scholarly journals Improving heat aging and mechanical properties of fluoroelastomer using carbon nanotubes

2017 ◽  
Vol 19 (1) ◽  
pp. 132-142 ◽  
Author(s):  
Javad Heidarian ◽  
Aziz Hassan
Keyword(s):  
Crystal Size ◽  
Xrd Analysis ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Elongation At Break ◽  
X Ray ◽  
Before And After ◽  
The Degree Of Crystallinity ◽  
Stress Induced Crystallization ◽  
Induced Crystallization

Abstract Carbon nanotube (CNT)-, carbon black (CB)-filled fluoroelastomer (FE) and unfilled-FE compounds were prepared (CNT/FE, CB/FE and FE). The compounds were subjected to heat air aging and characterized by tensile test and X-Ray Diffraction (XRD) analysis. Results show that CNT improved tensile properties of FE before and after aging. All samples show stress induced crystallization (SIC) during tension. XRD results show that under all conditions, the crystals were in the form of γ-phase. For both aged and un-aged specimens, the degree of crystallinity (Xc) is low. After tensile stretching, Xc of un-aged specimens increases tremendously, with larger crystal size. Under the same conditions, the order of elongation at break (EL) was FE > CB/FE > CNT/FE. Normal modulus (NM) and tangent modulus (TM) at the same conditions was in the order of CNT/FE > CB/FE > FE. Tensile strength had the order of CNT/FE > CB/FE > FE.

scholarly journals Ostrich eggshell as calcium source for the synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc

Cerâmica ◽  
2016 ◽  
Vol 62 (364) ◽  
pp. 386-391 ◽  
Author(s):  
J. R. M. Ferreira ◽  
L. H. L. Louro ◽  
A. M. Costa ◽  
J. B. de Campos ◽  
M. H. Prado da Silva
Keyword(s):  
Xrd Analysis ◽  
Quantitative Chemical Analysis ◽  
X Ray Diffraction ◽  
Spectroscopy Technique ◽  
X Ray ◽  
Heat Treated ◽  
Before And After ◽  
Calcium Source ◽  
The Fourier Transform ◽  
Ostrich Eggshell

Abstract In the present study, hydroxyapatite and Zn-substituted hydroxyapatite powders were synthesized using ostrich eggshell as a calcium source. The samples were analyzed by scanning electron microscopy with field emission gun, and X-ray diffraction (XRD) to identify the present phases, and X-ray fluorescence spectroscopy for quantitative chemical analysis of the synthesized and heat treated powders. The Fourier transform infrared spectroscopy technique was used before and after heat treatments at 700, 900 and 1100 °C in order to identify the functional groups present, as an additional technique to the XRD analysis. The results presented in this study represent a promising method for synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc, since the results showed no undesirable phases or impurities in the produced powders. It was observed that Zn-substituted hydroxyapatite showed higher thermal stability, when compared to pure hydroxyapatite.

scholarly journals Hemp Fibre Reinforced Poly(Lactic Acid) Composites

2007 ◽  
Vol 29-30 ◽  
pp. 337-340 ◽  
Author(s):  
M.A. Sawpan ◽  
K.L. Pickering ◽  
Alan Fernyhough
Keyword(s):  
Lactic Acid ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hemp Fibre ◽  
Reinforcing Material ◽  
Fibre Loading ◽  
The Degree Of Crystallinity

The potential of hemp fibre as a reinforcing material for Poly(lactic acid) (PLA) was investigated. Good interaction between hemp fibre and PLA resulted in increases of 100% for Young’s modulus and 30% for tensile strength of composites containing 30 wt% fibre. Different predictive ‘rule of mixtures’ models (e.g. Parallel, Series and Hirsch) were assessed regarding the dependence of tensile properties on fibre loading. Limited agreement with models was observed. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) studies showed that hemp fibre increased the degree of crystallinity in PLA composites.

Study of the structure and thermal characteristics of nanocomposites based on polyvinyl alcohol and intercalated montmorillonite

2019 ◽  
pp. 089270571987919
Author(s):  
Volodymyr Krasinskyi ◽  
Ivan Gajdos ◽  
Oleh Suberlyak ◽  
Viktoria Antoniuk ◽  
Tomasz Jachowicz
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Acrylic Acid ◽  
Polyvinyl Alcohol ◽  
Thermal Characteristics ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Degree Of Crystallinity

The structure and thermal characteristics of nanocomposites based on polyvinyl alcohol (PVA) and montmorillonite (MMT) intercalated with polyvinylpyrrolidone were investigated by X-ray diffraction analysis and differential scanning calorimetry. The modification of PVA with intercalated MMT reduces the degree of crystallinity of the resulting nanocomposites but significantly increases their thermal stability. Under ultrasound, the intercalated MMT was completely distributed in a PVA solution and formed a monocrystalline structure. Films based on PVA with modified MMT were cross-linked at 110°C in the presence of 5 wt% acrylic acid and 0.5 wt% Ferrous(II) sulfate as an initiator. The formed films have a homogeneous cross-linked structure.

