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Publikationer (10 of 27) Visa alla publikationer
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
Öppna denna publikation i ny flik eller fönster >>Nanocomposites from Clay, Cellulose Nanofibrils, and Epoxy with Improved Moisture Stability for Coatings and Semi-Structural Applications
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2019 (Engelska)Ingår i: ACS Applied Nano Materials, E-ISSN 2574-0970Artikel i tidskrift (Refereegranskat) 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.

Nyckelord
biocomposite, nanocellulose, mechanical, montmorillonite, fire
Nationell ämneskategori
Kompositmaterial och -teknik Pappers-, massa- och fiberteknik Nanoteknik Materialkemi
Forskningsämne
Fiber- och polymervetenskap
Identifikatorer
urn:nbn:se:kth:diva-249724 (URN)10.1021/acsanm.9b00459 (DOI)
Forskningsfinansiär
Stiftelsen för strategisk forskning (SSF), RMA11-0065Knut och Alice Wallenbergs Stiftelse
Anmärkning

QC 20190520

Tillgänglig från: 2019-04-18 Skapad: 2019-04-18 Senast uppdaterad: 2019-05-20Bibliografiskt granskad
Kupka, V., Zhou, Q., Ansari, F., Tang, H., Slouf, M., Vojtova, L., . . . Jancar, J. (2019). Well-dispersed polyurethane/cellulose nanocrystal nanocomposites synthesized by a solvent-free procedure in bulk. Polymer Composites, 40, E456-E465
Öppna denna publikation i ny flik eller fönster >>Well-dispersed polyurethane/cellulose nanocrystal nanocomposites synthesized by a solvent-free procedure in bulk
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2019 (Engelska)Ingår i: Polymer Composites, ISSN 0272-8397, E-ISSN 1548-0569, Vol. 40, s. E456-E465Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Polyurethane (PU) nanocomposites utilizing cellulose nanocrystals (CNCs) as nanofiller and amorphous PU matrix were synthesized in a novel solvent-free bulk process. A green nanofiller, CNCs, was studied as reinforcement and was further modified by grafting poly(ethylene glycol) (PEG) on the CNC surface (CNC-PEG). Transmission electron microscopy revealed an excellent dispersion of the PEGylated CNC nanoparticles in the PU matrix, whereas as-received CNCs formed agglomerates. The results indicated strong improvements in tensile properties with Young's modulus increasing up to 50% and strength up to 25% for both, PU/CNC and PU/CNC-PEG nanocomposites. The enhanced tensile modulus was attributed to stiff particle reinforcement together with an increase in glass transition temperature.

Ort, förlag, år, upplaga, sidor
WILEY, 2019
Nationell ämneskategori
Polymerkemi
Identifikatorer
urn:nbn:se:kth:diva-246291 (URN)10.1002/pc.24748 (DOI)000459570800043 ()2-s2.0-85041194513 (Scopus ID)
Anmärkning

QC 20190325

Tillgänglig från: 2019-03-25 Skapad: 2019-03-25 Senast uppdaterad: 2019-03-25Bibliografiskt granskad
Mittal, N., Ansari, F., Gowda, K. V., Brouzet, C., Chen, P., Larsson, P. T., . . . Söderberg, D. (2018). Multiscale Control of Nanocellulose Assembly: Transferring Remarkable Nanoscale Fibril Mechanics to Macroscale Fibers. ACS Nano, 12(7), 6378-6388
Öppna denna publikation i ny flik eller fönster >>Multiscale Control of Nanocellulose Assembly: Transferring Remarkable Nanoscale Fibril Mechanics to Macroscale Fibers
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2018 (Engelska)Ingår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, nr 7, s. 6378-6388Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Nanoscale building blocks of many materials exhibit extraordinary mechanical properties due to their defect-free molecular structure. Translation of these high mechanical properties to macroscopic materials represents a difficult materials engineering challenge due to the necessity to organize these building blocks into multiscale patterns and mitigate defects emerging at larger scales. Cellulose nanofibrils (CNFs), the most abundant structural element in living systems, has impressively high strength and stiffness, but natural or artificial cellulose composites are 3-15 times weaker than the CNFs. Here, we report the flow-assisted organization of CNFs into macroscale fibers with nearly perfect unidirectional alignment. Efficient stress transfer from macroscale to individual CNF due to cross-linking and high degree of order enables their Young's modulus to reach up to 86 GPa and a tensile strength of 1.57 GPa, exceeding the mechanical properties of known natural or synthetic biopolymeric materials. The specific strength of our CNF fibers engineered at multiscale also exceeds that of metals, alloys, and glass fibers, enhancing the potential of sustainable lightweight high-performance materials with multiscale self-organization.

