scholarly journals Effect of Secondary Carbon Nanofillers on the Electrical, Thermal, and Mechanical Properties of Conductive Hybrid Composites Based on Epoxy Resin and Graphite

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4169
Author(s):  
Marcel Zambrzycki ◽  
Krystian Sokolowski ◽  
Maciej Gubernat ◽  
Aneta Fraczek-Szczypta
Keyword(s):  
Mechanical Properties ◽  
Specific Surface ◽  
Epoxy Resin ◽  
Surface Area ◽  
Specific Surface Area ◽  
Hybrid Composites ◽  
Department Of Energy ◽  
Carbon Nanofillers ◽  
The Impact ◽  
Secondary Carbon

In this work, we present a comparative study of the impact of secondary carbon nanofillers on the electrical and thermal conductivity, thermal stability, and mechanical properties of hybrid conductive polymer composites (CPC) based on high loadings of synthetic graphite and epoxy resin. Two different carbon nanofillers were chosen for the investigation—low-cost multi-layered graphene nanoplatelets (GN) and carbon black (CB), which were aimed at improving the overall performance of composites. The samples were obtained by a simple, inexpensive, and effective compression molding technique, and were investigated by the means of, i.a., scanning electron microscopy, Raman spectroscopy, electrical conductivity measurements, laser flash analysis, and thermogravimetry. The tests performed revealed that, due to the exceptional electronic transport properties of GN, its relatively low specific surface area, good aspect ratio, and nanometric sizes of particles, a notable improvement in the overall characteristics of the composites (best results for 4 wt % of GN; σ = 266.7 S cm−1; λ = 40.6 W mK−1; fl. strength = 40.1 MPa). In turn, the addition of CB resulted in a limited improvement in mechanical properties, and a deterioration in electrical and thermal properties, mainly due to the too high specific surface area of this nanofiller. The results obtained were compared with US Department of Energy recommendations regarding properties of materials for bipolar plates in fuel cells. As shown, the materials developed significantly exceed the recommended values of the majority of the most important parameters, indicating high potential application of the composites obtained.

scholarly journals The Effects of Silica-Based Fillers on the Properties of Epoxy Molding Compounds

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1811 ◽  
Author(s):  
Mitja Linec ◽  
Branka Mušič
Keyword(s):  
Mechanical Properties ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Fused Silica ◽  
Spiral Flow ◽  
Scanning Calorimetry ◽  
Molding Compounds ◽  
Material Development ◽  
The Impact

Global design and manufacturing of the materials with superb properties remain one of the greatest challenges on the market. The future progress is orientated towards researches into the material development for the production of composites of better mechanical properties to the existing materials. In the field of advanced composites, epoxy molding compounds (EMCs) have attained dominance among the common materials due to their excellent properties that can be altered by adding different fillers. One of the main fillers is often based on silicon dioxide (SiO2). The concept of this study was to evaluate the effects of the selected silica-based fillers on the thermal, rheological, and mechanical properties of EMCs. Various types of fillers with SiO2, including crystalline silica and fused silica, were experimentally studied to clarify the impact of filler on final product. Fillers with different shape (scanning electron microscope, SEM), along with different specific surface area (specific surface area analyzer, BET method) and different chemical structure, were tested to explore their modifications on the EMCs. The influence of the fillers on the compound materials was determined with the spiral flow length (spiral flow test, EMMI), glass transition temperature (differential scanning calorimetry, DSC), and the viscosity (Torque Rheometer) of the composites.

scholarly journals Nanoporous Quasi-High-Entropy Alloy Microspheres

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 345 ◽  
Author(s):  
Lianzan Yang ◽  
Yongyan Li ◽  
Zhifeng Wang ◽  
Weimin Zhao ◽  
Chunling Qin
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Specific Surface Area ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Hierarchical Porous

High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.

