scholarly journals Synthesis and Characterization of Conductive Polypyrrole: The Influence of the Oxidants and Monomer on the Electrical, Thermal, and Morphological Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Abdirahman Yussuf ◽  
Mohammad Al-Saleh ◽  
Salah Al-Enezi ◽  
Gils Abraham
Keyword(s):  
Electrical Resistivity ◽  
Room Temperature ◽  
Oxidative Polymerization ◽  
Sodium Dodecyl ◽  
Conductive Polymer ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Structural Formation ◽  
Pyrrole Monomer

Conductive polymer, polypyrrole (PPy), was synthesized by chemical oxidative polymerization technique for a period of four hours at room temperature using pyrrole monomer (mPPy) in aqueous solution. Different oxidants such as ferric chloride (FeCl3) and ammonium persulphate (N2H8S2O8) and surfactant sodium dodecyl sulphate (C12H25NaO4S) were used. The produced PPy samples were characterized by using different techniques such as the electrical resistivity by four probe technique, thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The performance of the oxidants has been investigated and compared. It was found that both oxidants, FeCl3 and N2H8S2O8, have decreased electrical resistivity as a function of temperature, which means increased conductivity. However, FeCl3 has achieved better performance than N2H8S2O8, where it has achieved a lower resistivity of about 60 ohms at room temperature, which indicates higher conductivity of PPy samples with FeCl3 as an oxidant. Similarly, further investigation of FeCl3 oxidant has been conducted by varying its concentration, and its influence on the final properties was reported. It has been observed that the morphology of PPy samples has a significant influence on the conductivity. It was found that 0.1 M and 0.05 M concentrations of FeCl3 oxidant and monomer, respectively, have achieved better thermal stability, which is FeCl3/mPPy ratio of 2 as an optimum value. FTIR and XRD results confirmed the structural formation of polypyrrole from pyrrole monomer during the synthesizing process.

Synthesis and thermoelectric power factor of LSCO perovskites

2005 ◽  
Vol 886 ◽  
Author(s):  
Julio E. Rodriguez
Keyword(s):  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Power ◽  
Power Factor ◽  
Room Temperature ◽  
Morphological Properties ◽  
Measured Temperature ◽  
X Ray Diffraction ◽  
Thermoelectric Power Factor ◽  
X Ray

ABSTRACTMeasurements of Seebeck coefficient, S(T) and electrical resistivity, ρ(T) on polycrystalline La2−xSrxCuO4+d(LSCO) (0<x≤0.2) samples are reported. The Seebeck coefficient is positive in whole measured temperature range (77K and 300K) and it decreases with Sr content. At room temperature S(T) changes from 400 μ/K for the samples with the lowest levels of Sr to 30 μV/K for the samples with the highest Sr levels. The behavior of S(T) fits to Heikes model, which describes the behavior of Seebeck coefficient in systems where the correlated hopping is present. With the Sr content, the electrical resistivity changes its behavior from semiconducting to metallic and it took values from 2.4 to 10−3Ωcm. From S(T) and rho(T) measurements the thermoelectric power factor, PF was obtained. The maximum values for PF were about 5 μW/K2cm in the samples where x= 0.03, which are comparable to the typical values for conventional thermoelectric semiconductors. The structural and morphological properties of the samples were studied by x-ray diffraction analysis and Scanning Electron Microscopy (SEM) respectively. The behavior of transport properties opens de possibility of considering this family of perovskite-compounds as a thermoelectric material which works below room temperature.

scholarly journals Rheological, Thermal, Superficial, and Morphological Properties of Thermoplastic Achira Starch Modified with Lactic Acid and Oleic Acid

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4433 ◽  
Author(s):  
Carolina Caicedo ◽  
Rocío Yaneli Aguirre Loredo ◽  
Abril Fonseca García ◽  
Omar Hernán Ossa ◽  
Aldo Vázquez Arce ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Oleic Acid ◽  
Complex Viscosity ◽  
Thermoplastic Starch ◽  
Residual Energy ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rheological Analysis ◽  
Acid Agent

