scholarly journals Influence of expanded graphite coming from the electrochemical oxidation of phenol on cement-polymer matrix

2016 ◽  
Vol 18 (4) ◽  
pp. 5-8 ◽  
Author(s):  
Agnieszka Ślosarczyk ◽  
Piotr Krawczyk
Keyword(s):  
Electron Microscopy ◽  
Polymer Network ◽  
Expanded Graphite ◽  
Mechanical Tests ◽  
Flexural Behavior ◽  
Cement Mortars ◽  
Polymer Mortar ◽  
Electro Oxidation ◽  
Oxidation Of Phenol ◽  
Scanning Electron

Abstract In presented article the polymer-modified cement mortars with expanded graphite covered by the oligomer film, being a by-product of phenol electro-oxidation, were investigated. The changes in the morphology of EG and EG/oligomer as well as in the microstructure of cement-polymer composites modified with EG/oligomer were verified using the scanning electron microscopy (SEM). The evaluation of adhesion between EG/oligomer and cement-polymer mortar based on the mechanical tests, especially their flexural behavior. It was shown that the oligomer film formed on EG surface made graphite flakes more durable and resistant to bending. Moreover, the oligomer due to the interaction with polymer network in cement-polymer mortar led to the improvement of flexural toughness of composite.

Preparation of Expanded Graphite Using Recycling Graphite Rods by Microwave Irradiation

2012 ◽  
Vol 610-613 ◽  
pp. 2356-2360
Author(s):  
Hong Liang Hua ◽  
Yun Wang ◽  
Yu Jia Wang ◽  
Shi Jun Ruan ◽  
Chao Zeng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Potassium Dichromate ◽  
Expanded Graphite ◽  
Chemical Oxidation ◽  
Raw Material ◽  
Expandable Graphite ◽  
Graphite Rods ◽  
Scanning Electron

After washing, milling and calcining, the graphite rods recycled from waste dry batteries were used as raw material to prepare expandable graphite by chemical oxidation (using acetic anhydride as inserting and potassium dichromate as oxidant), the expanded graphite was prepared from the obtained expandable graphite by microwave radiation (MW) at 1000W for 60s.The characterization of infrared spectroscopy (IR) and scanning electron microscopy (SEM) of obtained expanded graphite have been discussed. The results show that it is feasible to prepare expanded graphite using graphite rods recycled from waste dry batteries.

scholarly journals Improvement of Mechanical and Rheological Properties of Natural Rubber for Anti-Vibration Applications

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
Nabel K. Abd Ali ◽  
Malia. M. Farhan ◽  
Abbas S . Moosa
Keyword(s):  
Electron Microscopy ◽  
Natural Rubber ◽  
Mechanical Tests ◽  
Friction Resistance ◽  
Synthetic Rubber ◽  
Structure Morphology ◽  
Rheological Test ◽  
Sem Test ◽  
Master Batch ◽  
Scanning Electron

Abstract   This research aims to study and improve the passivating specifications of rubber resistant to  vibration. In this paper, seven different rubber recipes were prepared based on mixtures of natural rubber(NR)  as an essential part in addition to the synthetic rubber (IIR, BRcis, SBR, CR)with different rates. Mechanical tests such as tensile strength, hardness, friction, resistance to compression, fatigue and creep testing in addition to the rheological test were performed. Furthermore, scanning electron microscopy (SEM)test was used to examine the structure morphology of rubber. After studying and analyzing the results, we found that, recipe containing (BRcis) of 40% from the natural rubber has the best mechanical and physical specifications to be used in applications that require the presence of rubber, resistant to vibration. Keywords: Ant vibration behavior , Natural rubber, Synthetic rubber, master batch.

scholarly journals Study of the interface area in the metalo-ceramic prosthetic restorations by Scanning Electron Microscopy (SEM) and EDS Analysis

2019 ◽  
Vol 1 (1) ◽  
pp. 58-59
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oxide Layer ◽  
Mechanical Tests ◽  
Interface Area ◽  
Eds Analysis ◽  
Ceramic Bond ◽  
Metal Ceramic ◽  
Scanning Electron

The research of the metal-ceramic bond and the evaluation of its quality is possible through indirect non-destructive methods, which conclusively complete the mechanical tests to measure the shear resistance. The quality of the restorations in which the chemical adhesion is the mechanism with defining role on the nature of the metal-ceramic bond is achieved mainly by the appearance of an oxide layer formed by the elements in the composition of the alloys. The oxide layer ensures the oxygen bridges, the diffusion of the metal ions into the ceramic mass, the creation of the necessary conditions for the chemical reactions at the metal-ceramic interface. However, the thickness of the oxide layer is an important parameter, which controls the quality of the resistance of the metal-ceramic bond. The analysis of the interface area by scanning electron microscopy (SEM) and the EDS analysis allowed the examination of both components and provided information on the type of rupture when the ceramic was removed from the metallic substrate, the compositional nature in the interface area, the presence of the oxide layer and of its characteristics. The experimental results obtained confirm some results from the literature on the behavior of the noble alloys as substrates in the metal-ceramic restorations.

