Design of Novel Treated Silica Xerogels: Synthesis, Property and Reinforcement in Silicone Elastomers

1998 ◽  
Vol 520 ◽  
Author(s):  
Q. Deng ◽  
G. T. Bums ◽  
J. R. Hahn ◽  
C. C. Reese ◽  
J. D. Preston ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Area ◽  
Silica Xerogels ◽  
Silicone Elastomers ◽  
Surface Areas ◽  
Reinforcing Fillers ◽  
Controlled Porosity ◽  
The Relationship ◽  
Filler Structure

ABSTRACTTreated silica xerogels with controlled porosity and surface area were prepared by the in-situ treatment of hydrogels with hexamethyldisiloxane in the presence of isopropyl alcohol. The resulting hydrogels were hydrophobic and readily transferred to organic solvents allowing their isolation. The surface area and porosity of the xerogel were controlled by varying the pH, time and temperature used to aggregate the hydrogel prior to treatment. The treated xerogels were evaluated as reinforcing fillers in silicone rubber formulations. When the bases were crosslinked with peroxides, silicone elastomers with acceptable mechanical properties were obtained. The relationship between the surface area, porosity and the type and degree of surface treatment of the xerogel, and its reinforcing ability was studied. In general, the mechanical properties of the elastomer increased as the filler structure increased; however, xerogels with higher surface areas were more difficult to incorporate and gave higher plasticity bases.

Effects of Particle Size and Size Distribution on the Mechanical Properties of EPDM/Silica Vulcanizates

2008 ◽  
Vol 47-50 ◽  
pp. 113-116 ◽  
Author(s):  
M.N. Ichazo ◽  
C. Albano ◽  
M. Hernández ◽  
J. González ◽  
A. Carta
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Size Distribution ◽  
Surface Area ◽  
Bimodal Distribution ◽  
Epdm Rubber ◽  
Surface Areas ◽  
Precipitated Silica ◽  
Internal Mixer ◽  
Tear Properties

In this work we present the influence of different particle size (surface areas: 120,150, 200 and 250 m2/g) and size distribution of precipitated silica on the mechanical properties of Ethylene- Propylene-Diene (EPDM) rubber. The vulcanization system employed was efficient. Compounds were prepared using a Banbury internal mixer. Tensile and tear properties of vulcanized blends were determined according to ASTM D412 and ASTM D624 procedures, respectively. Results show an increasing tendency on tensile properties when particle size decreases, due to the better dispersion of the filler and to a greater interaction with the rubber. Increases of up to 500% on tensile strength and 400% on tear strength were observed. However, there was an incoherent behavior for the silica with surface area of 200 m2/g (Si-200), so size distribution of the aggregates was experimentally determined by a microphotography study. Secondary aggregates size distribution was very different for each type of silica. Aggregates for Si-200 presented a bimodal distribution where the greater frequencies correspond to aggregates with surface area higher than the corresponding values for the Si-120. This fact could explain why the mechanical properties of the EPDM filled with Si-200 are not in between the values of the compounds filled with Si-150 and Si-250.

The Influence of Spraying Parameters on Stresses and Mechanical Properties of HVOF-Sprayed Co-Cr-W-C Coatings

2014 ◽  
Vol 606 ◽  
pp. 171-174 ◽  
Author(s):  
Jiří Matějíček ◽  
Šárka Houdková ◽  
Olga Bláhová ◽  
Zdenek Pala
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Particle Temperature ◽  
Instrumented Indentation ◽  
Stellite 6 ◽  
Young’S Moduli ◽  
Particle Characteristics ◽  
Spraying Parameters ◽  
The Relationship

Stellite 6 Co-Cr-W-C coatings were sprayed by HVOF while systematically varying the spraying parameters, namely the equivalent ratio and combustion pressure. During spraying, the in-flight particle temperature and velocity were measured. Deposition, thermal and residual stresses were determined by in-situ curvature monitoring of the sprayed samples. Young's moduli and hardness of the coatings were determined by instrumented indentation. The relationship between spraying parameters, in-flight particle characteristics and mechanical properties is discussed.

