scholarly journals Influence of Silica Specific Surface Area on the Viscoelastic and Fatigue Behaviors of Silica-Filled SBR Composites

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3094
Author(s):  
Hiron Raja Padmanathan ◽  
Carlos Eloy Federico ◽  
Frédéric Addiego ◽  
Robert Rommel ◽  
Ondřej Kotecký ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Volume Fraction ◽  
Fatigue Behavior ◽  
Hysteresis Loss ◽  
Image Correlation ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Volume Strain

This work aimed at studying the effect of a silica specific surface area (SSA), as determined by the nitrogen adsorption method, on the viscoelastic and fatigue behaviors of silica-filled styrene–butadiene rubber (SBR) composites. In particular, silica fillers with an SSA of 125 m2/g, 165 m2/g, and 200 m2/g were selected. Micro-computed X-ray tomography (µCT) was utilized to analyze the 3D morphology of the fillers within an SBR matrix prior to mechanical testing. It was found with this technique that the volume density of the agglomerates drastically decreased with decreasing silica SSA, indicating an increase in the silica dispersion state. The viscoelastic behavior was evaluated by dynamic mechanical analysis (DMA) and hysteresis loss experiments. The fatigue behavior was studied by cyclic tensile loading until rupture enabled the generation of Wöhler curves. Digital image correlation (DIC) was used to evaluate the volume strain upon deformation, whereas µCT was used to evaluate the volume fraction of the fatigue-induced cracks. Last, scanning electron microscopy (SEM) was used to characterize, in detail, crack mechanisms. The main results indicate that fatigue life increased with decreasing silica SSA, which was also accompanied by a decrease in hysteresis loss and storage modulus. SEM investigations showed that filler–matrix debonding and filler fracture were the mechanisms at the origin of crack initiation. Both the volume fraction of the cracks obtained by µCT and the volume strain acquired from the DIC increased with increasing SSA of silica. The results are discussed based on the prominent role of the filler network on the viscoelastic and fatigue damage behaviors of SBR composites.

scholarly journals Setting Relationships between Structure and Devulcanization of Ground Tire Rubber and Their Effect on Self-Healing Elastomers

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 11
Author(s):  
Luis E. Alonso Alonso Pastor ◽  
Karina C. Núñez Núñez Carrero ◽  
Javier Araujo-Morera ◽  
Marianella Hernández Hernández Santana ◽  
José María Pastor
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mechanical Response ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Self Healing ◽  
Tire Rubber ◽  
Great Opportunity ◽  
Ground Tire Rubber

The use of devulcanized tire powder as an effective reinforcement in self-healing styrene-butadiene rubber (SBR) compounds has been investigated for the first time in this work. For this purpose, the evolution of the microstructure of the rubber from end-of-life tires (ELTs) was studied during granulation, grinding and devulcanization through an exhaustive characterization work in order to relate the final microstructure with the mechanical response of the repaired systems. Different morphologies (particle size distribution and specific surface area) obtained by cryogenic and water jet grinding processes, as well as different devulcanization techniques (thermo-mechanical, microwave, and thermo-chemical), were analyzed. The results demonstrated the key influence of the morphology of the ground tire rubber (GTR) on the obtained devulcanized products (dGTR). The predictions of the Horikx curves regarding the selectivity of the applied devulcanization processes were validated, thereby; a model of the microstructure of these materials was defined. This model made it possible to relate the morphology of GTR and dGTR with their activity as reinforcement in self-healing formulations. In this sense, higher specific surface area and percentage of free surface polymeric chains resulted in better mechanical performance and more effective healing. Such a strategy enabled an overall healing efficiency of more than 80% in terms of a real mechanical recovery (tensile strength and elongation at break), when adding 30 phr of dGTR. These results open a great opportunity to find the desired balance between the mechanical properties before and after self-repair, thus providing a high technological valorization to waste tires.

scholarly journals Influence of the Silica Specific Surface Area and Ionic Liquids on the Curing Characteristics and Performance of Styrene–Butadiene Rubber Composites

