scholarly journals Anomalous scaling law of strength and toughness of cellulose nanopaper

2015 ◽  
Vol 112 (29) ◽  
pp. 8971-8976 ◽  
Author(s):  
Hongli Zhu ◽  
Shuze Zhu ◽  
Zheng Jia ◽  
Sepideh Parvinian ◽  
Yuanyuan Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Scaling Law ◽  
Functional Materials ◽  
Material Design ◽  
Cellulose Fibers ◽  
Building Blocks ◽  
General Mechanism ◽  
Intrinsic Defect ◽  
Cellulose Nanopaper ◽  
Strength And Toughness

The quest for both strength and toughness is perpetual in advanced material design; unfortunately, these two mechanical properties are generally mutually exclusive. So far there exists only limited success of attaining both strength and toughness, which often needs material-specific, complicated, or expensive synthesis processes and thus can hardly be applicable to other materials. A general mechanism to address the conflict between strength and toughness still remains elusive. Here we report a first-of-its-kind study of the dependence of strength and toughness of cellulose nanopaper on the size of the constituent cellulose fibers. Surprisingly, we find that both the strength and toughness of cellulose nanopaper increase simultaneously (40 and 130 times, respectively) as the size of the constituent cellulose fibers decreases (from a mean diameter of 27 μm to 11 nm), revealing an anomalous but highly desirable scaling law of the mechanical properties of cellulose nanopaper: the smaller, the stronger and the tougher. Further fundamental mechanistic studies reveal that reduced intrinsic defect size and facile (re)formation of strong hydrogen bonding among cellulose molecular chains is the underlying key to this new scaling law of mechanical properties. These mechanistic findings are generally applicable to other material building blocks, and therefore open up abundant opportunities to use the fundamental bottom-up strategy to design a new class of functional materials that are both strong and tough.

Mechanics of Strong and Tough Cellulose Nanopaper

2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Qinghua Meng ◽  
Tie Jun Wang
Keyword(s):  
Mechanical Properties ◽  
Cellulose Nanofibrils ◽  
High Strength ◽  
Material Design ◽  
Design Strategy ◽  
Mechanical Modeling ◽  
Structure Property ◽  
Porous Network ◽  
Cellulose Nanopaper ◽  
Strength And Toughness

Cellulose nanopaper, which consists of a porous network of cellulose nanofibrils (CNFs), exhibits excellent mechanical properties with high strength and toughness. The physical mechanisms, including a realizable reduction of defect size in the nanopaper and facile formation/reformation of hydrogen bonds among CNFs, suggest a bottom-up material design strategy to address the conflict between strength and toughness. A thorough exploration of the rich potential of such a design strategy requires a fundamental understanding of its mechanical behavior. In this review, we supply a comprehensive perspective on advances in cellulose nanopaper mechanics over the most recent two decades from the three aspects of mechanical properties, structure–property relationship and microstructure-based mechanical modeling. We discuss the effects of size, orientation, polymerization degree, and isolate origins of CNFs; density or porosity and humidity of nanopaper; and hemicellulose and lignin on the mechanical properties of cellulose nanopaper. We also discuss the similarities and differences in the microstructure, mechanical properties, and toughening mechanisms between cellulose nanopaper and cellulose nanocrystal (CNC) nanopaper, chitin nanopaper, carbon nanotube (CNT) nanopaper, and graphene nanopaper. Finally, we present the ideas, status quo, and future trends in mechanical modeling of cellulose nanopaper, including atomistic- and microscale-level numerical modeling, and theoretical modeling. This review serves as a modest spur intended to induce scientists to present their valuable contributions and especially to design more advanced cellulose nanopapers and promote the development of their mechanics.

scholarly journals Co-continuous network polymers using epoxy monolith for the design of tough materials

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ren Tominaga ◽  
Yukihiro Nishimura ◽  
Yasuhito Suzuki ◽  
Yoshihiro Takeda ◽  
Masaru Kotera ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Material Design ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Polymer Materials ◽  
Scanning Calorimetry ◽  
Electron Microscopic ◽  
Network Polymers ◽  
Strength And Toughness

AbstractHigh-performance polymer materials that can exhibit distinguished mechanical properties have been developed based on material design considering energy dissipation by sacrificial bond dissociation. We now propose co-continuous network polymers (CNPs) for the design of tough polymer materials. CNP is a new composite material fabricated by filling the three-dimensionally continuous pores of a hard epoxy monolith with any cross-linked polymer having a low glass transition temperature (Tg). The structure and mechanical properties of the CNPs containing epoxy resins, thiol-ene thermosets, and polyacrylates as the low-Tg components were investigated by differential scanning calorimetry, dynamic mechanical analysis, tensile tests as well as scanning electron microscopic observations and non-destructive 3D X-ray imaging in order to clarify a mechanism for exhibiting an excellent strength and toughness. It has been demonstrated that the mechanical properties and fractural behavior of the CNPs significantly depend on the network structure of the filler polymers, and that a simultaneous high strength and toughness are achieved via the sacrificial fracture mechanism of epoxy-based hard materials with co-continuous network structures.

