scholarly journals A Comparative Study on Structural, Morphological, and Tensile Properties of Binary and Ternary Epoxy Resin-Based Polymer Nanocomposites

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Dalia M. T. Mustafa ◽  
Sarkawt Rostam ◽  
Shujahadeen B. Aziz
Keyword(s):  
Glass Fiber ◽  
Epoxy Resin ◽  
Polymer Nanocomposites ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Calcium Titanate ◽  
X Ray Diffraction ◽  
Fiber Glass ◽  
X Ray ◽  
Good Agreement

In the present work, epoxy resin-based nanocomposites (NCPs) were fabricated with improved mechanical properties. The epoxy resin (EPR) was mixed with differing amounts of calcium titanate (CaTiO3) nanoparticles (NPs) and glass fiber. The results showed that the ternary system contained glass fiber exhibits low mechanical performance compared to binary [EPR:CaTiO3] system. The effect of fiber glass and NPs on the epoxy resin mechanical behavior was determined by conducting a tensile test for various specimen sets. From the mechanical characterizations, it was seen that there is a monotonic relationship between the NPs concentration and Young’s modulus. Additionally, NCPs samples were brittle in nature and the strain rate significantly decreased upon the addition of CaTiO3 concentration; while the tensile strength was increased. From the X-ray diffraction evaluation, it can be concluded that the addition of NPs have a great impact on the epoxy structure. Besides, the morphology appearance was in good agreement with structural and mechanical analysis.

Investigation on the application properties of epoxy resin and glass fiber in RTV mold rubber

e-Polymers ◽  
2016 ◽  
Vol 16 (6) ◽  
pp. 437-445 ◽  
Author(s):  
Yang Siyuan ◽  
Wang Jincheng ◽  
Wang Junhua
Keyword(s):  
Thermal Stability ◽  
Glass Fiber ◽  
Epoxy Resin ◽  
Dimensional Stability ◽  
Room Temperature ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Elongation At Break ◽  
X Ray ◽  
Scanning Electron

AbstractIn this work, epoxy resin (EP), glass fiber (GF), and modified GF (MGF) were used in the modification of room-temperature-vulcanizated (RTV) silicone rubber, and their properties were investigated and characterized. The properties such as tensile strength, elongation at break, dimensional stability, and thermal stability were studied. Results revealed that RTV/EP-3/MGF-3 exhibited the best tensile properties. Meantime, the dimensional stability of these composites was improved in a certain degree. Thermogravimetric (TG) analysis, X-ray diffraction (XRD), scanning electron microscope (SEM), and differential scanning calometry (DSC) were also used in the investigation of the microtopography, structure and properties of these RTV mold rubbers.

Influence of Functionality of Polyhedral Oligomeric Silsesquioxane (POSS) Dispersed in Epoxy Resin for Application in Hybrid Coating

2017 ◽  
Vol 899 ◽  
pp. 278-282 ◽  
Author(s):  
Marielen Longhi ◽  
Vinicius Pistor ◽  
Lucas Pandolphi Zini ◽  
Sandra Raquel Kunst ◽  
Ademir José Zattera
Keyword(s):  
Epoxy Resin ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Xrd Analysis ◽  
Mechanical Analysis ◽  
Diglycidyl Ether ◽  
Hybrid Coating ◽  
X Ray Diffraction ◽  
Characteristic Peak ◽  
X Ray ◽  
Oligomeric Silsesquioxane

The present study aimed to characterize the structure of nanocomposites obtained from the incorporation of three different polyhedral oligomeric silsesquioxane (POSS) in an epoxy resin. glycidylisobutyl-POSS, triglycidylisobutyl-POSS and glycidyl-POSS were added (5% by weight) in an epoxy matrix, diglycidyl ether of bisphenol-A (DGEBA), through a sonication process. The nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and dynamic mechanical analysis (DMA). The XRD analysis presented a characteristic peak of POSS. The incorporation of glycidylisobutyl-POSS showed a significant increase in the value of glass transition temperature (Tg), being also the most effective in terms of dispersion. It should also be noted that glycidyl-POSS presented a greater influence on the thermal stability.