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5302
Author(s):  
Anna Sowińska-Baranowska ◽  
Magdalena Maciejewska
Keyword(s):  
Ionic Liquids ◽  
Specific Surface ◽  
Surface Area ◽  
Functional Properties ◽  
Specific Surface Area ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Damping Behavior ◽  
And Performance ◽  
Styrene Butadiene

In this work, we present the effect of silica’s specific surface area (180 m2·g−1 and 380 m2·g−1, respectively) on the crosslinking of styrene–butadiene rubber (SBR) composites, as well as their crosslink density and functional properties, such as thermal stability, damping behavior, resistance to thermo-oxidative aging, and tensile properties. Ionic liquids (ILs) with a bromide anion and different cations, i.e., 1-butyl-3-methylimidazolium (Bmi), 1-butyl-3-methylpyrrolidinium (Bmpyr), and 1-butyl-3-methylpiperidinium (Bmpip), were used to enhance the cure characteristics of SBR compounds and the functional properties of SBR vulcanizates. It was proven that apart from the silica’s specific surface area, the filler–polymer and filler–filler physical interactions have a significant impact on the vulcanization kinetics of silica-filled SBR composites. Additionally, the performed studies have shown that ILs positively affected the dispersion of silica’s particles and reduced their ability to form agglomerates in the elastomer matrix, which enhanced the functional properties of the SBR vulcanizates.

scholarly journals Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-Ray Computed Tomography

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1230
Author(s):  
Fabien Léonard ◽  
Zhen Zhang ◽  
Holger Krebs ◽  
Giovanni Bruno
Keyword(s):  
Computed Tomography ◽  
Specific Surface ◽  
Ammonium Nitrate ◽  
Surface Area ◽  
Specific Surface Area ◽  
Volume Fraction ◽  
Fuel Oil ◽  
X Ray ◽  
Oil Retention ◽  
X Ray Computed

The mixture of ammonium nitrate (AN) prills and fuel oil (FO), usually referred to as ANFO, is extensively used in the mining industry as a bulk explosive. One of the major performance predictors of ANFO mixtures is the fuel oil retention, which is itself governed by the complex pore structure of the AN prills. In this study, we present how X-ray computed tomography (XCT), and the associated advanced data processing workflow, can be used to fully characterise the structure and morphology of AN prills. We show that structural parameters such as volume fraction of the different phases and morphological parameters such as specific surface area and shape factor can be reliably extracted from the XCT data, and that there is a good agreement with the measured oil retention values. Importantly, oil retention measurements (qualifying the efficiency of ANFO as explosives) correlate well with the specific surface area determined by XCT. XCT can therefore be employed non-destructively; it can accurately evaluate and characterise porosity in ammonium nitrate prills, and even predict their efficiency.

scholarly journals Effect of Mesopore Development on Butane Working Capacity of Biomass-Derived Activated Carbon for Automobile Canister

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 673
Author(s):  
Byeong-Hoon Lee ◽  
Hye-Min Lee ◽  
Dong Chul Chung ◽  
Byung-Joo Kim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Volume Fraction ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Working Capacity ◽  
Activation Time

Kenaf-derived activated carbons (AKC) were prepared by H3PO4 activation for automobile canisters. The microstructural properties of AKC were observed using Raman spectra and X-ray diffraction. The textural properties were studied using N2/77 K adsorption isotherms. Butane working capacity was determined according to the ASTM D5228. From the results, the specific surface area and total pore volume of the AKC was determined to be 1260–1810 m2/g and 0.68–2.77 cm3/g, respectively. As the activation time increased, the butane activity and retentivity of the AKC increased, and were observed to be from 32.34 to 58.81% and from 3.55 to 10.12%, respectively. The mesopore ratio of activated carbon increased with increasing activation time and was observed up to 78% at 973 K. This indicates that butane activity and retentivity could be a function not only of the specific surface area or total pore volume, but also of the mesopore volume fraction in the range of 2.8–3.8 nm and 5.5-6.5 nm of adsorbents, respectively. The AKC exhibit enhanced butane working capacity compared to commercial activated carbon with the high performance of butane working capacity due to its pore structure having a high mesopore ratio.