Chemical EOR in Low Permeability Sandstone Reservoirs: Impact of Clay Content on the Transport of Polymer and Surfactant

2021 ◽  
Author(s):  
Imane Guetni ◽  
Claire Marlière ◽  
David Rousseau
Keyword(s):  
Porous Media ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Clay Content ◽  
Low Permeability ◽  
Depth Propagation ◽  
The Impact ◽  
Polymer Retention ◽  
Injection Strategies

Abstract Application of chemical enhanced oil recovery (C-EOR) processes to low-permeability sandstone reservoirs (in the 10-100 mD range) can be very challenging as strong retention and difficult in-depth propagation of polymer and surfactant can occur. Transport properties of C-EOR chemicals are particularly related to porous media mineralogy (clay content). The present experimental study aimed at identifying base mechanisms and providing general recommendations to design economically viable C-EOR injection strategies in low permeability clayey reservoirs. Polymer and surfactant injection corefloods were conducted using granular packs (quartz and clay mixtures) with similar petrophysical characteristics (permeability 70-130 mD) but having various mineralogical compositions (pure quartz sand, sand with 8 wt-% kaolinite and sand with 8 wt-% smectite). The granular packs were carefully characterized in terms of structure (SEM) and specific surface area (BET). The main observables from the coreflood tests were the resistance and residual resistance factors generated during the chemical injections, the irreversible polymer retention and the surfactant retention in various injection scenarios (polymer alone, surfactant alone, polymer and surfactant). A first, the impact of the clay contents on the retention of polymer and surfactant considered independently was examined. Coreflood results have shown that retention per unit mass of rock strongly increased in presence of both kaolinite and smectite, but not in the same way for both chemicals. For polymer, retention was about twice higher with kaolinite than with smectite, despite the fact that the measured specific surface area of the kaolinite was about 5 times less than that of the smectite. Conversely, for surfactant, retention was much higher with smectite than with kaolinite. Secondly, the impact of the presence of surfactant on the polymer in-depth propagation and retention was investigated in pure quartz and kaolinite-bearing porous media. In both mineralogies, the resistance factor quickly stabilized when polymer was injected alone whereas injection of larger solution volumes was required to reach stabilization when surfactant was present. In pure quartz, polymer retention was shown, surprisingly, to be one order of magnitude higher in presence of surfactant whereas with kaolinite, surfactant did not impact polymer retention. The results can be interpreted by considering adsorption-governed retention. The mechanistic pictures being that (a) large polymer macromolecules are not able to penetrate the porosity of smectite aggregates, whereas surfactant molecules can, and (b) that surfactant and polymer mixed adsorbed layers can be formed on surfaces with limited affinity for polymer. Overall, this study shows that C-EOR can be applied in low permeability reservoirs but that successful injection strategies will strongly depend on mineralogy.

Influence of Zinc Oxide Nanograins on Properties of Epoxidized Natural Rubber Vulcanizates

2017 ◽  
Vol 748 ◽  
pp. 79-83 ◽  
Author(s):  
Rudeerat Suntako
Keyword(s):  
Mechanical Properties ◽  
Zinc Oxide ◽  
Natural Rubber ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Epoxidized Natural Rubber ◽  
Precipitation Method ◽  
Cure Characteristics ◽  
Permanent Set

Zinc oxide (ZnO) nanograins are synthesized by precipitation method filled epoxidized natural rubber compared to conventional ZnO. The synthesized ZnO nanograins are characterized by X-ray diffraction and transmission electron microscopy and found that average primary size of ZnO synthesized around 40 nm and the specific surface area of 28.72 m2 g-1. Furthermore, the cure characteristics, rubber mechanical properties and permanent set were investigated. The obtained results are found that the ZnO nanograins significantly affected to cure characteristics, rubber mechanical properties and permanent set. This is due to small grain size and large specific surface area.

scholarly journals New Production Route of Magnesium Hydroxide and Related Environmental Impact

2020 ◽  
Vol 12 (21) ◽  
pp. 8822
Author(s):  
Andrzej Jarosinski ◽  
Piotr Radomski ◽  
Lukasz Lelek ◽  
Joanna Kulczycka
Keyword(s):  
Environmental Impact ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Magnesium Hydroxide ◽  
Flame Retardants ◽  
Polymeric Materials ◽  
New Production ◽  
Constant Flow Rate ◽  
The Impact