The modification of achira starch a thermoplastic biopolymer is shown. Glycerol and sorbitol, common plasticizers, were used in the molten state with organic acids such as oleic acid and lactic acid obtaining thermodynamically more stable products. The proportion of starch:plasticizer was 70:30, and the acid agent was added in portions from 3%, 6%, and 9% by weight. These mixtures were obtained in a torque rheometer for 10 min at 130 °C. The lactic acid managed to efficiently promote the gelatinization process by increasing the available polar sites towards the surface of the material; as a result, there were lower values in the contact angle, these results were corroborated with the analysis performed by differential scanning calorimetry and X-ray diffraction. The results derived from oscillatory rheological analysis had a viscous behavior in the thermoplastic starch samples and with the presence of acids; this behavior favors the transitions from viscous to elastic. The mixture of sorbitol or glycerol with lactic acid promoted lower values of the loss module, the storage module, and the complex viscosity, which means lower residual energy in the transition of the viscous state to the elastic state; this allows the compounds to be scaled to conventional polymer transformation processes.

Microstructure Evolution of a Fine Grain Al-50wt%Si Alloy Fabricated by High Energy Milling

2011 ◽  
Vol 479 ◽  
pp. 54-61 ◽  
Author(s):  
Fei Wang ◽  
Ya Ping Wang
Keyword(s):  
Grain Growth ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Method ◽  
X Ray ◽  
Fine Grain

Microstructure evolution of high energy milled Al-50wt%Si alloy during heat treatment at different temperature was studied. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that the size of the alloy powders decreased with increasing milling time. The observable coarsening of Si particles was not seen below 730°C in the high energy milled alloy, whereas, for the alloy prepared by mixed Al and Si powders, the grain growth occurred at 660°C. The activation energy for the grain growth of Si particles in the high energy milled alloy was determined as about 244 kJ/mol by the differential scanning calorimetry (DSC) data analysis. The size of Si particles in the hot pressed Al-50wt%Si alloy prepared by high energy milled powders was 5-30 m at 700°C, which was significantly reduced compared to that of the original Si powders. Thermal diffusivity of the hot pressed Al-50wt%Si alloy was 55 mm2/s at room temperature which was obtained by laser method.

Evolution of crystal structure of dual layered molecular conductor (ET)4ZnBr4(C6H4Cl2) with temperature

CrystEngComm ◽  
2021 ◽  
Author(s):  
Gennady V. Shilov ◽  
Elena I. Zhilyaeva ◽  
Sergey M. Aldoshin ◽  
Alexandra M Flakina ◽  
Rustem B. Lyubovskii ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Resistivity ◽  
Single Crystal ◽  
Room Temperature ◽  
Organic Conductor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Molecular Conductor ◽  
Abrupt Changes

Electrical resistivity measurements of a dual layered organic conductor (ET)4ZnBr4(1,2-C6H4Cl2) above room temperature show abrupt changes in resistivity at 320 K. Single-crystal X-ray diffraction studies in the 100-350 K range...

scholarly journals Effect of the Structural and Morphological Properties of Surfactant-Assisted Hydroxyapatite on Dermal Irritation and Antibacterial Activity

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6522
Author(s):  
Giovanni García Domínguez ◽  
Sebastián Diaz De La Torre ◽  
Lorena Chávez Güitrón ◽  
Erasto Vergara Hernández ◽  
Joan Reyes Miranda ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Micrococcus Luteus ◽  
Hexagonal Phase ◽  
Sodium Dodecyl ◽  
Clinical Signs ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Streptococcus Anginosus ◽  
Dermal Irritation ◽  
Cationic And Anionic Surfactants

