On the origins of the elasticity of cellulose nanofiber nanocomposites and nanopapers: a micromechanical approach

Martoïa, F.; Dumont, Pierre; Orgéas, Laurent; Belgacem, Mohamed Naceur; Putaux, Jean‐Luc

doi:10.1039/c6ra07176g

Cited by 22 publications

(9 citation statements)

References 86 publications

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“…Upon bending, the crystal developed a sharp kink identical to that observed experimentally for processed celluloses (Kekaelaeinen et al 2012;Wang et al 2012;Zeng et al 2012;Martoia et al 2016). We found shear deformations are very important when the bending load is applied on the hydrophobic face, for which the bending rigidity is also the lowest.…”

Section: Introductionsupporting

confidence: 55%

Iα to Iβ mechano-conversion and amorphization in native cellulose simulated by crystal bending

et al. 2018

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The bending of rod-like native cellulose crystals with degree of polymerization 40 and 160 using molecular dynamics simulations resulted in a deformation-induced local amorphization at the kinking point and allomorphic interconversion between cellulose Ia and Ib in the unbent segments. The transformation mechanism involves a longitudinal chain slippage of the hydrogen-bonded sheets by the length of one anhydroglucose residue (* 0.5 nm), which alters the chain stacking from the monotonic (Ia) form to the alternating Ib one or vice versa. This mechanical deformation converts the Ia form progressively to the Ib form, as has been experimentally observed for ultrasonication of microfibrils. Ib is also able to partially convert to Ia-like organization but this conversion is only transitory. The qualitative agreement between the behavior of ultrasonicated microfibrils and in silico observed Ia ? Ib conversion suggests that shear deformation and chain slippage under bending deformation is a general process when cellulose fibrils experience lateral mechanical stress.

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Section: Introductionsupporting

confidence: 55%

Iα to Iβ mechano-conversion and amorphization in native cellulose simulated by crystal bending

et al. 2018

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“…Using volume excluded concepts, the authors showed that C* probably corresponded to a percolation threshold below which nanocellulose networks were no longer connected and lost their mechanical integrity. The percolation threshold that corresponds to a critical number of bonds or interactions per nanofibre z * , was estimated using the statistical tube model for fibrous networks of homogeneously distributed straight fibres [150][151][152]:…”

Section: Nanofibre Slendernessmentioning

confidence: 99%

Ice-Templated Porous Nanocellulose-Based Materials: Current Progress and Opportunities for Materials Engineering

et al. 2018

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Nanocelluloses (cellulose nanocrystals, CNCs, or cellulose nanofibrils, CNFs) are the elementary reinforcing constituents of plant cell walls. Because of their pronounced slenderness and outstanding intrinsic mechanical properties, nanocelluloses constitute promising building blocks for the design of future biobased high-performance materials such as nanocomposites, dense and transparent films, continuous filaments, and aerogels and foams. The research interest in nanocellulose-based aerogels and foams is recent but growing rapidly. These materials have great potential in many engineering fields, including construction, transportation, energy, and biomedical sectors. Among the various processing routes used to obtain these materials, ice-templating is one of the most regarded, owing to its simplicity and versatility and the wide variety of porous materials that this technique can provide. The focus of this review is to discuss the current state of the art and understanding of ice-templated porous nanocellulose-based materials. We provide a review of the main forming processes that use the principle of ice-templating to produce porous nanocellulose-based materials and discuss the effect of processing conditions and suspension formulation on the resulting microstructures of the materials.

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“…Vast research efforts are currently underway worldwide to extract from biomass slender crystalline cellulose nanoparticles (CNs) ( 2 ), i.e., portions of microfibrils. CNs are used as building blocks for novel engineered materials, such as nanocomposites ( 2 , 3 , 5 ), densely packed nanopapers ( 6 – 9 ) and filaments ( 10 , 11 ) with tunable supermolecular nanostructures ( 12 , 13 ), and aerogels and foams ( 14 – 16 ). However, during extraction, processing, and use, CNs are subjected to complex stress environments that alter their morphology and mechanical properties.…”

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confidence: 99%

Cellulose crystals plastify by localized shear

Molnár

Rodney

Martoïa

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

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SignificanceWhile most attention has so far been devoted to the tensile properties of crystalline cellulose, the main elementary building block of plants, we show here using atomistic simulations that their shear is also an important mode of deformation, occurring at stress levels lower than tension with much larger ductility. We also demonstrate how crystalline defects like dislocations drastically facilitate plasticity. This analysis can be used as a basis for the micromechanical modeling of cellulose microfibrils that are currently considered as promising eco-friendly alternatives to synthetic fibers for structural materials.

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On the origins of the elasticity of cellulose nanofiber nanocomposites and nanopapers: a micromechanical approach

Abstract: The elastic properties of cellulose nanofibril (NFC) nanocomposites and nanopapers are predicted by a multiscale network model that shows that the deformation mechanisms are governed by the bonds between rigid NFC segments and in the kinked regions.

Cited by 22 publications

References 86 publications

Iα to Iβ mechano-conversion and amorphization in native cellulose simulated by crystal bending

Iα to Iβ mechano-conversion and amorphization in native cellulose simulated by crystal bending

Ice-Templated Porous Nanocellulose-Based Materials: Current Progress and Opportunities for Materials Engineering

Cellulose crystals plastify by localized shear

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