https://cyberleninka.org/article/n/768408.pdf

Mechanical properties of graphene and graphene-based nanocomposites

Electrically conductive composites comprising polymers and graphene are extremely versatile and have a wide range of potential applications. The conductivity of these composites depends on the choice of polymer matrix, the type of graphene filler, the processing methodology, and any post-production treatments. In this review, we discuss the progress in graphene-polymer composites for electrical applications. Graphene filler types are reviewed, the progress in modelling these composites is outlined, the current optimal composites are presented, and the example of strain sensors is used to demonstrate their application.

/pdf/electrical-percolation-in-graphene-polymer-composites-4qq5g8p2if.pdf

Electrical percolation in graphene-polymer composites

Various methods have been exploited to replicate nacre features into artificial structural materials with impressive structural and mechanical similarity. However, it is still very challenging to produce nacre-mimetics in three-dimensional bulk form, especially for further scale-up. Herein, we demonstrate that large-sized, three-dimensional bulk artificial nacre with comprehensive mimicry of the hierarchical structures and the toughening mechanisms of natural nacre can be facilely fabricated via a bottom-up assembly process based on laminating pre-fabricated two-dimensional nacre-mimetic films. By optimizing the hierarchical architecture from molecular level to macroscopic level, the mechanical performance of the artificial nacre is superior to that of natural nacre and many engineering materials. This bottom-up strategy has no size restriction or fundamental barrier for further scale-up, and can be easily extended to other material systems, opening an avenue for mass production of high-performance bulk nacre-mimetic structural materials in an efficient and cost-effective way for practical applications.Artificial materials that replicate the mechanical properties of nacre represent important structural materials, but are difficult to produce in bulk. Here, the authors exploit the bottom-up assembly of 2D nacre-mimetic films to fabricate 3D bulk artificial nacre with an optimized architecture and excellent mechanical properties.

Mass production of bulk artificial nacre with excellent mechanical properties

https://espace.library.uq.edu.au/view/UQ:416842/UQ416842_OA.pdf

Dynamic instability of functionally graded multilayer graphene nanocomposite beams in thermal environment

Aligning graphene in bulk copper: Nacre-inspired nanolaminated architecture coupled with in-situ processing for enhanced mechanical properties and high electrical conductivity

Two-dimensional (2D) materials can uniquely span the physical dimensions of a surrounding composite matrix in the limit of maximum reinforcement. However, the alignment and assembly of continuous 2D components at high volume fraction remain challenging. We use a stacking and folding method to generate aligned graphene/polycarbonate composites with as many as 320 parallel layers spanning 0.032 to 0.11 millimeters in thickness that significantly increases the effective elastic modulus and strength at exceptionally low volume fractions of only 0.082%. An analogous transverse shear scrolling method generates Archimedean spiral fibers that demonstrate exotic, telescoping elongation at break of 110%, or 30 times greater than Kevlar. Both composites retain anisotropic electrical conduction along the graphene planar axis and transparency. These composites promise substantial mechanical reinforcement, electrical, and optical properties at highly reduced volume fraction.

https://science.sciencemag.org/content/sci/353/6297/364.full.pdf

Layered and scrolled nanocomposites with aligned semi-infinite graphene inclusions at the platelet limit

Conformal atomic layer deposition (ALD) of Al2O3 and TiO2 thin films on Kevlar®, poly(p-phenylene terephthalamide) (PPTA) fibers at 50 and 100 °C affects the fiber cut resistance. Systematic studies of ALD coatings between 10 to 400 A thick formed at 50 and 100 °C revealed excellent conformality, and trends in cutting performance depended on materials and process details. A 50 A/50 A TiO2/Al2O3 bilayer formed at 50 °C increased cut resistance of PPTA by 30% compared to untreated fiber materials. In situ infrared analysis shows that trimethylaluminum (TMA) Al2O3 precursor reacts sub-surface with PPTA and tends to degraded mechanical performance. The TiCl4 TiO2 precursor reacts to form a barrier that limits TMA/PPTA interactions, allowing a harder Al2O3 layer to form on top of TiO2. The thin ALD coatings do not substantially affect durability, flexibility, or weight of the PPTA, making ALD a potentially viable means to enhance the protective properties of Kevlar and other polymer fiber systems.

Improved cut-resistance of Kevlar® using controlled interface reactions during atomic layer deposition of ultrathin (<50 Å) inorganic coatings

Single high-performance fibers (Kevlar® K129, Twaron® 2040, Technora® T200, Dyneema® SK76, Zylon® AS, Vectran® HT, and S-glass) are subject to lateral cutting action by an industrial blade. Due to ...

Statistical cut response of high-performance single fibers

http://manuscript.elsevier.com/S1044580321008366/pdf/S1044580321008366.pdf

Physical simulations of heat-affected zone microstructures to compare weldability characteristics of additively manufactured and wrought 17-4 stainless steel

Joshua K. Taggart-Scarff

Papers

Layered and scrolled nanocomposites with aligned semi-infinite graphene inclusions at the platelet limit

Improved cut-resistance of Kevlar® using controlled interface reactions during atomic layer deposition of ultrathin (<50 Å) inorganic coatings

Statistical cut response of high-performance single fibers

Physical simulations of heat-affected zone microstructures to compare weldability characteristics of additively manufactured and wrought 17-4 stainless steel