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  • 1.
    Bridarolli, Alexandra
    et al.
    UCL Eastman Dental Institute, United Kingdom.
    Odlyha, Marianne
    Birkbeck College, United Kingdom.
    Nechyporchuk, Oleksandr
    RISE - Research Institutes of Sweden, Materials and Production, IVF. Chalmers University of Technology, Sweden.
    Holmberg, Krister
    Chalmers University of Technology, Sweden.
    Ruiz-Recasens, Cristina
    University of Barcelona, Spain.
    Bordes, Romain
    Chalmers University of Technology, Sweden.
    Bozec, L.
    UCL Eastman Dental Institute, United Kingdom; University of Toronto, Canada.
    Evaluation of the Adhesion and Performance of Natural Consolidants for Cotton Canvas Conservation2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 39, p. 33652-33661Article in journal (Refereed)
    Abstract [en]

    Recent developments in paper and canvas conservation have seen the introduction of nanocellulose (NC) as a compatible treatment for the consolidation of historical cellulosic artifacts and manuscripts. However, as part of the assessment of these new materials for canvas consolidation, the adhesion of the consolidation treatment (which takes place between the applied material and the substrate) has not yet been evaluated, and as a result, it is poorly understood by both the scientific and conservation communities. After evaluating the potential of NC treatments for the consolidation of cotton painting canvas, we investigate a route to promote the interaction between the existing canvas and the nanocellulose treatment, which is in our case made of cellulose nanofibrils (CNF). This was carried out by introducing a cationic polymer, polyamidoamine-epichlorohydrin (PAAE), as an intermediate layer between the canvas and the CNF. The morphological, chemical, and mechanical evaluation of the canvas samples at different relative humidity (RH) levels demonstrated how the adhesion of the added PAAE layer is a dominant factor in the consolidation process. Improvement in the coating of canvas single fibers by the CNF, higher adhesion energy between the canvas fibers and the CNF treatment, and finally overall stronger canvas reinforcement were observed following the introduction of PAAE. However, an increase in mechanical response to moisture sorption and desorption was also observed for the PAAE-treated canvases. Overall, this study shows the complexity of such systems and, as such, the relevance of using a multiscale approach for their assessment.

  • 2.
    Kolman, Krzysztof
    et al.
    Chalmers University of Technology, Sweden.
    Nechyporchuk, Oleksandr
    RISE - Research Institutes of Sweden, Materials and Production, IVF. Chalmers University of Technology, Sweden.
    Persson, Michael
    Chalmers University of Technology, Sweden; AkzoNobel Pulp and Performance Chemicals, Sweden .
    Holmberg, Krister
    Chalmers University of Technology, Sweden.
    Bordes, Romain
    Chalmers University of Technology, Sweden.
    Preparation of silica/polyelectrolyte complexes for textile strengthening applied to painting canvas restoration2017In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 09277757, Vol. 532, p. 420-427Article in journal (Refereed)
    Abstract [en]

    We here report three different approaches to prepare silica-polyelectrolyte complexes for mechanical strengthening of cotton fibers. In the first approach, polyvinylpyrrolidone (PVP) was used as a stabilizing polymer to delay the adsorption of a poly(quaternary ammonium) species, PQA (a copolymer of dimethylamine and epichlorohydrin), on the surface of silica. In the second approach cationic starch (CS), which is a branched polyelectrolyte, was used and the adsorption of CS resulted in formulations with good colloidal stability. The third approach was based on reduction of the charge density of silica to prevent PQA adsorption. Lowering the pH reduced the surface charge of the silica and enabled control of the adsorption. As a result, the aggregation was prevented and only a thin layer of polymer adsorbed. For all formulations a second polyelectrolyte, carboxymethyl cellulose (CMC) was subsequently adsorbed on the cationic polyelectrolyte layer. The silica/polyelectrolyte formulations were evaluated by dynamic light scattering (DLS). The obtained formulations were applied on model surfaces of degraded painting canvas. The performance of the silica particles coated either with one cationic polyelectrolyte and or with a layer of cationic polyelectrolyte followed by a layer of anionic polyelectrolyte were assessed by tensile testing and the morphology of the treated samples was investigated with SEM. The particles coated with a single cationic layer increased the maximum load at break by 29% at the cost of a reduction in strain. The particles coated with a double layer increased the maximum load to a lesser extent; however, higher values of strain were recorded. For all systems the mass uptake was limited to around 5 wt%.

  • 3.
    Nechyporchuk, Oleksandr
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Bordes, Romain
    Chalmers University of Technology, Sweden.
    Köhnke, Tobias
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Wet Spinning of Flame-Retardant Cellulosic Fibers Supported by Interfacial Complexation of Cellulose Nanofibrils with Silica Nanoparticles2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 44, p. 39069-39077Article in journal (Refereed)
    Abstract [en]

    The inherent flammability of cellulosic fibers limits their use in some advanced applications. This work demonstrates for the first time the production of flame-retardant macroscopic fibers from wood-derived cellulose nanofibrils (CNF) and silica nanoparticles (SNP). The fibers are made by extrusion of aqueous suspensions of anionic CNF into a coagulation bath of cationic SNP at an acidic pH. As a result, the fibers with a CNF core and a SNP thin shell are produced through interfacial complexation. Silica-modified nanocellulose fibers with a diameter of ca. 15 μm, a titer of ca. 3 dtex and a tenacity of ca. 13 cN tex–1 are shown. The flame retardancy of the fibers is demonstrated, which is attributed to the capacity of SNP to promote char forming and heat insulation on the fiber surface.