Polysilicon Films Formed on Metal Sheets by Aluminium Induced Crystallization of Amorphous Silicon: Barrier Effect

2009 ◽  
Vol 1153 ◽  
Author(s):  
Prathap Pathi ◽  
Ozge Tüzün ◽  
Abdelilah Slaoui
Keyword(s):  
Amorphous Silicon ◽  
Electron Beam Evaporation ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coated Metal ◽  
Metal Sheets ◽  
Different Temperatures ◽  
Si Films ◽  
Induced Crystallization

AbstractPolycrystalline silicon (pc-Si) thin films have been synthesized by aluminium induced crystallization (AIC) of amorphous silicon (a-Si) at low temperatures (≤500°C) on flexible metallic substrates for the first time. Different diffusion barrier layers were used to prepare stress free pc-Si films as well as to evaluate the effective barrier against substrate impurity diffusion. The layers of aluminum (Al) and then amorphous silicon with the thickness of 0.27 μm and 0.37 μm were deposited on barrier coated metal sheets by means of an electron beam evaporation and PECVD, respectively. The bi-layers were annealed in a tube furnace at different temperatures (400-500°C) under nitrogen flow for different time periods (1-10hours). The degree of crystallinity of the as-grown layers was monitored by micro-Raman and reflectance spectroscopies. Structure, surface morphology and impurity analysis were carried out by X-ray diffraction, scanning electron microscopy (SEM) and EDAX, respectively. The X-ray diffraction measurements were used to determine the orientation of grains. The results show that the AIC films on metal sheets are polycrystalline and the grains oriented in (100) direction preferentially. However, the properties of AIC films are highly sensitive to the surface roughness.

scholarly journals Determination of the Degree of Crystallinity of Poly(2-methyl-2-oxazoline)

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4356
Author(s):  
Evgeniy M. Chistyakov ◽  
Sergey N. Filatov ◽  
Elena A. Sulyanova ◽  
Vladimir V. Volkov
Keyword(s):  
Thermal Destruction ◽  
Polymer Melt ◽  
Boron Trifluoride Etherate ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Cationic Ring Opening Polymerization ◽  
The Degree Of Crystallinity

A new method for purification of 2-methyl-2-oxazoline using citric acid was developed and living cationic ring-opening polymerization of 2-methyl-2-oxazoline was carried out. Polymerization was conducted in acetonitrile using benzyl chloride—boron trifluoride etherate initiating system. According to DSC data, the temperature range of melting of the crystalline phase of the resulting polymer was 95–180 °C. According to small-angle X-ray scattering and wide-angle X-ray diffraction data, the degree of crystallinity of the polymer was 12%. Upon cooling of the polymer melt, the polymer became amorphous. Using thermogravimetric analysis, it was found that the thermal destruction of poly(2-methyl-2-oxazoline) started above 209 °C.

scholarly journals Microwave-Assisted Preparation of Zinc-Doped β-Tricalcium Phosphate for Orthopedic Applications

2020 ◽  
Author(s):  
Ali Taha Saleh ◽  
Dheyaa Alameri
Keyword(s):  
Tricalcium Phosphate ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted ◽  
Ftir Spectrometer ◽  
Diffraction Peaks ◽  
Orthopedic Applications ◽  
The Degree Of Crystallinity ◽  
Good Agreement

A novel two-step methodology delivering zinc into the structure of β-tricalcium phosphate (β-TCP) has been investigated. Incorporating wet precipitation of calcium-deficient apatite [Ca9-xZnx(HPO4)(PO4)5(OH)] (x = 0.00–1.00 mol) using a microwave-assisted process followed by two-hour calcination at 1000 °C has been conducted to generate a ratio of 1.48 of Zn doped β-TCP. The products were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectrometer, and field emission scanning electron microscope (FESEM). Our results confirmed that the product was crystalline Zn2+-doped β-tricalcium phosphate. The incorporation of Zn+2 into the β-TCP lattice resulted in a shifting of diffraction peaks to higher 2θ values, which were attributed to the substitution of larger-sized Ca+2 ions with smaller-sized Zn2+ ions. A reduction in the intensity of the XRD peaks was also observed due to the reduction in the degree of crystallinity of the samples. Lattice parameters along the a and c-axis showed a gradual decrease in length with an increase in the amount of Zn2+ doping. This decrease was attributed to the replacement of Ca+2 ion by the smaller-sized Zn2+ ions. The microstructure of the powders consisted of microscale aggregates fused together. EDX analysis of all samples showed that the Zn2+ doping had successfully taken place and the amount of Zn2+ present in the samples was in good agreement with the theoretical values.