Influence of the Type of Epoxy Resin and Concentration of Glycidylisobutyl-POSS in the Properties of Nanocomposites

2017 ◽  
Vol 25 (8) ◽  
pp. 593-602 ◽  
Author(s):  
Marielen Longhi ◽  
Lucas Pandolphi Zini ◽  
Sandra Raquel Kunst ◽  
Ademir José Zattera
Keyword(s):  
Epoxy Resin ◽  
Mechanical Analysis ◽  
Mechanical Resistance ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
X Ray Diffraction ◽  
Amorphous Halo ◽  
Characteristic Peak ◽  
X Ray ◽  
Hydrophilic Behavior ◽  
Hydroxyl Band

Epoxy resin is one of the most used resins for obtaining composites and coatings. Its properties have been modified using many materials, mainly based on nanotechnology, such as clays and polyhedral oligomeric silsesquioxanes (POSS). POSS may increase thermal and mechanical resistance and hydrophobicity of the epoxy resin. This study aims at characterizing epoxy nanocomposites, using two distinct resins (DGEBA and DGEBF) and an addition of glycidylisobutyl-POSS in contents of 2.5% and 5% (w/w), through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Samples showed an amorphous halo due to the epoxy resin and a characteristic peak of POSS. TGA results showed a greater residual mass in DGEBF systems due to its wider formation of crosslinks. FTIR spectra demonstrated a higher amplitude of the hydroxyl band in DGEBF 5% system, which may affect its hydrophilic behavior because of the molecular mobility and resin weight reduction. DMA results showed that DGEBA systems are more flexible than DGEBF.

scholarly journals The Potential for Natural Stones from Northeastern Brazil to Be Used in Civil Construction

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 440
Author(s):  
Fabiana Pereira da Costa ◽  
Jucielle Veras Fernandes ◽  
Luiz Ronaldo Lisboa de Melo ◽  
Alisson Mendes Rodrigues ◽  
Romualdo Rodrigues Menezes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Resistance ◽  
Mechanical Analysis ◽  
Northeastern Brazil ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Agents ◽  
Natural Stones

Natural stones (limestones, granites, and marble) from mines located in northeastern Brazil were investigated to discover their potential for use in civil construction. The natural stones were characterized by chemical analysis, X-ray diffraction, differential thermal analysis, and optical microscopy. The physical-mechanical properties (apparent density, porosity, water absorption, compressive and flexural strength, impact, and abrasion) and chemical resistance properties were also evaluated. The results of the physical-mechanical analysis indicated that the natural stones investigated have the potential to be used in different environments (interior, exterior), taking into account factors such as people’s circulation and exposure to chemical agents.

scholarly journals Functional Bionanocomposite Fibers of Chitosan Filled with Cellulose Nanofibers Obtained by Gel Spinning

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1563
Author(s):  
Sofia Marquez-Bravo ◽  
Ingo Doench ◽  
Pamela Molina ◽  
Flor Estefany Bentley ◽  
Arnaud Kamdem Tamo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Cellulose Nanofibers ◽  
Microstructural Characterization ◽  
Fiber Formation ◽  
Fiber Direction ◽  
Composite Fibers ◽  
X Ray Diffraction ◽  
Gel Spinning ◽  
X Ray

Extremely high mechanical performance spun bionanocomposite fibers of chitosan (CHI), and cellulose nanofibers (CNFs) were successfully achieved by gel spinning of CHI aqueous viscous formulations filled with CNFs. The microstructural characterization of the fibers by X-ray diffraction revealed the crystallization of the CHI polymer chains into anhydrous chitosan allomorph. The spinning process combining acidic–basic–neutralization–stretching–drying steps allowed obtaining CHI/CNF composite fibers of high crystallinity, with enhanced effect at incorporating the CNFs. Chitosan crystallization seems to be promoted by the presence of cellulose nanofibers, serving as nucleation sites for the growing of CHI crystals. Moreover, the preferential orientation of both CNFs and CHI crystals along the spun fiber direction was revealed in the two-dimensional X-ray diffraction patterns. By increasing the CNF amount up to the optimum concentration of 0.4 wt % in the viscous CHI/CNF collodion, Young’s modulus of the spun fibers significantly increased up to 8 GPa. Similarly, the stress at break and the yield stress drastically increased from 115 to 163 MPa, and from 67 to 119 MPa, respectively, by adding only 0.4 wt % of CNFs into a collodion solution containing 4 wt % of chitosan. The toughness of the CHI-based fibers thereby increased from 5 to 9 MJ.m−3. For higher CNFs contents like 0.5 wt %, the high mechanical performance of the CHI/CNF composite fibers was still observed, but with a slight worsening of the mechanical parameters, which may be related to a minor disruption of the CHI matrix hydrogel network constituting the collodion and gel fiber, as precursor state for the dry fiber formation. Finally, the rheological behavior observed for the different CHI/CNF viscous collodions and the obtained structural, thermal and mechanical properties results revealed an optimum matrix/filler compatibility and interface when adding 0.4 wt % of nanofibrillated cellulose (CNF) into 4 wt % CHI formulations, yielding functional bionanocomposite fibers of outstanding mechanical properties.