Preparation and Mechanical Properties of Modified Magnesium Oxysulfate Cement Incorporating Alkali Conditioner

2020 ◽  
Vol 12 (10) ◽  
pp. 1558-1567
Author(s):  
Shengbin Li ◽  
Haoqian Ren ◽  
Qin Wu ◽  
Yiyang Ye
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Mechanical Test ◽  
Mechanical Tests ◽  
Molar Ratio ◽  
Buffer Solution ◽  
Magnesium Oxysulfate ◽  
Scanning Electron

Magnesium oxysulfate cement is an ecological gas-hardening cementitious material. The cement has a complex system, insufficient hydration, and unstable hydration products, so that the cement mechanical property is poor. In this study, calcium chloride/carbon dioxide/weak buffer solution is used to generate alkaline additive, namely vaterite calcium carbonate. The additive material is characterized by scanning electron microscopy and X-ray diffraction, and then the optimal MgO/MgSO4/H2O molar ratio after calcium carbonate is added to magnesium oxysulfate cement, the optimal laying method and reasonable amount of vaterite calcium carbonate are analyzed by mechanical tests. In the experiment, the basic additive is characterized firstly. It is found that the XRD of the additive mainly includes the peaks of calcite and vaterite. It can be seen by scanning electron microscopy that many calcites and vaterites are not formed, the calcites are accumulated more, and there is a large number of particles, which are not appeared before. In the mechanical test of magnesium sulfide cement, the mechanical properties of magnesium oxysulfate cement will increase firstly and then decrease with the increase of MgO/MgSO4 molar ratio in the way of long-cut calcium carbonate for reinforcement. Compared with the layout of long-cut calcium carbonate-magnesium oxysulfate cement, the layout of short-cut calcium carbonate-magnesium oxysulfate cement can enhance the toughness of the modified cement, increase the amount of calcium carbonate, and improve the flexural strength and toughness index of the modified magnesium oxysulfate cement. The blending ratio is better to be 6%. Based on above researches and demonstrations, blending the calcium carbonate-based alkaline additive can effectively improve the mechanical properties of the magnesium oxysulfate cement.

Coupled ZnO/TiO2 Nanorods Deposited in the Pores of Expanded Graphite Prepared by Microwave Irradiation

2011 ◽  
Vol 204-210 ◽  
pp. 268-272
Author(s):  
Min Cong Zhu ◽  
En Qiang Wang ◽  
Ying Chen Zhang ◽  
Deng Xin Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microwave Irradiation ◽  
Expanded Graphite ◽  
Hydrolysis Method ◽  
Catalytic Nanoparticles ◽  
Key Factor ◽  
Temperature And Pressure ◽  
Harsh Conditions ◽  
Scanning Electron

Expanded graphite (EG) was prepared by microwave irradiation at 1000W for 60s. The growth of coupled ZnO/TiO2nanonods in the pores of EG by using hydrolysis method without harsh conditions was investigated and their microstructure was studied by scanning electron microscopy (SEM). Results show that pores of EG, which can load catalytic nanoparticles, is the physical base for growth of catalytic nanorods. The active edges of graphene of freshly EG is a key factor for the growth of coupled ZnO/TiO2nanorods under non-catalytic and normal temperature and pressure conditions.

scholarly journals Thermal Conductivity of Polyimide/Carbon Nanofiller Blends

2007 ◽  
Vol 334-335 ◽  
pp. 749-752 ◽  
Author(s):  
Subrata Ghose ◽  
K.A. Watson ◽  
D.M. Delozier ◽  
D.C. Working ◽  
John W. Connell ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Tensile Testing ◽  
Expanded Graphite ◽  
Multiwalled Carbon ◽  
Carbon Nanofiller ◽  
Scanning Electron

In efforts to improve the thermal conductivity (TC) of Ultem™ 1000, it was compounded with three carbon based nano-fillers. Multiwalled carbon nanotubes (MWCNT), vapor grown carbon nanofibers (CNF) and expanded graphite (EG) were investigated. Ribbons were extruded to form samples in which the nano-fillers were aligned. Samples were fabricated by compression molding where the nano-fillers were randomly oriented. The thermal properties were evaluated by DSC and TGA, and the mechanical properties of the aligned samples were determined by tensile testing. The degree of dispersion and alignment of the nanoparticles were investigated with high-resolution scanning electron microscopy. The thermal conductivity was measured in two directions using the Nanoflash technique.