Fabrication of Ti2AlC/TiAl Composites with the Addition of Niobium by Spark Plasma Sintering

2008 ◽  
Vol 368-372 ◽  
pp. 1004-1006 ◽  
Author(s):  
Yun Long Yue ◽  
H.T. Wu
Keyword(s):  
Mechanical Properties ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Three Point Bending ◽  
Plasma Sintering ◽  
Titanium Aluminum ◽  
Spark Plasma ◽  
The Difference ◽  
The Relationship

Ti2AlC/TiAl composites with the addition of niobium were prepared by spark plasma sintering using titanium, aluminum, niobium elemental powers and TiC particles as reactants. The experimental and analytical studies on this kind of material concentrated on the relationship between reinforcement phase and mechanical properties. The Ti2AlC/TiAl composites with 5% niobium exhibit high mechanical properties. The three-point bending strength and fracture toughness reaches as high as 915MPa and 23 MPa·m1/2, respectively. It is found that the in-situ reaction occurs at 1100°C with the addition of niobium at the interface between the TiAl matrix and original reinforcement TiC. Further XRD results indicate that the difference in the reinforcement phase from TiC to Ti2AlC is one of the most important origins to the variation in mechanical properties.

The relationship between air temperature, scrotal surface area and testis temperature in rams

1969 ◽  
Vol 9 (38) ◽  
pp. 258 ◽  
Author(s):  
DG Fowler
Keyword(s):  
Surface Area ◽  
Air Temperature ◽  
Sweat Loss ◽  
Surface Areas ◽  
Air Temperatures ◽  
Skin Fold ◽  
Low Degree ◽  
Important Means ◽  
High Degree ◽  
The Relationship

Scrotal surface area, intra-testicular, and subcutaneous scrotal temperatures were measured for five Merino rams selected for a high degree of skin fold (Folds Plus) and five selected for a low degree of skin fold (Folds Minus) at air temperatures between 20�C and 45�C. As air temperature increased, scrotal surface area of both Folds Plus and Folds Minus rams increased slightly. The greatest increases occurred at a scrotal temperature of about 36�C. At all temperatures Folds Plus rams had more pendulous scrota and larger scrotal surface areas than Folds Minus rams. Despite this, the intra-testicular temperatures of Folds Plus rams were higher than those of Folds Minus. Increasing scrotal surface area at high temperatures is one means of reducing testes temperature and maintaining fertility, but the scrotum has other more important means of thermoregulation, e.g., rate and amount of sweat loss.

Mechanical properties of illite‐based ceramics with controlled porosity studied by modern in situ techniques

2019 ◽  
Vol 103 (4) ◽  
pp. 2780-2790
Author(s):  
Michal Knapek ◽  
Jakub Kušnír ◽  
Tomáš Húlan ◽  
Peter Minárik ◽  
Štefan Csáki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
In Situ Techniques ◽  
Controlled Porosity

scholarly journals Joining Alumina and Sapphire by Growing Aluminium Borate Whiskers In-Situ, and the Whiskers’ Orientation Relationship with the Sapphire Substrate

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 175 ◽  
Author(s):  
Chun Li ◽  
Xiaoqing Si ◽  
Shuang Wu ◽  
Junlei Qi ◽  
Yongxian Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Orientation Relationship ◽  
Sapphire Substrate ◽  
Great Influence ◽  
The Other ◽  
Aluminium Borate ◽  
Random Growth ◽  
The Relationship ◽  
Scanning Electron

Bonding between polycrystal alumina and sapphire with (0001), (10 1 ¯ 0), (11 2 ¯ 0), (1 1 ¯ 02) orientations is successfully achieved by growing aluminium borate whiskers in the joint. The morphology of the whiskers in the joint is characterised by (Scanning Electron Microscopy) SEM. The relationship between the growing direction of the aluminium borate whiskers and the orientation of the sapphire substrate is investigated. The effect of the growing direction of the aluminium borate whiskers on the mechanical properties of the joint is discussed. The results show that the whiskers on the sapphire with (10 1 ¯ 0) orientation grow perpendicular to the surface of the substrate while the whiskers show a random growth on the other substrates. It is found that there is an orientation relationship between the whiskers (220) and sapphire (10 1 ¯ 0) and the morphology of the whiskers has great influence on the mechanical properties of the joint. The joint between polycrystal alumina and sapphire with (10 1 ¯ 0) orientation exhibits the highest strength, which reaches 26 MPa.

Tuning the mechanical properties of MgO filled epichlorohydrin elastomer composites through in-situ alteration of filler structure using water as stimulus

2021 ◽  
Vol 26 ◽  
pp. 102116
Author(s):  
Jeevanandham Neethirajan ◽  
Tamil Selvan Natarajan ◽  
Sven Wiessner ◽  
Kinsuk Naskar ◽  
Amit Das
Keyword(s):  
Mechanical Properties ◽  
Elastomer Composites ◽  
Filler Structure

scholarly journals Experimental study of shale drillability with different bedding inclinations under varying wellbore pressure conditions