Hydroxyapatite (HAp) nanoparticles with a homogeneous rod morphology were successfully synthesized using the hydrothermal method. The powders were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The antibacterial and dermal irritation analyses of the samples were performed and discussed. The use of cationic and anionic surfactants, namely, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), respectively, at a low concentration (2.5 mol%) modified the length/diameter (L/D) ratio of the HAp rods. Structural characterizations of hydroxyapatite synthesized without surfactant (HA), with 2.5 and 5 mol% of SDS (SDS− and SDS+, respectively), and with 2.5 and 5 mol% of CTAB (CTAB− and CTAB+, respectively) revealed well-crystallized samples in the hexagonal phase. The CTAB− sample presented antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Streptococcus anginosus, Staphylococcus aureus, Micrococcus luteus, and Klebsiella pneumoniae, suggesting that antimicrobial susceptibility was promoted by the bacterial nature and the use of the surfactant. Dermal irritation showed no clinical signs of disease in rabbits during the study, where there was neither erythema nor necrosis at the inoculation sites.

scholarly journals Viability of the microencapsulation of a casein hydrolysate in lipid microparticles of cupuacu butter and stearic acid

2013 ◽  
Vol 2 (1) ◽  
Author(s):  
Samantha Cristina Pinho ◽  
Janaina Costa Da Silva
Keyword(s):  
Stearic Acid ◽  
Room Temperature ◽  
Casein Hydrolysate ◽  
Polysorbate 80 ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Initial Amount ◽  
X Ray ◽  
Lipid Mixtures ◽  
Lipid Microparticles

Solid lipid microparticles produced with a mixture of cupuacu butter and stearic acid were used to microencapsulate a commercial casein hydrolysate (Hyprol 8052). The composition of the lipid matrix used for the production of the lipid microparticles was chosen according to data on the wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) of bulk lipid mixtures, which indicated that the presence of 10 % cupuacu butter was sufficient to significantly change the crystalline arrangement of pure stearic acid. Preliminary tests indicated that a minimum proportion of 4 % of surfactant (polysorbate 80) was necessary to produce empty spherical lipid particles with average diameters below 10 mm. The lipid microparticles were produced using 20 % cupuacu butter and 80 % stearic acid and then stabilized with 4 % of polysorbate 80, exhibiting an encapsulation efficiency of approximately 74 % of the casein hydrolysate. The melting temperature of the casein hydrolysate-loaded lipid microparticles was detected at 65.2 °C, demonstrating that the particles were solid at room temperature as expected and indicating that the incorporation of peptides had not affected their thermal behavior. After 25 days of storage, however, there was a release of approximately 30 % of the initial amount of encapsulated casein hydrolysate. This release was not thought to have been caused by the liberation of encapsulated casein hydrolysate. Instead, it was attributed to the possible desorption of the adsorbed peptides present on the surface of the lipid microparticles.

scholarly journals The effect of structural changes during sintering on the electric and magnetic traits of the Ni96.7Mo3.3 alloy nanostructured powder

2009 ◽  
Vol 41 (2) ◽  
pp. 175-184 ◽  
Author(s):  
L. Ribic-Zelenovic ◽  
M. Spasojevic ◽  
A. Maricic ◽  
M.M. Ristic
Keyword(s):  
Electrical Resistivity ◽  
Magnetic Permeability ◽  
Structural Relaxation ◽  
Crystalline Phase ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Fcc Lattice ◽  
Lower Permeability ◽  
Structural Powder

Ni96.7Mo3.3 powder was electrochemically obtained. An X-ray diffraction analysis determined that the powder consisted of a 20% amorphous and 80% crystalline phase. The crystalline phase consisted of a nanocrystalline solid nickel and molybdenum solution with a face-centred cubic (FCC) lattice with a high density of chaotically distributed dislocations and high microstrain value. The scanning electronic microscopy (SEM) showed that two particle structures were formed: larger cauliflower-like particles and smaller dendriteshaped ones. The thermal stability of the alloy was examined by differential scanning calorimetry (DSC) and by measuring the temperature dependence of the electrical resistivity and magnetic permeability. Structural powder relaxation was carried out in the temperature range of 450 K to 560 K causing considerable changes in the electrical resistivity and magnetic permeability. Upon structural relaxation, the magnetic permeability of the cooled alloy was about 80% higher than the magnetic permeability of the fresh powder. The crystallisation of the amorphous portion of the powder and crystalline grain increase occurred in the 630 K to 900 K temperature interval. Upon crystallisation of the amorphous phase and crystalline grain increase, the powder had about 50% lower magnetic permeability than the fresh powder and 3.6 times lower permeability than the powder where only structural relaxation took place.