Simulated electrical conductivity response of clogging mechanisms for managed aquifer recharge

Geophysics ◽  
2014 ◽  
Vol 79 (2) ◽  
pp. D81-D89 ◽  
Author(s):  
A. Rowan Cockett ◽  
Adam Pidlisecky
Keyword(s):  
Electrical Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Film Growth ◽  
Volume Fraction ◽  
Pore Space ◽  
Managed Aquifer Recharge ◽  
Aquifer Recharge ◽  
Conductive Film

Motivated by the need for improved understanding and monitoring of clogging during managed aquifer recharge, we use numerical experiments to evaluate the effect of three different clogging mechanisms on electrical conductivity (EC), porosity, specific surface area, and electrical tortuosity of a simulated sediment pack. The clogging experiments are designed to simulate effect of clogging due to: (a) addition of finer grains, (b) addition of nonconductive films, and (c) addition of conductive films. The simulations involved starting with a random grain pack of 43% porosity, and subsequently reducing the porosity as would occur during clogging. For each of the experiments, we compute the EC response, specific surface area, and electrical tortuosity across the range of porosities. The differences in EC response between (a) and (b) is minor, however, the sediment parameters measuring pore-space configuration show very different responses (i.e., specific surface area and tortuosity), indicating EC is limited in its sensitivity to specific pore configurations. The results from simulations (a) and (b) are well described by Archie’s equation. For the conductive film experiments (c), we explore the effect of film growth for four different surface conductivities ranging from [Formula: see text] to [Formula: see text]. These conductivities correspond to a range of 5–35 times more conductive than the pore fluid conductivity. The bulk EC signal for each of the films results in a distinct manifestation in terms of measured bulk EC. We fit the EC response of the conductive film experiments with a model based on volume fraction occupied by the film; although the model fit the observed results, we required a unique set of fitting parameters for each Film conductivity.

Modification of Inner Pores with Silicon Carbide Whiskers onto the Al2O3 Substrate by CVI Process

2005 ◽  
Vol 287 ◽  
pp. 212-219 ◽  
Author(s):  
W.S. Park ◽  
Doo Jin Choi ◽  
Hai Doo Kim
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Volume Fraction ◽  
Gas Permeability ◽  
Porous Alumina ◽  
Porous Ceramic ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Particulate Filter

In this study, SiC whiskers were grown in porous alumina substrate in order to enhance the filtering efficiency, performance, and durability by controlling pore morphology. This experiment was performed by chemical vapor infiltration (CVI) in order to obtain the whiskers on the inside of pores as well as on the surface of porous the Al2O3 substrate. The deposition morphology was changed remarkably with the deposition position and temperature. First, the mean diameter of whisker was decreased as the position of observation moved into the inside of substrate due to ‘the depletion effect’ and ‘the pressure effect’. Second, the deposition temperature caused the changes of the deposition type such as debris, whiskers and films and these changes of morphology affect the various properties. When SiC films were deposited, the gas permeability and the specific surface area decreased. However, the whisker showed the opposite result; a large specific surface area provides the absorption site and the whiskers in gas traveling path hinder the particles from easily flowing. Comparing with the normal pores (inter-grain open pores), the pores formed by the whiskers have relatively large volume fraction under the same pore size. Porous ceramic filters with whisker will be expected to increase the filtering efficient and gas permeability simultaneously. It is the main advantage of our whiskered filter. Therefore the porous alumina body which deposited the SiC whisker will be the promising material in order to apply to the particulate filter.

scholarly journals Pitch-Derived Activated Carbon Fibers for Emission Control of Low-Concentration Hydrocarbon

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1313 ◽  
Author(s):  
Hye-Min Lee ◽  
Byeong-Hoon Lee ◽  
Soo-Jin Park ◽  
Kay-Hyeok An ◽  
Byung-Joo Kim
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Fibers ◽  
Pore Volume ◽  
Volume Fraction ◽  
Structural Characteristics ◽  
Total Pore Volume ◽  
Activated Carbon Fibers