STRUCTURE AND MECHANICAL CHARACTERISTIC OF CATTLE HORNS

2014 ◽  
Vol 14 (06) ◽  
pp. 1440011 ◽  
Author(s):  
YONG-JUN YU ◽  
MENG ZOU ◽  
SHU-CAI XU ◽  
RONG-RONG ZHANG ◽  
HUI-XIA WANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Characteristics ◽  
Impact Test ◽  
Longitudinal Direction ◽  
Mechanical Tests ◽  
Test Machine ◽  
Light Weight ◽  
Laminated Structure ◽  
Pendulum Impact ◽  
Scanning Electron

In order to investigate the structure and mechanical characteristics of cattle horns, the microstructures of the keratin shell and bone core were examined by scanning electron microscopy, and a series of mechanical tests were performed by the tension-compression test machine and pendulum impact test machine. Results showed that the keratin shell was a laminated structure stacked by keratin protein slices, and the bone core was a light-weight porous material with pores randomly distributed in the longitudinal direction. The ultimate tensile strength of the keratin shell diminished gradually from distal to middle to proximal parts with the values of 162, 125 and 85 MPa, respectively. The ultimate compressive strength of keratin shell and bone core in the longitudinal direction was higher than that in the transverse. The moisture could cut down significantly the mechanical characteristics of keratin shell and bone core. The shock toughness of the keratin shell was 4.9 J/cm2, which was 7 times as large as that of the bone core. It can be concluded that cattle horn is a graded biological material with outstanding mechanical characteristics. The moisture, location and direction of the sampling have a significant effect on the mechanical characteristics of cattle horns. Compared with the bone core, the keratin shell has a better crashworthiness performance.

scholarly journals The Development of Nanoalumina-Based Cement Mortars for Overlay Applications in Concrete Floors

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3465 ◽  
Author(s):  
Szymanowski ◽  
Sadowski
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Aluminum Oxide ◽  
Functional Properties ◽  
Abrasion Resistance ◽  
Cement Mortar ◽  
Cement Mortars ◽  
Positive Effect ◽  
Scanning Electron

This article focuses on the development of nanoalumina-based cement mortars for overlay applications in concrete floors. It focuses on the effect of applying aluminum oxide (Al2O3) nanopowder to the cement mortar used to make the overlay, on the adhesion of this overlay to concrete substrate and on its functional properties. It was claimed that the addition of 0.5% of Al2O3 nanopowder has a positive effect on the adhesion of the cement mortar used to make the overlay to the substrate made of concrete. The prior studies performed using scanning electron microscopy (SEM) confirmed that the reason for the improvement in adhesion is the fact that cement mortar used to make the overlay with the addition of 0.5% of Al2O3 nanopowder is less porous than the reference mortar within the interphase. The article concurs that the most favorable results, in terms of lower abrasion resistance and higher subsurface tensile strength of the cement mortar used to make the overlay, are mainly brought about by adding 0.5% of Al2O3 nanopowder.

Preparation of the EG/TiO2 Composites in the Method of Impregnation

2011 ◽  
Vol 474-476 ◽  
pp. 792-796
Author(s):  
Li Qin Wang ◽  
Xiang Ni Yang ◽  
Xiu Li Zhao ◽  
Rui Jun Zhang ◽  
Yu Lin Yang
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Aqueous Solution ◽  
Scanning Electron Microscopy ◽  
Methyl Orange ◽  
Lamellar Structure ◽  
Expanded Graphite ◽  
X Ray ◽  
Ft Ir ◽  
Scanning Electron

The composites of expanded graphite with TiO2(EG/TiO2) were prepared in the method of impregnation, the morphology and crystal structure were characterized by the means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The decolorization performance of the EG/TiO2composites for the methyl orange aqueous solution were studied. The experimental results were shown as follows: the EG/TiO2composites maintained the porous and lamellar structure of EG, and a lot of anatase TiO2particles as a small lumpdistributed on surfaces and in layers of EG. The composites may contain the graphite both oxidized and un-oxidized, and there was no other organic group left in the composites, except for the functional groups of graphite. Moreover, the EG/TiO2composites had excellent decolorization performance for the methyl orange aqueous solution. When reacted for 90 min, the decolorization rate of the methyl orange aqueous solution was at the peak, up to 96.1%. We supposed that it was mainly due to the interaction between the strong adsorptive ability of EG and the degradation property of TiO2particles.

The Pozzoolanic Activity Level of Powder Waste Glass in Comparisons with other Powders

2015 ◽  
Vol 660 ◽  
pp. 237-243 ◽  
Author(s):  
Ofelia Corbu ◽  
Adrian M. Ioani ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Vasile Meiţă ◽  
Henriette Szilagyi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Glass Powder ◽  
Waste Glass ◽  
Activity Level ◽  
Raw Material ◽  
X Ray ◽  
The Third ◽  
Cement Mortars ◽  
Program Objective ◽  
Scanning Electron

In order to streamline the mixes of concrete with powder waste glass as small as < 0.250 mm, a postdoctoral program objective was to test the activity rate of its pozzoolanic reaction, through various methods and by comparing it with other powders reactions in a standardized cement composition. The first method was to determine the compressive strength of cement mortars, partially substituted by glass powder, silica fume, ash and clay. The second method was determining the chemical composition of the powder with fluorescence X-ray, XRF type. The third method, was based on fragments of mortar studied and subjected to microscopic observations – SEM determination (scanning electron microscopy) to investigate the microstructure of the raw material.

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