Ort, förlag, år, upplaga, sidor
American Chemical Society (ACS), 2018
Nyckelord
bio-based materials, selforganization, mechanical properties, microfluidics, cellulose nanofibrils, nanocompositesbio-based materials, selforganization, mechanical properties, microfluidics, cellulose nanofibrils, nanocomposites
Nationell ämneskategori
Teknik och teknologier
Forskningsämne
Teknisk mekanik; Fiber- och polymervetenskap; Fysik
Identifikatorer
urn:nbn:se:kth:diva-229288 (URN)10.1021/acsnano.8b01084 (DOI)000440505000004 ()29741364 (PubMedID)2-s2.0-85049865626 (Scopus ID)
Forskningsfinansiär
Knut och Alice Wallenbergs Stiftelse
Anmärkning

QC 20180608

Tillgänglig från: 2018-06-01 Skapad: 2018-06-01 Senast uppdaterad: 2019-02-07Bibliografiskt granskad
Zhao, M., Ansari, F., Takeuchi, M., Shimizu, M., Saito, T., Berglund, L. A. & Isogai, A. (2018). Nematic structuring of transparent and multifunctional nanocellulose papers. Nanoscale Horizons, 3(1), 28-34
Öppna denna publikation i ny flik eller fönster >>Nematic structuring of transparent and multifunctional nanocellulose papers
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2018 (Engelska)Ingår i: Nanoscale Horizons, ISSN 2055-6756, Vol. 3, nr 1, s. 28-34Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The nematic structuring of cellulose nanofibers (CNFs) is proposed as a nanostructural engineering tool for exploiting the potential of CNFs in conceptually new "transparent papers". The nematic-structured CNF papers exhibit superior mechanical properties, optical transparency, gas-barrier properties, heat transfer properties and electrical resistivity, compared with conventional randomly-structured CNF papers.

Ort, förlag, år, upplaga, sidor
Royal Society of Chemistry, 2018
Nationell ämneskategori
Nanoteknik
Identifikatorer
urn:nbn:se:kth:diva-223205 (URN)10.1039/c7nh00104e (DOI)000418196800002 ()2-s2.0-85038940009 (Scopus ID)
Anmärkning

Export Date: 13 February 2018; Article; Correspondence Address: Saito, T.; Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, University of TokyoJapan; email: asaitot@mail.ecc.u-tokyo.ac.jp; Funding details: JST, Japan Science and Technology Agency; Funding details: 15H04524, JSPS, Japan Society for the Promotion of Science; Funding details: 15K14765, JSPS, Japan Society for the Promotion of Science; Funding details: JPMJCR13B2, CREST, Core Research for Evolutional Science and Technology. QC 20180227

Tillgänglig från: 2018-02-27 Skapad: 2018-02-27 Senast uppdaterad: 2018-02-27Bibliografiskt granskad
Ansari, F. & Berglund, L. A. (2018). Toward Semistructural Cellulose Nanocomposites: The Need for Scalable Processing and Interface Tailoring. Biomacromolecules, 19(7), 2341-2350
Öppna denna publikation i ny flik eller fönster >>Toward Semistructural Cellulose Nanocomposites: The Need for Scalable Processing and Interface Tailoring
2018 (Engelska)Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, nr 7, s. 2341-2350Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Cellulose nanocomposites can be considered for semistructural load-bearing applications where modulus and strength requirements exceed 10 GPa and 100 MPa, respectively. Such properties are higher than for most neat polymers but typical for molded short glass fiber composites. The research challenge for polymer matrix biocomposites is to develop processing concepts that allow high cellulose nanofibril (CNF) content, nanostructural control in the form of well-dispersed CNF, the use of suitable polymer matrices, as well as molecular scale interface tailoring to address moisture effects. From a practical point of view, the processing concept needs to be scalable so that large-scale industrial processing is feasible. The vast majority of cellulose nanocomposite studies elaborate on materials with low nanocellulose content. An important reason is the challenge to prevent CNF agglomeration at high CNF content. Research activities are therefore needed on concepts with the potential for rapid processing with controlled nanostructure, including well-dispersed fibrils at high CNF content so that favorable properties are obtained. This perspective discusses processing strategies, agglomeration problems, opportunities, and effects from interface tailoring. Specifically, preformed CNF mats can be used to design nanostructured biocomposites with high CNF content. Because very few composite materials combine functional and structural properties, CNF materials are an exception in this sense. The suggested processing concept could include functional components (inorganic clays, carbon nanotubes, magnetic nanoparticles, among others). In functional three-phase systems, CNF networks are combined with functional components (nanoparticles or fibril coatings) together with a ductile polymer matrix. Such materials can have functional properties (optical, magnetic, electric, etc.) in combination with mechanical performance, and the comparably low cost of nanocellulose may facilitate the use of large nanocomposite structures in industrial applications.