The unburned hydrocarbon (HC) emissions of automobiles are subject to strong regulations because they are known to be converted into fine dust, ozone, and photochemical smog. Pitch-based activated carbon fibers (ACF) prepared by steam activation can be a good solution for HC removal. The structural characteristics of ACF were observed using X-ray diffraction. The pore characteristics were investigated using N2/77K adsorption isotherms. The butane working capacity (BWC) was determined according to ASTM D5228. From the results, the specific surface area and total pore volume of the ACF were determined to be 840–2630 m2/g and 0.33–1.34 cm3/g, respectively. The butane activity and butane retentivity of the ACF increased with increasing activation time and were observed to range between 15.78–57.33% and 4.19–11.47%, respectively. This indicates that n-butane adsorption capacity could be a function not only of the specific surface area or total pore volume but also of the sub-mesopore volume fraction in the range of 2.0–2.5 nm of adsorbents. The ACF exhibit enhanced BWC, and especially adsorption velocity, compared to commercial products (granules and pellets), with lower concentrations of n-butane due to a uniformly well-developed pore structure open directly to the outer surface.

scholarly journals MESH FREE ESTIMATION OF THE STRUCTURE MODEL INDEX

2011 ◽  
Vol 28 (3) ◽  
pp. 179 ◽  
Author(s):  
Joachim Ohser ◽  
Claudia Redenbach ◽  
Katja Schladitz
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Volume Fraction ◽  
Structure Model ◽  
Shape Factors ◽  
Closed Set ◽  
Structure Model Index ◽  
Steiner Formula ◽  
Random Closed Set

The structure model index (SMI) is a means of subsuming the topology of a homogeneous random closed set under just one number, similar to the isoperimetric shape factors used for compact sets. Originally, the SMI is defined as a function of volume fraction, specific surface area and first derivative of the specific surface area, where the derivative is defined and computed using a surface meshing. The generalised Steiner formula yields however a derivative of the specific surface area that is – up to a constant – the density of the integral of mean curvature. Consequently, an SMI can be defined without referring to a discretisation and it can be estimated from 3D image data without need to mesh the surface but using the number of occurrences of 2×2×2 pixel configurations, only. Obviously, it is impossible to completely describe a random closed set by one number. In this paper, Boolean models of balls and infinite straight cylinders serve as cautionary examples pointing out the limitations of the SMI. Nevertheless, shape factors like the SMI can be valuable tools for comparing similar structures. This is illustrated on real microstructures of ice, foams, and paper.

scholarly journals Hydrothermal SiO2 Nanopowders: Obtaining Them and Their Characteristics

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 624 ◽  
Author(s):  
Vadim Potapov ◽  
Roman Fediuk ◽  
Denis Gorev
Keyword(s):  
Low Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Volume Fraction ◽  
Spherical Particles ◽  
Orthosilicic Acid ◽  
Amorphous Sio2 ◽  
Vacuum Sublimation ◽  
X Ray

The technological mode of obtaining amorphous SiO2 nanopowders based on hydrothermal solutions is proposed in this study. Polycondensation of orthosilicic acid as well as ultrafiltration membrane separation, and cryochemical vacuum sublimation were used. The characteristics of nanopowders were determined by tunneling electron microscopy, low-temperature nitrogen adsorption, X-ray diffraction, and small-angle X-ray scattering. The scheme allows to adjust density, particle diameters of nanopowders, specific surface area, as well as diameters, area and volume of the pore. Thus, the structure of nanopowders is regulated—the volume fraction of the packing of spherical particles in aggregates and agglomerates, the size of agglomerates, and the number of particles in agglomerates. The pour densities of the nanopowders depend on the SiO2 content in sols, which were 0.02 to 0.3 g/cm3. Nanoparticles specific surface area was brought to 500 m2/g by low temperature polycondensation. Nanoparticle aggregates specific pore volume (0.2–0.3 g/cm3) weakly depend on powders density. The volume fraction of the packing of SiO2 nanoparticles in aggregates was 0.6–0.7. Solid samples of compacted nanopowders had a compressive strength of up to 337 MPa. Possible applications of hydrothermal SiO2 nanopowders are considered.

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