The paper presents research on a method of obtaining magnesium hydroxide from magnesium sulphate salts and NaOH. In order to acquire the desired and controlled properties, the method of precipitating in aqueous solutions by introducing a NaOH solution into a solution of MgSO4 has been applied. To get as stable a product as possible with graining, the introduction of NaOH takes place at a constant flow rate. In order to identify the environmental impact of the developed process, a life cycle assessment (LCA) has been made. The use of the proposed method for the synthesis of Mg(OH)2 incorporating washing with 25% ammonia solution and acetone enabled a product with a high specific surface area. The Mg(OH)2 obtained was characterised by a higher specific surface area than commercially available magnesium hydroxides that are used as additives for flame retardants in polymeric materials. This allows the material to be used as an anti-pyrogen for a wider group of polymeric materials. For the LCA analysis, two scenarios were assumed, from which the basic one included recovery of ammonia and acetone. The environmental analysis carried out confirmed the validity of this assumption, as it was stated that the main part of the impact was connected with the supply chain for the process examined.

scholarly journals Influence of Pluronic® P123 Addition in the Synthesis of Bulk Ni Promoted MoS2 Catalyst. Application to the Selective Hydrodesulfurization of Sulfur Model Molecules Representative of FCC Gasoline

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 793 ◽  
Author(s):  
Valentin Hetier ◽  
Diego Pena ◽  
Alexandre Carvalho ◽  
Laurence Courthéoux ◽  
Valérie Flaud ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Intrinsic Activity ◽  
Strong Increase ◽  
Similar Amount ◽  
X Ray ◽  
Mos2 Catalysts ◽  
The Impact

A way to improve hydrotreatment processes is to enhance the intrinsic activity of Ni or Co promoted MoS2 catalysts that are commonly used in such reactions. The aim of this work was to investigate the impact of the presence of Pluronic® P123 as a structuring agent during the synthesis of Ni promoted MoS2 catalysts (named NiMoS) in water at room temperature. A series of analyses, i.e., X-ray diffraction (XRD), chemical analysis, inductively coupled plasma mass spectrometry (ICP-MS), nitrogen adsorption-desorption isotherms, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), helped in characterizing the NiMoS-P123 and NiMoS catalysts, the latter being prepared in the absence of polymer. Both compounds contained MoS2 phase (~85 atomic% considering Mo atoms), a similar amount of mixed Ni-Mo-S phase (40–50% considering Ni) and some amount of NiS and Ni-oxidized impurity phases. The main differences between the two catalysts were a much larger specific surface area (126 m2·g−1 instead of 31 m²·g−1) and a better dispersion of the active phase as shown by the lower slab stacking (2.7 instead of 4.8) for NiMoS-P123, and the presence of C in NiMoS-P123 (9.4 wt.% instead of 0.6 wt.%), indicating an incomplete decomposition of the polymer during thermal treatment. Thanks to its larger specific surface area and lower slab stacking and therefore modification of active Mo site properties, the compound prepared in the presence of Pluronic® P123 exhibits a strong increase of the catalytic activity expressed per Mo atom for the transformation of 3-methylthiophene. Such improvement in catalytic activity was not observed for the transformation of benzothiophene likely due to poisonous residual carbon which results from the presence of Pluronic® P123 during the synthesis.

scholarly journals Thermal conductivity of polyvinylpolymethylsiloxane aerogels with high specific surface area

RSC Advances ◽  
2019 ◽  
Vol 9 (14) ◽  
pp. 7833-7841 ◽  
Author(s):  
Lukai Wang ◽  
Junzong Feng ◽  
Yonggang Jiang ◽  
Liangjun Li ◽  
Jian Feng
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Heat Insulation ◽  
High Specific Surface Area

The traditional SiO2 aerogels are difficult to apply in the fields of energy storage and heat insulation due to their poor mechanical properties.