  • 4.
    Nechyporchuk, Oleksandr
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Håkansson, Karl
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Gowda.V, Krishne
    KTH Royal Institute of Technology, Sweden.
    Lundell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Hagström, Bengt
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Köhnke, Tobias
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Continuous Assembly of Cellulose Nanofibrils and Nanocrystals into Strong Macrofibers through Microfluidic Spinning2018In: Advanced Materials Technologies, ISSN 2365-709X, article id 1800557Article in journal (Refereed)
    Abstract [en]

    Microfluidic fiber spinning is a promising technique for assembling cellulose nanomaterials into macroscopic fibers. However, its implementation requires upscalabe fabrication processes while maintaining high strength of the fibers, which could not be previously achieved. Herein, a continuous wet spinning process based on microfluidic flow focusing is developed to produce strong fibers from cellulose nanofibrils (CNFs) and nanocrystals (CNCs). Fibers with an average breaking tenacity as high as 29.5 cN tex−1 and Young's modulus of 1146 cN tex−1 are reported for the first time, produced from nonhighly purified CNF grades. Using the same developed method, wet spinning of fibers from CNCs is achieved for the first time, reaching an average Young's modulus of 1263 cN tex−1 and a breaking tenacity of 10.6 cN tex−1, thus exhibiting strength twice as high as that of common CNC films. A rather similar stiffness of CNC and CNF spun fibers may originate from similar degrees of alignment, as confirmed by wide-angle X-ray scattering (WAXS) and birefringence measurements, whereas lower strength may primarily arise from the shorter length of CNCs compared to that of CNFs. The benefit of CNCs is their higher solids content in the dopes. By combining both CNCs and CNFs, the fiber properties can be tuned.

  • 5.
    Nechyporchuk, Oleksandr
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF. Chalmers University of Technology, Sweden.
    Kolman, Krzysztof
    Chalmers University of Technology, Sweden; University of Gothenburg, Sweden.
    Bridarolli, Alexandra
    University of London, UK .
    Odlyha, Marianne
    University of London, UK.
    Bozec, L.
    University of London, UK.
    Oriola, Marta
    University of Barcelona, Spain.
    Campo-Francés, Gema
    University of Barcelona, Spain.
    Persson, Michael E
    AkzoNobel, Sweden.
    Holmberg, Krister
    Chalmers University of Technology, Sweden.
    Bordes, Romain
    Chalmers University of Technology, Sweden.
    On the potential of using nanocellulose for consolidation of painting canvases2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 194, p. 161-169Article in journal (Refereed)
    Abstract [en]

    Nanocellulose has been recently proposed as a novel consolidant for historical papers. Its use for painting canvas consolidation, however, remains unexplored. Here, we show for the first time how different nanocelluloses, namely mechanically isolated cellulose nanofibrils (CNF), carboxymethylated cellulose nanofibrils (CCNF) and cellulose nanocrystals (CNC), act as a bio-based alternative to synthetic resins and other conventional canvas consolidants. Importantly, we demonstrate that compared to some traditional consolidants, all tested nanocelluloses provided reinforcement in the adequate elongation regime. CCNF showed the best consolidation per added weight; however, it had to be handled at very low solids content compared to other nanocelluloses, exposing canvases to larger water volumes. CNC reinforced the least per added weight but could be used in more concentrated suspensions, giving the strongest consolidation after an equivalent number of coatings. CNF performed between CNC and CCNF. All nanocelluloses showed better consolidation than lining with synthetic adhesive (Beva 371) and linen canvas in the elongation region of interest. 

  • 6.
    Nechyporchuk, Oleksandr
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Köhnke, Tobias
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Regenerated Casein-Nanocellulose Composite Fibers via Wet Spinning2019In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 7, no 1, p. 1419-1426Article in journal (Refereed)
    Abstract [en]

    Development of sustainable biobased fibers is required to displace their fossil-based counterparts, e.g., in textile, nonwoven, or composite applications. Regenerated protein fibers have a potential in this regard if their mechanical properties are improved. Herein, we study for the first time the use of nanocellulose as reinforcement in regenerated protein fibers produced using wet spinning. The influence of cellulose nanocrystals (CNC) incorporated into regenerated casein fibers is examined in terms of mechanical and morphological properties. The influence of different conditions for fiber chemical cross-linking is also investigated. Incorporation of CNC (up to 37.5 wt %) into spin dopes results in a continuous increase of fiber Young's modulus (up to twofold) in the dry state. Both maximum and breaking tenacity of dry fibers are enhanced by CNC, with a maximum at 7.0-10.5 wt % of CNC. When testing after being wetted, both breaking tenacity and Young's modulus of the composite fibers decrease, likely due to weakening of hydrogen bonds between CNC in the presence of water. We also demonstrate that the presence of salt during chemical cross-linking is crucial to produce intact and separated fibers in the yarn.

1 - 6 of 6
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