Influence of Gd Addition on the Structure and Capability of Ni-Mn-In Metamagnetic Shape Memory Alloys

2012 ◽  
Vol 535-537 ◽  
pp. 950-953
Author(s):  
Li Na Bai ◽  
Gui Xing Zheng ◽  
Zhi Jian Duan ◽  
Jian Jun Zhang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Transition Temperature ◽  
Martensitic Transformation ◽  
Room Temperature ◽  
Vibrating Sample Magnetometry ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The influences of Gd concentration on martensitic transformation and magnetic properties of NiMnIn alloys were investigated by differential scanning calorimetry (DSC) , vibrating sample magnetometry (VSM), X-ray diffraction (XRD) and etc. It is Observed through the experiment: the addition of Gd enhances martensite transition temperature;X-ray diffraction analysis of experimental alloys is revealed that to the mixture is martensite and austenite at room temperature; content of Gd is not proportional to the improvement of magnetic property.

Study of thermal properties of Ga0.5In1.5Se3 by differential scanning calorimetry

2021 ◽  
pp. 2150407
Author(s):  
S. I. Ibrahimova
Keyword(s):  
Crystal Structure ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Thermal Effects ◽  
Room Temperature ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Hexagonal Symmetry ◽  
Scanning Calorimetry ◽  
X Ray

The crystal structure and thermal properties of the [Formula: see text] compound have been investigated. Structural studies were performed by X-ray diffraction at room temperature. The crystal structure of this compound was found to correspond to the hexagonal symmetry of the space group P61. Thermal properties were studied using a differential scanning calorimetry (DSC). It was found in the temperature range [Formula: see text] that thermal effects occur at temperatures [Formula: see text] and [Formula: see text]. The thermodynamic parameters of these effects are calculated.

The structures and phase transitions in 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2]

2019 ◽  
Vol 75 (6) ◽  
pp. 1144-1151
Author(s):  
Tamara J. Bednarchuk ◽  
Wolfgang Hornfeck ◽  
Vasyl Kinzhybalo ◽  
Zhengyang Zhou ◽  
Michal Dušek ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Single Crystal ◽  
Room Temperature ◽  
Variable Temperature ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Hybrid Compound ◽  
Space Group ◽  
X Ray

The organic–inorganic hybrid compound 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2] (4apFeS), was obtained by slow evaporation of the solvent at room temperature and characterized by single-crystal X-ray diffraction in the temperature range from 290 to 80 K. Differential scanning calorimetry revealed that the title compound undergoes a sequence of three reversible phase transitions, which has been verified by variable-temperature X-ray diffraction analysis during cooling–heating cycles over the temperature ranges 290–100–290 K. In the room-temperature phase (I), space group C2/c, oxygen atoms from the closest Fe-atom environment (octahedral) were disordered over two equivalent positions around a twofold axis. Two intermediate phases (II), (III) were solved and refined as incommensurately modulated structures, employing the superspace formalism applied to single-crystal X-ray diffraction data. Both structures can be described in the (3+1)-dimensional monoclinic X2/c(α,0,γ)0s superspace group (where X is ½, ½, 0, ½) with modulation wavevectors q = (0.2943, 0, 0.5640) and q = (0.3366, 0, 0.5544) for phases (II) and (III), respectively. The completely ordered low-temperature phase (IV) was refined with the twinning model in the triclinic P{\overline 1} space group, revealing the existence of two domains. The dynamics of the disordered anionic substructure in the 4apFeS crystal seems to play an essential role in the phase transition mechanisms. The discrete organic moieties were found to be fully ordered even at room temperature.

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