Ultrasonic Torsion Welding of Aging Resistant Al/CFRP Joints - Concepts, Mechanical and Microstructural Properties

2017 ◽  
Vol 742 ◽  
pp. 395-400 ◽  
Author(s):  
Florian Staab ◽  
Frank Balle ◽  
Johannes Born
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Materials Science ◽  
Dissimilar Materials ◽  
Material Design ◽  
Ultrasonic Welding ◽  
Fatigue Properties ◽  
Aviation Industry ◽  
Efficient Design ◽  
Engineering Structures

Multi-material-design offers high potential for weight saving and optimization of engineering structures but inherits challenges as well, especially robust joining methods and long-term properties of hybrid structures. The application of joining techniques like ultrasonic welding allows a very efficient design of multi-material-components to enable further use of material specific advantages and are superior concerning mechanical properties.The Institute of Materials Science and Engineering of the University of Kaiserslautern (WKK) has a long-time experience on ultrasonic welding of dissimilar materials, for example different kinds of CFRP, light metals, steels or even glasses and ceramics. The mechanical properties are mostly optimized by using ideal process parameters, determined through statistical test planning methods.This gained knowledge is now to be transferred to application in aviation industry in cooperation with CTC GmbH and Airbus Operations GmbH. Therefore aircraft-related materials are joined by ultrasonic welding. The applied process parameters are recorded and analyzed in detail to be interlinked with the resulting mechanical properties of the hybrid joints. Aircraft derived multi-material demonstrators will be designed, manufactured and characterized with respect to their monotonic and fatigue properties as well as their resistance to aging.

scholarly journals Nanostructure, Self-Assembly, Mechanical Properties, and Antioxidant Activity of a Lupin-Derived Peptide Hydrogel

Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 294
Author(s):  
Raffaele Pugliese ◽  
Anna Arnoldi ◽  
Carmen Lammi
Keyword(s):  
Mechanical Properties ◽  
Antioxidant Activity ◽  
Self Assembly ◽  
Antioxidant Activities ◽  
Functional Materials ◽  
Cd Spectroscopy ◽  
Beneficial Effects ◽  
Naturally Occurring ◽  
New Research ◽  
Peptide Hydrogel

Naturally occurring food peptides are frequently used in the life sciences due to their beneficial effects through their impact on specific biochemical pathways. Furthermore, they are often leveraged for applications in areas as diverse as bioengineering, medicine, agriculture, and even fashion. However, progress toward understanding their self-assembling properties as functional materials are often hindered by their long aromatic and charged residue-enriched sequences encrypted in the parent protein sequence. In this study, we elucidate the nanostructure and the hierarchical self-assembly propensity of a lupin-derived peptide which belongs to the α-conglutin (11S globulin, legumin-like protein), with a straightforward N-terminal biotinylated oligoglycine tag-based methodology for controlling the nanostructures, biomechanics, and biological features. Extensive characterization was performed via Circular Dichroism (CD) spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR), rheological measurements, and Atomic Force Microscopy (AFM) analyses. By using the biotin tag, we obtained a thixotropic lupin-derived peptide hydrogel (named BT13) with tunable mechanical properties (from 2 to 11 kPa), without impairing its spontaneous formation of β-sheet secondary structures. Lastly, we demonstrated that this hydrogel has antioxidant activity. Altogether, our findings address multiple challenges associated with the development of naturally occurring food peptide-based hydrogels, offering a new tool to both fine tune the mechanical properties and tailor the antioxidant activities, providing new research directions across food chemistry, biochemistry, and bioengineering.

scholarly journals Influence of Alkali Treatment on the Microstructure and Mechanical Properties of Coir and Abaca Fibers

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2636
Author(s):  
Petr Valášek ◽  
Miroslav Müller ◽  
Vladimír Šleger ◽  
Viktor Kolář ◽  
Monika Hromasová ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Alkali Treatment ◽  
Fiber Surface ◽  
Cellulose Fibers ◽  
Sem Analysis ◽  
Experimental Program ◽  
Time Interval ◽  
The European Union ◽  
Vegetable Fibers

