameters discussed include effective platelet modulus, platelet out-of-plane orientation distribution, nanoporosity, and platelet agglomeration state.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Composite Science and Engineering Paper, Pulp and Fiber Technology Nano Technology
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-249608 (URN)10.1021/acs.macromol.9b00333 (DOI)000466053200022 ()
Funder
Knut and Alice Wallenberg FoundationSwedish Foundation for Strategic Research , RMA11-0065
Note

QC 20190521

Available from: 2019-04-12 Created: 2019-04-12 Last updated: 2019-10-24Bibliographically approved
Medina, L., Carosio, F. & Berglund, L. (2019). Recyclable nanocomposite foams of Poly(vinyl alcohol), clay and cellulose nanofibrils - Mechanical properties and flame retardancy. Composites Science And Technology, 182, Article ID 107762.
Open this publication in new window or tab >>Recyclable nanocomposite foams of Poly(vinyl alcohol), clay and cellulose nanofibrils - Mechanical properties and flame retardancy
2019 (English)In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 182, article id 107762Article in journal (Refereed) Published
Abstract [en]

Foam-like clay-nanocellulose hybrids are of great interest as load-bearing structural foams with excellent fire retardancy, due to unique effects from clay on thermal cellulose degradation. For the first time, the fire retardancy of clay-nanocellulose foams are studied in detail, in particular the effect of a third polymer phase, poly(vinyl alcohol). The composition with optimum mechanical properties and fire retardancy is identified and analyzed. Foams are prepared by freeze-drying and the compositions are varied systematically. Thermogravimetric analysis is performed on foam degradation. Mechanical properties from compression tests and fire retardancy data from cone calorimetry are reported, together with cellular structures from SEM and relative density estimates for the foams. Self-extinguishing foams are obtained with superior flame retardancy to commercial polymer foams. Addition of poly(vinyl alcohol) is beneficial for mechanical properties of clay-nanocellulose foams, but impedes the fire retardancy by reducing clay-cellulose synergies and cellulose charring during degradation.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2019
Keywords
Montmorillonite, Fire retardancy, Aerogels, Biocomposites, Freeze-drying
National Category
Bio Materials
Identifiers
urn:nbn:se:kth:diva-263365 (URN)10.1016/j.compscitech.2019.107762 (DOI)000487564800053 ()
Note

QC 20191118

Available from: 2019-11-18 Created: 2019-11-18 Last updated: 2019-11-18Bibliographically approved
Medina, L. & Berglund, L. (2018). Brick-and-mortar biocomposites from cellulose nanofibrils and clay nanoplatelets. 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. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>Brick-and-mortar biocomposites from cellulose nanofibrils and clay nanoplatelets
2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-232280 (URN)000435539906237 ()
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 20180719

Available from: 2018-07-19 Created: 2018-07-19 Last updated: 2018-07-19Bibliographically approved
Castro, D. O., Karim, Z., Medina, L., Häggström, J.-O. -., Carosio, F., Svedberg, A., . . . Berglund, L. A. (2018). The use of a pilot-scale continuous paper process for fire retardant cellulose-kaolinite nanocomposites. Composites Science And Technology, 162, 215-224
Open this publication in new window or tab >>The use of a pilot-scale continuous paper process for fire retardant cellulose-kaolinite nanocomposites
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2018 (English)In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 162, p. 215-224Article in journal (Refereed) Published
Abstract [en]

Nanostructured materials are difficult to prepare rapidly and at large scale. Melt-processed polymer-clay nanocomposites are an exception, but the clay content is typically below 5 wt%. An approach for manufacturing of microfibrillated cellulose (MFC)/kaolinite nanocomposites is here demonstrated in pilot-scale by continuous production of hybrid nanopaper structures with thickness of around 100 μm. The colloidal nature of MFC suspensions disintegrated from chemical wood fiber pulp offers the possibility to add kaolinite clay platelet particles of nanoscale thickness. For initial lab scale optimization purposes, nanocomposite processing (dewatering, small particle retention etc) and characterization (mechanical properties, density etc) were investigated using a sheet former (Rapid Köthen). This was followed by a continuous fabrication of composite paper structures using a pilot-scale web former. Nanocomposite morphology was assessed by scanning electron microscopy (SEM). Mechanical properties were measured in uniaxial tension. The fire retardancy was evaluated by cone calorimetry. Inorganic hybrid composites with high content of in-plane oriented nanocellulose, nanoclay and wood fibers were successfully produced at pilot scale. Potential applications include fire retardant paperboard for semi structural applications.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Biocomposite, Hybrid, Mechanical properties, Microfibrillated cellulose, Nanocellulose
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-228719 (URN)10.1016/j.compscitech.2018.04.032 (DOI)2-s2.0-85046634249 (Scopus ID)
Note

