Highly conductive and intrinsically stretchable electrodes are vital components of soft electronics such as stretchable transistors and circuits, sensors and actuators, light-emitting diode arrays, ...and energy harvesting devices. Many kinds of conducting nanomaterials with outstanding electrical and mechanical properties have been integrated with elastomers to produce stretchable conductive nanocomposites. Understanding the characteristics of these nanocomposites and assessing the feasibility of their fabrication are therefore critical for the development of high-performance stretchable conductors and electronic devices. We herein summarise the recent advances in stretchable conductors based on the percolation networks of nanoscale conductive fillers in elastomeric media. After discussing the material-, dimension-, and size-dependent properties of conductive fillers and their implications, we highlight various techniques that are used to reduce the contact resistance between the conductive filler materials. Furthermore, we categorize elastomer matrices with different stretchabilities and mechanical properties based on their polymeric chain structures. Then, we discuss the fabrication techniques of stretchable conductive nanocomposites toward their use in soft electronics. Finally, we provide representative examples of stretchable device applications and conclude the review with a brief outlook for future research.
This article reviews the cascade strategy of stretchable conductive nanocomposites where various filler materials are processed for stretchable electronic applications.
Biogas is an increasingly attractive renewable resource, envisioned to secure future energy demands and help curb global climate change. To capitalize on this resource, membrane processes and ...state-of-the-art membranes must efficiently recover methane (CH4) from biogas by separating carbon dioxide (CO2). Composite (a.k.a. mixed-matrix) membranes, prepared from common polymers and rationally selected/engineered fillers, are highly promising for this application. This review comprehensively examines filler materials that are capable of enhancing the CO2/CH4 separation performance of polymeric membranes. Specifically, we highlight novel synthetic strategies for engineering filler materials to develop high-performance composite membranes. Besides, as the matrix components (polymers) of composite membranes largely dictate the overall gas separation performances, we introduce a new empirical metric, the “Filler Enhancement Index” (F index), to aid researchers in assessing the effectiveness of the fillers from a big data perspective. The F index systematically decouples the effect of polymer matrices and critically evaluates both conventional and emerging fillers to map out a future direction for next-generation (bio)gas separation membranes. Beyond biogas separation, this review is of relevance to a broader community with interests in composite membranes for other gas separation processes, as well as water treatment applications.
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IJS, KILJ, NUK, PNG, UL, UM
Honeycomb sandwich composites are suitable for making structural materials that are mainly characterized by their lightweight and high stiffness strength. The honeycomb structures filled with foam ...materials or granular materials concerning to the applications enhance the strength and the damping properties. In this paper, an emphasis has been provided for the comprehensive review of response of honeycomb sandwich structures in different conditions, namely, static, dynamic, and damping behaviors with and without filler material from an experimental and finite element simulation perspective. Various applications of honeycomb sandwich composites in different fields are also reviewed in this paper. Potential new directions in honeycomb sandwich composites are also identified in this paper in addition to the current practices. Conclusions and recommendations from different technical papers are reviewed by considering the honeycomb sandwich composites with filler materials. The given area of research seeks more scientific analysis, modeling, and experiments in future structural applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
4.
Mixed‐Matrix Membranes Dechnik, Janina; Gascon, Jorge; Doonan, Christian J. ...
Angewandte Chemie International Edition,
August 1, 2017, Volume:
56, Issue:
32
Journal Article
Peer reviewed
Open access
Research into extended porous materials such as metal‐organic frameworks (MOFs) and porous organic frameworks (POFs), as well as the analogous metal‐organic polyhedra (MOPs) and porous organic cages ...(POCs), has blossomed over the last decade. Given their chemical and structural variability and notable porosity, MOFs have been proposed as adsorbents for industrial gas separations and also as promising filler components for high‐performance mixed‐matrix membranes (MMMs). Research in this area has focused on enhancing the chemical compatibility of the MOF and polymer phases by judiciously functionalizing the organic linkers of the MOF, modifying the MOF surface chemistry, and, more recently, exploring how particle size, morphology, and distribution enhance separation performance. Other filler materials, including POFs, MOPs, and POCs, are also being explored as additives for MMMs and have shown remarkable anti‐aging performance and excellent chemical compatibility with commercially available polymers. This Review briefly outlines the state‐of‐the‐art in MOF‐MMM fabrication, and the more recent use of POFs and molecular additives.