2021 ◽  
Vol 11 (4) ◽  
pp. 1751-1759
Author(s):  
Shuai Chen ◽  
Xiangchao Shi ◽  
Heng Bao ◽  
Leiyu Gao ◽  
Jie Wu
Keyword(s):  
Mechanical Properties ◽  
Shale Gas ◽  
Physical And Mechanical Properties ◽  
In Situ Conditions ◽  
Wellbore Pressure ◽  
Development Engineering ◽  
The Impact ◽  
The Relationship ◽  
Insight Into

AbstractIn the practice of shale gas development engineering, it is important to understand the physical and mechanical properties of shale. The bedding inclinations of shale are known to significantly influence its physical and mechanical properties. This study mainly examined the influence of bedding inclinations on drillability under different wellbore pressures. The bedding inclinations used in this study varied from 0° to 90°, with a gradient of 15°. The wellbore pressure values used varied from 0 to 25 MPa, with a gradient of 5 MPa. The results show that the drillability index of shale increases exponentially with increasing wellbore pressure at different bedding inclinations. The proposed exponential empirical model can describe the relationship between the drillability index and wellbore pressure. When the wellbore pressure is less than 15 MPa, bedding inclinations significantly influence the drillability index, and the drillability index of shale shows a “W”-type variation trend as the bedding inclinations increase in the range of 0° to 90°. The influence of bedding inclinations on drillability decreases gradually with increasing wellbore pressure. When the wellbore pressure increases to 25 MPa, the impact of bedding inclinations on drillability is virtually undetectable. The results of this study can provide reasonably insight into the effect of bedding inclinations on shale deformation under the drill bit, and useful prediction for the drillability index under in situ conditions.

scholarly journals Investigation of Mechanical Properties of Low-Density Polyethylene with Copper Nanoparticles

2021 ◽  
Vol 15 ◽  
pp. 181-188
Author(s):  
M. V. Klychnikova ◽  
Kyaw Ye Ko
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Filler Content ◽  
Physical And Mechanical Properties ◽  
Ex Situ ◽  
Flow State ◽  
In Situ Preparation ◽  
The Matrix ◽  
The Relationship

In this work, it is shown that the method of the in situ preparation of Cu/LLDPE by combining the formation of a composite and a nanodispersed phase in the viscous-flow state of a polymer makes it possible to achieve a uniform distribution of nanoparticles in the matrix and effectively regulate their mechanical and functional properties. The optimal concentration of Cu nanofiller was found to be 2-5%, allowing to achieve the best mechanical properties. Comparative analysis of the physical and mechanical properties of Cu/LLDPE nanocomposites obtained by various methods shows that the deformation and strength characteristics of the 3CuLLDPE nanocomposite obtained by the in situ method are improved in comparison with the properties of the 3CuLLDPE nanocomposite, prepared by ex situ method. The relationship between the filler content and the modulus of elasticity/tensile strength has been determined. With an increase in the filler content, the elastic modulus increases by 10-20%, and the tensile strength decreases by 30%. Elongation at break for samples with nanofiller content up to 3 wt. % higher than unfilled polymer

scholarly journals Influence of polyvinyl alcohol amount on producing in situ photo-crosslinked thioamide functionalized nanofiber membranes

2015 ◽  
Vol 80 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Bihter Zeytuncu ◽  
Mehmet Morcali ◽  
Suleyman Akman ◽  
Onuralp Yucel
Keyword(s):  
Surface Area ◽  
Poly Vinyl Alcohol ◽  
Electrospinning Technique ◽  
Durability Test ◽  
Average Mass ◽  
Water Durability ◽  
Surface Areas ◽  
Bet Analysis ◽  
Nanofiber Membranes

Poly(vinyl alcohol)/maleic anhydride/acryloyl thioamide monomer (PVA/MA/ATM) photo-cured nanofiber membranes and pure PVA nanofiber membranes were produced by electrospinning technique. In situ UV radiation was applied during the electrospinning in order to provide polymerization during the jet flight and promote crosslinking of ATM and MA with PVA. The cross-linking was examined by Fourier-transform infrared spectroscopy (FTIR). The morphology and thermal behavior of electrospun nanofiber were characterized by scanning electron microscope (SEM) and thermogravimetric analysis (TGA), respectively. The surface area of nanofiber membranes was measured by Brunauer-Emmert-Teller (BET) analysis. Furthermore, water durability test was examined. Water durability test demonstrated that in situ photo-cured PVA/MA/ATM nanofiber membrane had the least average mass loss. The surface areas of PVA/MA/ATM nanofiber membranes were 160-280 m2/g. The surface area and diameter of PVA/MA/ATM nanofibers decreased as the PVA content increased. The diameter of nanofibers was obtained less than 100 nm. The results showed that the water-insoluble nanofiber membranes with better chemical and thermal resistance were obtained. These nanofiber membranes may be a promising candidate for the usage of water treatment.

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