QC 20180530

Available from: 2018-05-30 Created: 2018-05-30 Last updated: 2018-05-30Bibliographically approved
Ansari, F., Berglund, L. & Medina, L. (2017). Epoxies can solve moisture problems in nanocellulose materials. In: International Conference on Nanotechnology for Renewable Materials 2017: . Paper presented at TAPPI International Conference on Nanotechnology for Renewable Materials 2017, 5 June 2017 through 8 June 2017 (pp. 1220-1227). TAPPI Press
Open this publication in new window or tab >>Epoxies can solve moisture problems in nanocellulose materials
2017 (English)In: International Conference on Nanotechnology for Renewable Materials 2017, TAPPI Press , 2017, p. 1220-1227Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
TAPPI Press, 2017
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-236825 (URN)2-s2.0-85048401444 (Scopus ID)9781510850897 (ISBN)
Conference
TAPPI International Conference on Nanotechnology for Renewable Materials 2017, 5 June 2017 through 8 June 2017
Note

QC 20181221

Available from: 2018-12-21 Created: 2018-12-21 Last updated: 2018-12-21Bibliographically approved
Fu, Q., Medina, L., Li, Y., Carosio, F., Hajian, A. & Berglund, L. A. (2017). Nanostructured Wood Hybrids for Fire-Retardancy Prepared by Clay Impregnation into the Cell Wall. ACS Applied Materials and Interfaces, 9(41), 36154-36163
Open this publication in new window or tab >>Nanostructured Wood Hybrids for Fire-Retardancy Prepared by Clay Impregnation into the Cell Wall
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2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 41, p. 36154-36163Article in journal (Refereed) Published
Abstract [en]

Eco-friendly materials need "green" fire-retardancy treatments, which offer opportunity for new wood nanotechnologies. Balsa wood (Ochroma pyramidale) was delignified to form a hierarchically structured and nanoporous scaffold mainly composed of cellulose nanofibrils. This nanocellulosic wood scaffold was impregnated with colloidal montmorillonite clay to form a nanostructured wood hybrid with high flame-retardancy. The nanoporous scaffold was characterized by scanning electron microscopy and gas adsorption. Flame-retardancy was evaluated by cone calorimetry, whereas thermal and thermo-oxidative stabilities were assessed by thermogravimetry. The location of well-distributed clay nanoplatelets inside the cell walls was confirmed by energy-dispersive X-ray analysis. This unique nanostructure dramatically increased the thermal stability because of thermal insulation, oxygen depletion, and catalytic charring effects. A coherent organic/inorganic charred residue was formed during combustion, leading to a strongly reduced heat release rate peak and reduced smoke generation.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
Keywords
biocomposite, nanocomposite, layered silicate, nanocellulose, nanostructured, inorganic hybrid, wood nanotechnology
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-217436 (URN)10.1021/acsami.7b10008 (DOI)000413503700067 ()28825295 (PubMedID)2-s2.0-85031677298 (Scopus ID)
Note

QC 20171117

Available from: 2017-11-17 Created: 2017-11-17 Last updated: 2018-02-21Bibliographically approved
Oliveira de Castro, D., Karim, Z., Medina, L., Svedberg, A., Wågberg, L., Söderberg, D. & Berglund, L. (2017). Scale up of nanocellulose/hybrid inorganic films using a pilot web former. In: International Conference on Nanotechnology for Renewable Materials 2017: . Paper presented at TAPPI International Conference on Nanotechnology for Renewable Materials 2017, 5 June 2017 through 8 June 2017 (pp. 408-418). TAPPI Press
Open this publication in new window or tab >>Scale up of nanocellulose/hybrid inorganic films using a pilot web former
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2017 (English)In: International Conference on Nanotechnology for Renewable Materials 2017, TAPPI Press , 2017, p. 408-418Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
TAPPI Press, 2017
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-236834 (URN)2-s2.0-85048363099 (Scopus ID)9781510850897 (ISBN)
Conference
TAPPI International Conference on Nanotechnology for Renewable Materials 2017, 5 June 2017 through 8 June 2017
Note

QC 20181221

Available from: 2018-12-21 Created: 2018-12-21 Last updated: 2018-12-21Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8547-9046

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