Composite materials with natural fillers have been increasingly used as an alternative to synthetically produced materials. This trend is visible from a representation of polymeric composites with natural cellulose fibers in the automotive industry of the European Union. This trend is entirely logical, owing to a preference for renewable resources. The experimental program itself follows pronounced hypotheses and focuses on a description of the mechanical properties of untreated and alkali-treated natural vegetable fibers, coconut and abaca fibers. These fibers have great potential for use in composite materials. The results and discussion sections contribute to an introduction of an individual methodology for mechanical property assessment of cellulose fibers, and allows for a clear definition of an optimal process of alkalization dependent on the content of hemicellulose and lignin in vegetable fibers. The aim of this research was to investigate the influence of alkali treatment on the surface microstructure and tensile properties of coir and abaca fibers. These fibers were immersed into a 5% solution of NaOH at laboratory temperature for a time interval of 30 min, 1 h, 2 h, 3 h, 6 h, 12 h, 24 h, and 48 h, rinsed and dried. The fiber surface microstructures before and after the alkali treatment were evaluated by SEM (scanning electron microscopy). SEM analysis showed that the alkali treatment in the NaOH solution led to a gradual connective material removal from the fiber surface. The effect of the alkali is evident from the visible changes on the surface of the fibers.

scholarly journals Core-Substituted Naphthalene-diimides (cNDI) and Related Derivatives: Versatile Scaffold for Supramolecular Assembly and Functional Materials

2021 ◽  
Author(s):  
Anurag Mukherjee ◽  
Suhrit Ghosh
Keyword(s):  
Photophysical Properties ◽  
Supramolecular Assembly ◽  
Functional Materials ◽  
Building Blocks ◽  
Short Review ◽  
Molecular Engineering ◽  
Organic Optoelectronics ◽  
Naphthalene Diimide ◽  
Naphthalene Diimides ◽  
Derivatives Of

Naphthalene-diimide (NDI) derived building blocks have been explored extensively for supramolecular assembly as they exhibit attractive photophysical properties, suitable for applications in organic optoelectronics. Core-substituted derivatives of the NDI chromophore (cNDI) differ significantly from the parent NDI dye in terms of optical and redox properties. Adequate molecular engineering opportunities and substitution-dependent tunable optoelectronic properties make cNDI derivatives highly promising candidates for supramolecular assembly and functional material. This short review discusses recent development in the area of functional supramolecular assemblies based on cNDIs and related molecules.

scholarly journals Amyloid fibril-directed synthesis of silica core–shell nanofilaments, gels, and aerogels

2019 ◽  
Vol 116 (10) ◽  
pp. 4012-4017 ◽  
Author(s):  
Yiping Cao ◽  
Sreenath Bolisetty ◽  
Gianna Wolfisberg ◽  
Jozef Adamcik ◽  
Raffaele Mezzenga
Keyword(s):  
Amyloid Fibril ◽  
Functional Materials ◽  
Building Blocks ◽  
Inorganic Materials ◽  
Core Shell ◽  
Shear Stresses ◽  
Bending Rigidity ◽  
Widespread Application ◽  
Nonmonotonic Dependence ◽  
Silica Core

Amyloid fibrils have evolved from purely pathological materials implicated in neurodegenerative diseases to efficient templates for last-generation functional materials and nanotechnologies. Due to their high intrinsic stiffness and extreme aspect ratio, amyloid fibril hydrogels can serve as ideal building blocks for material design and synthesis. Yet, in these gels, stiffness is generally not paired by toughness, and their fragile nature hinders significantly their widespread application. Here we introduce an amyloid-assisted biosilicification process, which leads to the formation of silicified nanofibrils (fibril–silica core–shell nanofilaments) with stiffness up to and beyond ∼20 GPa, approaching the Young’s moduli of many metal alloys and inorganic materials. The silica shell endows the silicified fibrils with large bending rigidity, reflected in hydrogels with elasticity three orders of magnitude beyond conventional amyloid fibril hydrogels. A constitutive theoretical model is proposed that, despite its simplicity, quantitatively interprets the nonmonotonic dependence of the gel elasticity upon the filaments bundling promoted by shear stresses. The application of these hybrid silica–amyloid hydrogels is demonstrated on the fabrication of mechanically stable aerogels generated via sequential solvent exchange, supercriticalCO2removal, and calcination of the amyloid core, leading to aerogels of specific surface area as high as 993m2/g, among the highest values ever reported for aerogels. We finally show that the scope of amyloid hydrogels can be expanded considerably by generating double networks of amyloid and hydrophilic polymers, which combine excellent stiffness and toughness beyond those of each of the constitutive individual networks.