Ort, förlag, år, upplaga, sidor
American Chemical Society (ACS), 2018
Nationell ämneskategori
Biokemi och molekylärbiologi
Identifikatorer
urn:nbn:se:kth:diva-232786 (URN)10.1021/acs.biomac.8b00142 (DOI)000438470800001 ()29577729 (PubMedID)2-s2.0-85049103756 (Scopus ID)
Forskningsfinansiär
Stiftelsen för strategisk forskning (SSF), GMT14-0036Knut och Alice Wallenbergs Stiftelse
Anmärkning

QC 20180806

Tillgänglig från: 2018-08-06 Skapad: 2018-08-06 Senast uppdaterad: 2018-08-06Bibliografiskt granskad
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
Öppna denna publikation i ny flik eller fönster >>Epoxies can solve moisture problems in nanocellulose materials
2017 (Engelska)Ingår i: International Conference on Nanotechnology for Renewable Materials 2017, TAPPI Press , 2017, s. 1220-1227Konferensbidrag, Publicerat paper (Refereegranskat)
Ort, förlag, år, upplaga, sidor
TAPPI Press, 2017
Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:kth:diva-236825 (URN)2-s2.0-85048401444 (Scopus ID)9781510850897 (ISBN)
Konferens
TAPPI International Conference on Nanotechnology for Renewable Materials 2017, 5 June 2017 through 8 June 2017
Anmärkning

QC 20181221

Tillgänglig från: 2018-12-21 Skapad: 2018-12-21 Senast uppdaterad: 2018-12-21Bibliografiskt granskad
Ansari, F., Granda, L. A., Joffe, R., Berglund, L. & Vilaseca, F. (2017). Experimental evaluation of anisotropy in injection molded polypropylene/wood fiber biocomposites. Composites. Part A, Applied science and manufacturing, 96, 147-154
Öppna denna publikation i ny flik eller fönster >>Experimental evaluation of anisotropy in injection molded polypropylene/wood fiber biocomposites
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2017 (Engelska)Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 96, s. 147-154Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Although the anisotropy of wood fibers is reasonably well established, the anisotropy of injection molded wood fiber composites is not well understood. This work focuses on chemo-thermomechanical pulp (CTMP) reinforced polypropylene (PP) composites. A kinetic mixer (Gelimat) is used for compounding CTMP/PP composites, followed by injection molding. Effects from processing induced orientation on mechanical properties are investigated. For this purpose, a film gate mold was designed to inject composites in the shape of plates so that specimens in different directions to the flow could be evaluated. Observations from tensile tests were complemented by performing flexural tests (in different directions) on discs cut from the injected plates. SEM was used to qualitatively observe the fiber orientation in the composites. At high fiber content, both modulus and tensile strength could differ by as much as 40% along the flow and transverse to the flow. The fiber orientation was strongly increased at the highest fiber content, as concluded from theoretical analysis.