A DFT study of spherands containing five anisyl groups — Highly preorganized to bind the alkali metal

2006 ◽  
Vol 84 (8) ◽  
pp. 1045-1049 ◽  
Author(s):  
Shabaan AK Elroby ◽  
Kyu Hwan Lee ◽  
Seung Joo Cho ◽  
Alan Hinchliffe
Keyword(s):  
Density Functional Theory ◽  
Binding Energy ◽  
Density Functional ◽  
Ionic Radius ◽  
Binding Energies ◽  
Cavity Size ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Good Agreement

Although anisyl units are basically poor ligands for metal ions, the rigid placements of their oxygens during synthesis rather than during complexation are undoubtedly responsible for the enhanced binding and selectivity of the spherand. We used standard B3LYP/6-31G** (5d) density functional theory (DFT) to investigate the complexation between spherands containing five anisyl groups, with CH2–O–CH2 (2) and CH2–S–CH2 (3) units in an 18-membered macrocyclic ring, and the cationic guests (Li+, Na+, and K+). Our geometric structure results for spherands 1, 2, and 3 are in good agreement with the previously reported X-ray diffraction data. The absolute values of the binding energy of all the spherands are inversely proportional to the ionic radius of the guests. The results, taken as a whole, show that replacement of one anisyl group by CH2–O–CH2 (2) and CH2–S–CH2 (3) makes the cavity bigger and less preorganized. In addition, both the binding and specificity decrease for small ions. The spherands 2 and 3 appear beautifully preorganized to bind all guests, so it is not surprising that their binding energies are close to the parent spherand 1. Interestingly, there is a clear linear relation between the radius of the cavity and the binding energy (R2 = 0.999).Key words: spherands, preorganization, density functional theory, binding energy, cavity size.

scholarly journals Synthesis and Characterization of Clay Polymer Nanocomposites of P(4VP-co-AAm) and Their Application for the Removal of Atrazine

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 721 ◽  
Author(s):  
Jorge A. Ramírez-Gómez ◽  
Javier Illescas ◽  
María del Carmen Díaz-Nava ◽  
Claudia Muro-Urista ◽  
Sonia Martínez-Gallegos ◽  
...  
Keyword(s):  
Polymer Nanocomposites ◽  
Nanocomposite Materials ◽  
Synthesis And Characterization ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
Numerous Species ◽  
X Ray ◽  
Different Types ◽  
Synthesized Materials

Atrazine (ATZ) is an herbicide which is applied to the soil, and its mechanism of action involves the inhibition of photosynthesis. One of its main functions is to control the appearance of weeds in crops, primarily in corn, sorghum, sugar cane, and wheat; however, it is very toxic for numerous species, including humans. Therefore, this work deals with the adsorption of ATZ from aqueous solutions using nanocomposite materials, synthesized with two different types of organo-modified clays. Those were obtained by the free radical polymerization of 4-vinylpyridine (4VP) and acrylamide (AAm) in different stoichiometric ratios, using tetrabutylphosphonium persulfate (TBPPS) as a radical initiator and N,N′-methylenebisacrylamide (BIS) as cross-linking agent. The structural, morphological, and textural characteristics of clays, copolymers, and nanocomposites were determined through different analytical and instrumental techniques, i.e., X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Adsorption kinetics experiments of ATZ were determined with the modified and synthesized materials, and the effect of the ratio between 4VP and AAm moieties on the removal capacities of the obtained nanocomposites was evaluated. Finally, from these sets of experiments, it was demonstrated that the synthesized nanocomposites with higher molar fractions of 4VP obtained the highest removal percentages of ATZ.

