Outstanding Toughness of Cherry Bark Achieved by Helical Spring Structure of Rigid Cellulose Fiber Combined with Flexible Layers of Lipid Polymers

Kobayashi, Kazunori; Ura, Yoko; Kimura, Satoshi; Sugiyama, Junji

doi:10.1002/adma.201705315

Cited by 17 publications

(17 citation statements)

References 22 publications

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“…[ 56 ] Although not a bulk wood sample, exceptionally high strains to failure have been observed for cherry bark ( Cerasus sargentii) by Kobayashi et al. [ 57 ] Fibril angles of >70°, indicative of a helical structure to the cellulose, have been observed for this material ( Figure a). These helical microfibrils are also lignified.…”

Section: X‐ray Diffraction Studies On Wood Microfibrillar Features and Mechanicsmentioning

confidence: 80%

“…Kobayashi et al. [ 57 ] used synchrotron X‐ray diffraction to follow the change in the fibril angle with tensile deformation, providing a correlation with mechanical properties (Figure 5b). It was noted that these stress–strain curves were reminiscent of a thermoplastic polymer, leading to a high “toughness” (or work of fracture; ≈50 MJ m −3 ).…”

Section: X‐ray Diffraction Studies On Wood Microfibrillar Features and Mechanicsmentioning

confidence: 99%

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Beyond What Meets the Eye: Imaging and Imagining Wood Mechanical–Structural Properties

2020

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Wood presents a hierarchical structure, containing features at all length scales: from the tracheids or vessels that make up its cellular structure, through to the microfibrils within the cell walls, down to the molecular architecture of the cellulose, lignin, and hemicelluloses that comprise its chemical makeup. This structure renders it with high mechanical (e.g., modulus and strength) and interesting physical (e.g., optical) properties. A better understanding of this structure, and how it plays a role in governing mechanical and other physical parameters, will help to better exploit this sustainable resource. Here, recent developments on the use of advanced imaging techniques for studying the structural properties of wood in relation to its mechanical properties are explored. The focus is on synchrotron nuclear magnetic resonance spectroscopy, X‐ray diffraction, X‐ray tomographical imaging, Raman and infrared spectroscopies, confocal microscopy, electron microscopy, and atomic force microscopy. Critical discussion on the role of imaging techniques and how fields are developing rapidly to incorporate both spatial and temporal ranges of analysis is presented.

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Section: X‐ray Diffraction Studies On Wood Microfibrillar Features and Mechanicsmentioning

confidence: 80%

Section: X‐ray Diffraction Studies On Wood Microfibrillar Features and Mechanicsmentioning

confidence: 99%

Beyond What Meets the Eye: Imaging and Imagining Wood Mechanical–Structural Properties

2020

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“…Cherry cork has been used as a Japanese traditional craft ("Kabazaiku") because of its smooth surface and beautiful glossy, dark red color. In addition, the mechanical properties of cherry cork are notable: extensibility greater than 120%, Young's modulus 0.9-1.6 GPa, and toughness approximately 40 GPa in the tangential direction (Kobayashi et al 2018;Xu et al 1997). These values surpass the tensile properties of Q. suber cork (Anjos et al 2008;.…”

Section: Introductionmentioning

confidence: 99%

Histochemical structure and tensile properties of birch cork cell walls

Kiyoto

Sugiyama

2021

Cellulose

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Tensile tests of birch cork were performed in the tangential direction. Birch cork in the wet state showed signi cantly higher extensibility and toughness than those in the oven-dried state. The histochemical structure of birch cork was investigated by microscopic observation and spectroscopic analysis. Birch cork cell walls showed a three-layered structure. In transmission electron micrographs, osmium tetroxide stained the outer and inner layers, whereas potassium permanganate stained the middle and inner layers. After chemical treatment to remove suberin and lignin, the outer and inner layers disappeared and Fouriertransformed infrared spectra showed the cellulose I pattern. Polarizing light micrographs indicated that molecular chains in the outer and inner layers were oriented perpendicular to suberin lamination, whereas those in the inner layer showed longitudinal orientation. These results suggested that the outer and inner layers mainly consist of suberin, whereas the middle layer and compound middle lamella consist of lignin, cellulose, and other polysaccharides. We hypothesized a hierarchical model of the birch cork cell wall. The ligni ed cell wall with helical arrangement of cellulose micro brils is sandwiched between two suberized walls. Cellulose micro brils in the middle layer act like a spring and bear tensile loads. In the wet state, water and cellulose in the compound middle lamella transfer tensile stress between cells. In the dried state, this stress-transferal system functions poorly and fewer cells bear stress. Suberin in the outer and inner layers prevents absolute drying to maintain mechanical properties of the bark and to bear tensile stress caused by trunk diameter growth.

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“…[ 11–18 ] Moreover, cellulose nanotechnology, including TEMPO‐oxidized, mechanical chemistry methods, and acid treatment, have been developed to produce cellulose nanowhiskers and nanofibers (cellulose I) via the “top‐down” approach, which can also be used for the fabrication of various robust cellulose materials. [ 19–39 ] The dissolution and regeneration process can transform cellulose I into cellulose II, in which high‐performance materials can be constructed though the “bottom‐up” approach. [ 9,40–43 ] The difference between cellulose I and cellulose II is the hydrogen‐bond pattern in their crystalline structure, where cellulose I has a parallel orientation of the macromolecular chains, whereas cellulose II has an antiparallel orientation.…”

Section: Introductionmentioning

confidence: 99%

Recent Progress in High‐Strength and Robust Regenerated Cellulose Materials

et al. 2020

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High‐strength petroleum‐based materials like plastics have been widely used in various fields, but their nonbiodegradability has caused serious pollution problems. Cellulose, as the most abundant sustainable polymer, has a great chance to act as the ideal substitute for plastics due to its low cost, wide availability, biodegradability, etc. Herein, the recent achievements for developing cellulose “green” solvents and regenerated cellulose materials with high strength via the “bottom‐up” route are presented. Cellulose can be regenerated to produce films/membranes, hydrogels/aerogels, filaments/fibers, microspheres/beads, bioplastics, etc., which show potential applications in textiles, biomedicine, energy storage, packaging, etc. Importantly, these cellulose‐based materials can be biodegraded in soil and oceans, reducing environmental pollution. The cellulose solvents, dissolving mechanism, and strategies for constructing the regenerated cellulose functional materials with high strength and performances, together with the current achievements and urgent challenges are summarized, and some perspectives are also proposed. The near future will be an exciting era for high‐strength biodegradable and renewable materials. The hope is that many environmentally friendly materials with good properties and low cost will be produced for commercial use, which will be beneficial for sustainable development in the world.

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Outstanding Toughness of Cherry Bark Achieved by Helical Spring Structure of Rigid Cellulose Fiber Combined with Flexible Layers of Lipid Polymers

Cited by 17 publications

References 22 publications

Beyond What Meets the Eye: Imaging and Imagining Wood Mechanical–Structural Properties

Beyond What Meets the Eye: Imaging and Imagining Wood Mechanical–Structural Properties

Histochemical structure and tensile properties of birch cork cell walls

Recent Progress in High‐Strength and Robust Regenerated Cellulose Materials

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