Ort, förlag, år, upplaga, sidor
Elsevier, 2017
Nyckelord
A. Wood, C. Anisotropy, CTMP orientation, E. Injection molding, Melt processing, Anisotropy, Fibers, Molding, Polypropylenes, Reinforced plastics, Tensile strength, Tensile testing, Thermomechanical pulp, Wood, Wood products, Bio-composites, E. Injection moldings, Experimental evaluation, Fiber contents, Flexural tests, Induced orientation, Wood-fiber composites, Injection molding
Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:kth:diva-207326 (URN)10.1016/j.compositesa.2017.02.003 (DOI)000399850600016 ()2-s2.0-85014372994 (Scopus ID)
Anmärkning

QC 20170607

Tillgänglig från: 2017-06-07 Skapad: 2017-06-07 Senast uppdaterad: 2017-11-10Bibliografiskt granskad
Ansari, F., Rojas Escontrillas, R. & Berglund, L. (2017). Molecular blending and reinforcing effect of lignin in ductile epoxy resins. Paper presented at 253rd National Meeting of the American-Chemical-Society (ACS) on Advanced Materials, Technologies, Systems, and Processes, APR 02-06, 2017, San Francisco, CA. Abstract of Papers of the American Chemical Society, 253
Öppna denna publikation i ny flik eller fönster >>Molecular blending and reinforcing effect of lignin in ductile epoxy resins
2017 (Engelska)Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Artikel i tidskrift, Meeting abstract (Övrigt vetenskapligt) Published
Ort, förlag, år, upplaga, sidor
American Chemical Society (ACS), 2017
Nationell ämneskategori
Kemi
Identifikatorer
urn:nbn:se:kth:diva-243594 (URN)000430568503128 ()
Konferens
253rd National Meeting of the American-Chemical-Society (ACS) on Advanced Materials, Technologies, Systems, and Processes, APR 02-06, 2017, San Francisco, CA
Anmärkning

QC 20190206

Tillgänglig från: 2019-02-06 Skapad: 2019-02-06 Senast uppdaterad: 2019-02-06Bibliografiskt granskad
Ansari, F. (2016). Cellulose fibers reinforced thermoset composites - micro vs nano. Abstract of Papers of the American Chemical Society, 251
Öppna denna publikation i ny flik eller fönster >>Cellulose fibers reinforced thermoset composites - micro vs nano
2016 (Engelska)Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Artikel i tidskrift, Meeting abstract (Övrigt vetenskapligt) Published
Ort, förlag, år, upplaga, sidor
AMER CHEMICAL SOC, 2016
Nationell ämneskategori
Organisk kemi
Identifikatorer
urn:nbn:se:kth:diva-242666 (URN)000431903802571 ()
Anmärkning

QC 20190222

Tillgänglig från: 2019-02-22 Skapad: 2019-02-22 Senast uppdaterad: 2019-02-22Bibliografiskt granskad
Ansari, F., Lindh, E. L., Furo, I., Johansson, M. K. .. & Berglund, L. A. (2016). Interface tailoring through covalent hydroxyl-epoxy bonds improves hygromechanical stability in nanocellulose materials. Composites Science And Technology, 134, 175-183
Öppna denna publikation i ny flik eller fönster >>Interface tailoring through covalent hydroxyl-epoxy bonds improves hygromechanical stability in nanocellulose materials
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2016 (Engelska)Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 134, s. 175-183Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Wide-spread use of cellulose nanofibril (CNF) biocomposites and nanomaterials is limited by CNF moisture sensitivity due to surface hydration. We report on a versatile and scalable interface tailoring route for CNF to address this, based on technically important epoxide chemistry. Bulk impregnation of epoxide-amine containing liquids is used to show that CNF hydroxyls can react with epoxides at high rates and high degree of conversion to form covalent bonds. Reactions take place inside nanostructured CNF networks under benign conditions, and are verified by solid state NMR. Epoxide modified CNF nanopaper shows significantly improved mechanical properties under moist and wet conditions. High resolution microscopy is used in fractography studies to relate the property differences to structural change. The cellulose-epoxide interface tailoring concept is versatile in that the functionality of molecules with epoxide end-groups can be varied over a wide range. Furthermore, epoxide reactions with nanocellulose can be readily implemented for processing of moisture-stable, tailored interface biocomposites in the form of coatings, adhesives and molded composites.

Nyckelord
Nano composites, Wood, Nanopaper, Biocomposites, Interphase
Nationell ämneskategori
Pappers-, massa- och fiberteknik
Identifikatorer
urn:nbn:se:kth:diva-192103 (URN)10.1016/j.compscitech.2016.08.002 (DOI)000384868500020 ()2-s2.0-84983683523 (Scopus ID)
Anmärkning

QC 20160906

Tillgänglig från: 2016-09-05 Skapad: 2016-09-05 Senast uppdaterad: 2017-11-21Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0001-7870-6327

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