Large Size CH3NH3PbI3 Perovskite Microcrystalline with a Capsule-Free Cavity Box Structure Grown by Solvent Thermal Reaction

2021 ◽  
Vol 1032 ◽  
pp. 51-56
Author(s):  
Fei Han ◽  
Xi Ping Xi ◽  
Min Fan ◽  
Ling Ling Wang ◽  
Jin Ming Shi ◽  
...  
Keyword(s):  
Xrd Analysis ◽  
Thermal Reaction ◽  
Material Decomposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Large Size ◽  
Composition And Structure ◽  
Before And After ◽  
Box Structure ◽  
Technical Guidance

In the paper, a novel perovskite microcrystalline with a capsule-free cavity box structure was creatively prepared through solvent thermal reaction, and the composition and structure of CH3NH3PbI3 perovskite microcrystalline were further characterized by scanning electron microscope (SEM) and energy dispersive X-ray (EDX) element mapping. The SEM results show that the grain size of the prepared CH3NH3PbI3 perovskite microcrystalline is more than 100 μm. Furthermore, X-ray diffraction (XRD) analysis was used to characterize the material decomposition of perovskite microcrystals before and after 150 d of air aging. The XRD results indicate the prepared perovskite microcrystalline could be stably preserved in the air for 150 d without degradation. Our method provides technical guidance for further enriching the morphology of CH3NH3PbI3 perovskite microcrystalline.

Physicochemical Properties of Porous Starches from Different Botanical Origin

2010 ◽  
Vol 159 ◽  
pp. 363-370
Author(s):  
Hua Xi Xiao ◽  
Qin Lu Lin ◽  
Yue Wu ◽  
Wei Tian ◽  
Wei Wu
Keyword(s):  
Potato Starch ◽  
Enzyme Hydrolysis ◽  
Degree Of Crystallinity ◽  
Rice Starch ◽  
Adsorptive Capacity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Potato Starches ◽  
The Degree Of Crystallinity

Rice, maize and potato starches were hydrolyzed by amylase to obtain porous starches as final product. The adsorptive capacity, desorbed rates, degree of crystallinity and retrogradation properties of native and porous starches were investigated. The results showed that porous starches had the stronger adsorptive capacity and slower desorbed rate compared with native starches. In the three starch materials, the adsorptive capacity of rice starch for liquids was the strongest; the adsorptive capacity of potato starch for liquids was the weakest. the more flavors adsorbed, the more flavors desorbed. X-ray diffraction showed that Enzyme hydrolysis did not result in any significant changes in the degree of crystallinity of starch. The porous starches exhibited lower tendency of retrogradation as assessed by differential scanning calorimetry (DSC).

Mineralogical Analysis of Portland Cement Pastes Rehydrated

2020 ◽  
Vol 46 (1) ◽  
pp. 15-23
Author(s):  
Tiago Assunção Santos ◽  
Guilherme Augusto de Oliveira e Silva ◽  
Daniel Véras Ribeiro
Keyword(s):  
Portland Cement ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
X Ray ◽  
Curing Period ◽  
Hydraulic Binder ◽  
Before And After ◽  
Hydrated Products ◽  
Rehydration Process

Hydrated products, such as (hydrated) cement pastes, decomposition through physical-chemical alterations when submitted to high temperatures. One of the main factors that lead to microstructural changes during calcination up to 800ºC, is the dehydration phases of hydrated Portland cement. The present study sought to characterize crystalline phases occurring before and after calcination to the produced pastes using X-ray diffraction (XRD) analysis. Cement pastes were produced using Portland cement CP V-ARI RS, similar to type II (ASTM C150-07), with water/cement ratio 0.5. After a 28-day curing period, the pastes were calcinated at 800°C for 60 minutes with a 10°C/min heating rate. Afterwards, the newly produced hydraulic binder was cooled abruptly and reactivated through a rehydration process, and underwent analyses on the 7 and 28 day. During this study it was observed that the originally hydrated products can be rehydrated.

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