Challenging separations: The need for greater energy efficiency and the maximum use of limited resources has focused attention on improved separation technologies. For gas separations, mixed‐matrix membranes can provide enhanced separation performance and lead to more energy‐efficient, sustainable, and cost‐effective commercial applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Composites have been found to be the most promising and discerning material available in this century. Presently, composites reinforced with fibers of synthetic or natural materials are gaining more ...importance as demands for lightweight materials with high strength for specific applications are growing in the market. Fiber-reinforced polymer composite offers not only high strength to weight ratio, but also reveals exceptional properties such as high durability; stiffness; damping property; flexural strength; and resistance to corrosion, wear, impact, and fire. These wide ranges of diverse features have led composite materials to find applications in mechanical, construction, aerospace, automobile, biomedical, marine, and many other manufacturing industries. Performance of composite materials predominantly depends on their constituent elements and manufacturing techniques, therefore, functional properties of various fibers available worldwide, their classifications, and the manufacturing techniques used to fabricate the composite materials need to be studied in order to figure out the optimized characteristic of the material for the desired application. An overview of a diverse range of fibers, their properties, functionality, classification, and various fiber composite manufacturing techniques is presented to discover the optimized fiber-reinforced composite material for significant applications. Their exceptional performance in the numerous fields of applications have made fiber-reinforced composite materials a promising alternative over solitary metals or alloys.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In den letzten Jahren sind wichtige Entwicklungen im Bereich der Schweißstromquellen und den Zusatzwerkstoffen für das Metall-Inertgas (MIG)-Schweißen von Magnesiumlegierungen gemacht worden. Diese ...Fortschritte führen zu einem wesentlich besseren Schweißprozeß und damit zu einem stark verbesserten Schweißergebnis. Von entscheidender Bedeutung für den Schweißprozeß ist die Energieeinbringung in den Draht. Die Schwierigkeiten resultieren aus den physikalischen Eigenschaften von Magnesium (Schmelzpunkt ca. 600 °C, Verdampfungspunkt ca. 1100 °C). Die Energiezuführung in den Draht muss so geregelt werden, dass es zwar zum Schmelzen, aber nicht zum Verdampfen des Drahtes kommt. Hierzu sind spezielle Stromquellenverläufe untersucht worden. Die Schwingfestigkeit der untersuchten Magnesiumlegierungen liegt im geschweißten Zustand bei ca. 50 % des Grundwerkstoffs. Bei abgearbeiteter Naht ergeben sich Festigkeiten von bis zu 75 % des Grundwerkstoff wertes.
Abstract
The requirement for a lightweight bipolar plate (BP) for Proton Exchange Membrane Fuel Cell (PEMFC) is increasing to make it feasible to power hydrogen fuel cell electric vehicles. Composite ...BP with carbon materials as conductive fillers and polymer as the binder are preferable over pure graphite and metallic BP. This study investigates the effect of Surface‐enhanced flake graphite (SEFG) as a novel filler material in composite BP. A composite BP is developed with Epoxy Resin (ER) as the binder and Natural Flake Graphite (NFG), Carbon Black (CB) and SEFG as conductive fillers. Composite BP fabricated with 10 vol% SEFG, 10 vol% CB, and 40 vol% NFG exhibited an electrical conductivity of 158 S cm
−1
, flexural strength of 38 MPa, water contact angle of 90.41
0
and corrosion current density of 0.261 μA cm
−2
. The composite BP also achieved a density of 1.55 g cm
−3
, water absorption of 0.6% and thermal conductivity of 3.6 W m
−1
K
−1
at 120°C. These results are highly favorable for BPs used in PEMFC. This paper provides an insight into using surface‐modified conductive carbon filler materials to develop composite BP for application in PEMFC.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Lightweight materials are of paramount importance to reduce energy consumption and emissions in today's society. For materials to qualify for widespread use in lightweight structural assembly, they ...must be weldable or joinable, which has been a long-standing issue for high strength aluminum alloys, such as 7075 (AA7075) due to their hot crack susceptibility during fusion welding. Here, we show that AA7075 can be safely arc welded without hot cracks by introducing nanoparticle-enabled phase control during welding. Joints welded with an AA7075 filler rod containing TiC nanoparticles not only exhibit fine globular grains and a modified secondary phase, both which intrinsically eliminate the materials hot crack susceptibility, but moreover show exceptional tensile strength in both as-welded and post-weld heat-treated conditions. This rather simple twist to the filler material of a fusion weld could be generally applied to a wide range of hot crack susceptible materials.
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.
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BFBNIB, NMLJ, NUK, ODKLJ, PNG, SAZU, UL, UM, UPUK
•Laser micro-welding of aluminum-copper dissimilar metals are reviewed entirely.•Laser micro-welding parameters of aluminum-copper dissimilar metals are discussed in detail.•Filler materials of laser ...micro-welding of aluminum-copper dissimilar metals are summarized.
In the microelectronics industry, the high thermal and electrical conductivity of copper (Cu), the low volume density and the high efficiency of aluminum (Al) are extremely attractive. The unstable energy absorptivity and welding process, however, were caused by the high reflectivity and high thermal conductivity between Al and Cu. Meanwhile, brittle and complex intermetallic compounds (IMCs), such as Cu2Al and Cu2Al2 and so on were formed easily when Cu and Al were fully mixed in the molten pool. In recent years, electronic packaging, battery components of new energy automobiles and other fields, laser micro-welding of Al-Cu dissimilar metals have been used widely. Laser micro-welding technology is superior to others micro-welding technology owning to its higher power density and unique controllability. In this paper, the laser micro-welding process of Al-Cu dissimilar metals and the effects of welding parameters including laser power, beam diameter, laser pulse and scanning mode and so on were discussed in detail. Filler materials and solder systems of laser micro-welding of Al-Cu dissimilar metals were summarized. The results showed that the tensile/shear strength of the good Al-Cu dissimilar joints was as strong as Al base metals, which was obtained when the IMCs layer was between 0.2 and 0.5 μm and the Cu content was less than 50%. In terms of the problems existing in laser micro-welding of Al-Cu dissimilar metals, some possible solutions and development tendency were reviewed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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