Local atomic structure in tetragonal pure ZrO2nanopowders

2010 ◽  
Vol 43 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Leandro M. Acuña ◽  
Diego G. Lamas ◽  
Rodolfo O. Fuentes ◽  
Ismael O. Fábregas ◽  
Márcia C. A. Fantini ◽  
...  
Keyword(s):  
Tetragonal Phase ◽  
Local Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Structures ◽  
Crystallite Sizes ◽  
Exafs Study ◽  
The Difference ◽  
X Ray Absorption ◽  
Good Agreement

The local atomic structures around the Zr atom of pure (undoped) ZrO2nanopowders with different average crystallite sizes, ranging from 7 to 40 nm, have been investigated. The nanopowders were synthesized by different wet-chemical routes, but all exhibit the high-temperature tetragonal phase stabilized at room temperature, as established by synchrotron radiation X-ray diffraction. The extended X-ray absorption fine structure (EXAFS) technique was applied to analyze the local structure around the Zr atoms. Several authors have studied this system using the EXAFS technique without obtaining a good agreement between crystallographic and EXAFS data. In this work, it is shown that the local structure of ZrO2nanopowders can be described by a model consisting of two oxygen subshells (4 + 4 atoms) with different Zr—O distances, in agreement with those independently determined by X-ray diffraction. However, the EXAFS study shows that the second oxygen subshell exhibits a Debye–Waller (DW) parameter much higher than that of the first oxygen subshell, a result that cannot be explained by the crystallographic model accepted for the tetragonal phase of zirconia-based materials. However, as proposed by other authors, the difference in the DW parameters between the two oxygen subshells around the Zr atoms can be explained by the existence of oxygen displacements perpendicular to thezdirection; these mainly affect the second oxygen subshell because of the directional character of the EXAFS DW parameter, in contradiction to the crystallographic value. It is also established that this model is similar to another model having three oxygen subshells, with a 4 + 2 + 2 distribution of atoms, with only one DW parameter for all oxygen subshells. Both models are in good agreement with the crystal structure determined by X-ray diffraction experiments.

Investigation of Residual Strains of the Second Kind in Plastically Deformed Metallic Materials

1994 ◽  
Vol 376 ◽  
Author(s):  
M. Vrána ◽  
P. Klimanek ◽  
T. Kschidock ◽  
P. Lukáš ◽  
P. Mikula
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Stacking Faults ◽  
Metallic Materials ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Diffractometer ◽  
Residual Strains ◽  
Good Agreement

ABSTRACTInvestigation of strongly distorted crystal structures caused by dislocations, stacking-faults etc. in both plastically deformed f.c.c. and b.c.c. metallic materials was performed by the analysis of the neutron diffraction line broadening. Measurements were realized by means of the high resolution triple-axis neutron diffractometer equipped by bent Si perfect crystals as monochromator and analyzer at the NPI Řež. The substructure parameters obtained in this manner are in good agreement with the results of X-ray diffraction analysis.

Structural Properties Of Co/Re Superlattices

1991 ◽  
Vol 238 ◽  
Author(s):  
Y. Huai ◽  
R. W. Cochrane ◽  
Y. Shi ◽  
H. E. Fischer ◽  
M. Sutton
Keyword(s):  
Structural Disorder ◽  
Multilayer Films ◽  
Film Plane ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bilayer Films ◽  
Out Of Plane ◽  
Reflectivity Data ◽  
Sharp Interfaces ◽  
Good Agreement

ABSTRACTThe structures of equal-thickness Co/Re multilayer films and several Co/Re bilayer films have been investigated by X-ray diffraction at low and high angles. Analysis of low-angle reflectivity data from bilayer films indicates that interfacial intermixing is limited to three monolayers and that the two interfacial configurations are different. The high-angle X-ray diffraction data show that multilayer films have coherent interfaces and a highly textured structure with hep [002] orientations normal to the film plane for periods 21 Å ≤ Λ ≤220 Å. Detailed structures have been determined by fitting the X-ray spectra to calculated ones using a trapezoidal model. The results indicate that samples with 42 Å≤ Λ ≤220 Å have relatively sharp interfaces, in good agreement with the bilayer results. In addition, an out-of-plane expansion of the Co (002) layer is observed in samples with large Λ and results from structural disorder leading to a reduced atomic density. For Λ <21 Å the interfaces arise from the rougher surfaces of the deposited layers.

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