Effect of Crosslink Density and Mechanical Properties on the Wear of Silica-Filled Styrene-Butadiene Rubbers

2005 ◽  
Author(s):  
Yoshitaka Uchiyama ◽  
Tomoaki Iwai ◽  
Naoya Amino ◽  
Kiichiro Shimosaka
Keyword(s):  
Mechanical Properties ◽  
Wear Rate ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Crosslink Density ◽  
Silane Coupling Agent ◽  
Wear Rates ◽  
Silane Coupling ◽  
Styrene Butadiene

In this study the effects of silica size (or specific surface area), mechanical properties and crosslink density on the wear of silica-filled SBRs (styrene butadiene rubbers) were examined. The modulus of each silica-filled SBR examined was proportional to crosslink density. The wear rate of silica-filled SBRs was reduced as the modulus and crosslink density increased. The wear rates increased as the specific surface area of the silica fill particles decreased, when the content of silane coupling agent was constant. As a result, the wear rate was shown to be lower as the modulus and crosslink density increased.

A Comparison Study on Microstructure and Mechanical Properties of Si3N4 Ceramic Prepared from MACS Powders

2007 ◽  
Vol 336-338 ◽  
pp. 1179-1181
Author(s):  
Ke Gang Ren ◽  
Ke Xin Chen ◽  
Hai Bo Jin ◽  
Xiao Shan Ning ◽  
He Ping Zhou
Keyword(s):  
Mechanical Properties ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Alpha Phase ◽  
Comparison Study ◽  
Sintering Aids ◽  
Pressing Method ◽  
Fine Powders ◽  
Microstructure And Mechanical Properties

In present work, ultra-fine powders with alpha phase content higher than 95 wt% and specific surface area of 15.33 m2/g were prepared by mechanical activated combustion synthesis (MACS) process. The sinterability of as-fabricated Si3N4 as well as the microstructure and mechanical properties of the sintered bulk were investigated by comparing with a kind of commercial available Si3N4 powders used as diluents in MACS process. Employing hot-pressing method, both powders were sintered equally by using Y2O3 and Al2O3 as sintering aids. Results showed that smaller particle size and higher specific surface area were obtained by MACS process when compared with the commercial one. Bulk Si3N4 appeared approximately the same relative density, hardness, strength and fracture toughness, however, proved to be higher while using MACS powders.

scholarly journals Endowing Acceptable Mechanical Properties of Segregated Conductive Polymer Composites with Enhanced Filler-Matrix Interfacial Interactions by Incorporating High Specific Surface Area Nanosized Carbon Black

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2074
Author(s):  
Huibin Cheng ◽  
Xiaoli Sun ◽  
Baoquan Huang ◽  
Liren Xiao ◽  
Qinghua Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Conductive Polymer ◽  
High Specific Surface Area ◽  
Emi Shielding ◽  
Interfacial Interactions ◽  
Emi Se

Tuning the high properties of segregated conductive polymer materials (CPCs) by incorporating nanoscale carbon fillers has drawn increasing attention in the industry and academy fields, although weak interfacial interaction of matrix-filler is a daunting challenge for high-loading CPCs. Herein, we present a facile and efficient strategy for preparing the segregated conducting ultra-high molecular weight polyethylene (UHMWPE)-based composites with acceptable mechanical properties. The interfacial interactions, mechanical properties, electrical properties and electromagnetic interference (EMI) shielding effectiveness (SE) of the UHMWPE/conducting carbon black (CCB) composites were investigated. The morphological and Raman mapping results showed that UHMWPE/high specific surface area CCB (h-CCB) composites demonstrate an obviously interfacial transition layer and strongly interfacial adhesion, as compared to UHMWPE/low specific surface area CCB (l-CCB) composites. Consequently, the high-loading UHMWPE/h-CCB composite (beyond 10 wt% CCB dosage) exhibits higher strength and elongation at break than the UHMWPE/l-CCB composite. Moreover, due to the formation of a densely stacked h-CCB network under the enhanced filler-matrix interfacial interactions, UHMWPE/h-CCB composite possesses a higher EMI SE than those of UHMWPE/l-CCB composites. The electrical conductivity and EMI SE value of the UHMWPE/h-CCB composite increase sharply with the increasing content of h-CCB. The EMI SE of UHMWPE/h-CCB composite with 10 wt% h-CCB is 22.3 dB at X-band, as four times that of the UHMWPE/l-CCB composite with same l-CCB dosage (5.6 dB). This work will help to manufacture a low-cost and high-performance EMI shielding material for modern electronic systems.

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