Microstructure and Mechanical Properties of ZrB2/h-BN Multiphase Ceramics by Low-Temperature Reactive Sintering

2016 ◽  
Vol 697 ◽  
pp. 510-514 ◽  
Author(s):  
Feng Rui Zhai ◽  
Ke Shan ◽  
Ruo Meng Xu ◽  
Min Lu ◽  
Zhong Zhou Yi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Fracture Strength ◽  
Solid Phase ◽  
Raw Materials ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Microstructure And Mechanical Properties ◽  
Multiphase Ceramics ◽  
Strength And Toughness

In the present paper, the ZrB2/h-BN multiphase ceramics were fabricated by SPS (spark plasma sintering) technology at lower sintering temperature using h-BN, ZrO2, AlN and Si as raw materials and B2O3 as a sintering aid. The phase constitution and microstructure of specimens were analyzed by XRD and SEM. Moreover, the effects of different sintering pressures on the densification, microstructure and mechanical properties of ZrB2/h-BN multiphase ceramics were also systematically investigated. The results show that the ZrB2 was obtained through solid phase reaction at different sintering pressures, and increasing sintering pressure could accelerate the formation of ZrB2 phase. As the sintering pressure increasing, the fracture strength and toughness of the sintered samples had a similar increasing tendency as the relative density. The better comprehensive properties were obtained at given sintering pressure of 50MPa, and the relative density, fracture strength and toughness reached about 93.4%, 321MPa and 3.3MPa·m1/2, respectively. The SEM analysis shows that the h-BN grains were fine and uniform, and the effect of sintering pressure on grain size was inconspicuous. The distribution of grain is random cross array, and the fracture texture was more obvious with the increase of sintering pressure. The fracture mode of sintered samples remained intergranular fracture mechanism as sintering pressure changed, and the grain refinement, grain pullout and crack deflection helped to increase the mechanical properties.

Research on Mechanical Properties of Several New Regenerated Cellulose Fibers

2011 ◽  
Vol 332-334 ◽  
pp. 489-495 ◽  
Author(s):  
Rong Zhou ◽  
Ming Xia Yang
Keyword(s):  
Mechanical Properties ◽  
Phase Change Materials ◽  
Cellulose Fiber ◽  
Cellulose Fibers ◽  
Regenerated Cellulose ◽  
Pulp Fiber ◽  
Pulp Fibers ◽  
Bast Fiber ◽  
Bamboo Pulp ◽  
Lyocell Fiber

Regenerated cellulose fiber is the most widely-used and most variety of cellulose fiber. Five categories and ten kinds of fibers such as lyocell fiber, modal fiber, bamboo pulp fiber, sheng-bast fiber, Outlast viscose fiber were chosen as the research object. The strength property and elasticity of fibers in dry and wet state were tested and analysis. The comprehensive performances of fabrics were studied and mechanical properties of the fibers were listed in the order from good to bad by grey clustering analysis. The results show lyocell G100 and lyocell LF have better comprehensive mechanical properties ,while other new regenerated cellulose fibers’ comprehensive mechanical properties are general. Among these fibers modal fiber’s comprehensive mechanical properties are slightly better than sheng-bast fibers’ and bamboo pulp fibers’. Modal fiber, sheng-bast fiber and Bamboo pulp fiber have no significantly poor single parameter and all of them have better comprehensive mechanical properties than various viscose fibers. Outlast viscose in which has been added phase change materials sensitive to temperature by Microcapsule techniques fundamentally keeps similar comprehensive mechanical properties with other regenerated cellulose fibers,but its properties decline slightly .

scholarly journals Properties of High-Strength Flowable Mortar Reinforced with Palm Fibers

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Eethar Thanon Dawood ◽  
Mahyuddin Ramli
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Test Results ◽  
Palm Fiber ◽  
Toughness Index ◽  
Strength And Toughness

This study was conducted to determine some physical and mechanical properties of high-strength flowable mortar reinforced with different percentages of palm fiber (0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6% as volumetric fractions). The density, compressive strength, flexural strength, and toughness index were tested to determine the mechanical properties of this mortar. Test results illustrate that the inclusion of this fiber reduces the density of mortar. The use of 0.6% of palm fiber increases the compressive strength and flexural strength by about 15.1%, and 16%, respectively; besides, the toughness index (I5) of the high-strength flowable mortar has been significantly enhanced by the use of 1% and more of palm fiber.

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