Polymer Composite
Daily Maria Gallegos; Denis Mayta; Gerhard Paúl Rodriguez; Fredy Alberto Huaman; Fernando Alonso Cuzziramos
Abstract
The effect of the addition of alpaca fibers on the mechanical response of geopolymeric mortars was studied using uniaxial compression tests. The studied mortars were manufactured by mixing mining tailings, fine sand and variable percentages of alpaca wool fibers. The mechanical results show a higher ...
Read More
The effect of the addition of alpaca fibers on the mechanical response of geopolymeric mortars was studied using uniaxial compression tests. The studied mortars were manufactured by mixing mining tailings, fine sand and variable percentages of alpaca wool fibers. The mechanical results show a higher degree of deformation, up to 6%, for the mortar mixtures with higher amounts of wool fiber in their composition, that is, the decrease in maximum compressive strength was demonstrated as the volume increased of added fibers, the values were from 32 to 9 MPa for samples with 0 and 8 % Vol. of added fibers, respectively. On the other hand, studies of the real density and the average porosity were carried out, obtaining values of 2.59 g/cm3 and 31 %, respectively. Additionally, the morphological analysis was carried out using microscopy in which a continuous binder geopolymer phase could be seen and within this phase a phase of sand and fibers.
Anamika Srivastava; Anjali Yadav; Manish Srivastava
Abstract
The catalytic activity of the Au NPs and Au 3+ metal ions used in the oxidation of carbonyl compounds by in situ generated Na2FeO4 from an industrial point of view. In the subsequent study used the chemical reduction and green method in favor of the fabrication of 30 to70nm in the size of Au NPs. Carbonyl ...
Read More
The catalytic activity of the Au NPs and Au 3+ metal ions used in the oxidation of carbonyl compounds by in situ generated Na2FeO4 from an industrial point of view. In the subsequent study used the chemical reduction and green method in favor of the fabrication of 30 to70nm in the size of Au NPs. Carbonyl compounds converted to aromatic and aliphatic acids by the oxidation process. Au NPs give better yield as compared to Au 3+ ion since in case of bulk metal the size is enlarged and surface area reduce but converted to nanoparticles the surface area increased so catalytic activity augmented.
Stefan Andersson; Paul Inge Dahl; Stephen A. Shevlin; Ingeborg-Helene Svenum; Yngve Larring; Julian R. Tolchard; Zheng Xiao Guo
Abstract
Experimental and complementary modelling studies on the potential use of iron oxide nanoparticles in chemical looping reforming processes have been performed. In order to avoid coarsening of the nanoparticles, and thereby loss of reactivity, at relevant process temperatures (700-900°C), the active ...
Read More
Experimental and complementary modelling studies on the potential use of iron oxide nanoparticles in chemical looping reforming processes have been performed. In order to avoid coarsening of the nanoparticles, and thereby loss of reactivity, at relevant process temperatures (700-900°C), the active metal oxide was embedded in an inert support material of lanthanum silicate. Micro reactor tests indicate that partial combustion occurs in reactions of reduced iron oxide with methane instead of pure reforming. Density Functional Theory and kinetic Monte Carlo calculations have been used to support and complement the experiments. The modelling supports efficient reactivity towards exposure of hydrogen, which is also observed experimentally. Reactivity towards methane is only tested for the fully oxidized state, Fe2O3, and not for the reduced oxide, giving results that are complementary to the experiments. Copyright © 2018 VBRI Press.
Nadejda N. Begletsova; Oksana A. Shinkarenko; Ekaterina I. Selifonova; Olga Yu. Tsvetkova; Andrey M. Zakharevich; Rimma K. Chernova; Aleksey A. Kletsov; Evgeny G. Glukhovskoy
Abstract
In this paper a methodology of chemical synthesis of copper nanoparticles stabilized with surfactant cetylpyridinium chloride (CPC) micelles has been developed. By varying of the volume of a reduction agent hydrazine hydrate (HH) and value of pH of the reactionary environment the optimum conditions for ...
Read More
In this paper a methodology of chemical synthesis of copper nanoparticles stabilized with surfactant cetylpyridinium chloride (CPC) micelles has been developed. By varying of the volume of a reduction agent hydrazine hydrate (HH) and value of pH of the reactionary environment the optimum conditions for synthesis of copper nanoparticles with a stable size ranging from 40 to 80 nm were found. The copper nanoparticles obtained by this methodology have a widely perspective for use in such fields as medicine, chemistry, electronics (Langmuir-Blodgett films with conductive properties). The synthesized copper nanoparticles were characterized by scanning electron microscopy (SEM) and UV-visible spectroscopy.
Mykola Kartel; Yuriy Sementsov; Galyna Dovbeshko; Liudmyla Karachevtseva; Stanislav Makhno; Tatiana Aleksyeyeva; Yulia Grebel
Abstract
An effective cheap method for graphene nanoparticles (GNP) production with controlled size distribution was developed based on anodic oxidation of condensed exfoliated graphite. As it is shown, under certain condition the GNP could be self-organized into a 3-dimensional structure that could be important ...
Read More
An effective cheap method for graphene nanoparticles (GNP) production with controlled size distribution was developed based on anodic oxidation of condensed exfoliated graphite. As it is shown, under certain condition the GNP could be self-organized into a 3-dimensional structure that could be important for understanding of the GNP interaction with different type of surfaces. Based on this feature, a synthesis method for preparation of composites containing GNP and polychlorotrifluoroethylene (PCTFE) was developed. Raman spectroscopy of GNP and GNP/PCTFE revealed a good crystalline structure of synthesized nanoparticles. Laser correlation spectroscopy and electron microscopy studies show that average size of particles ranges from tens to thousands nanometers and thickness consists ten or more graphene layers. We found that conductivity of GNP is of electronic nature. The real and imaginary parts of complex permittivity in the microwave range and electric conductivity at low frequencies were found to be a nonlinear function of a volume content of GNP in GNP/PCTFE composite. It could be explained by a presence of the percolation threshold equals to 0.5 wt.%. Low percolation threshold of GNP/PCTFE composite as self-organized 3D structure, could be a certificate of high surface energy for the particles strongly interacting with the surrounding media.
Henam Premananda Singh; Sarbjeet Singh Gujral; Surinder Kumar Sharma; Rakesh Kumar Sharma
Abstract
In this work we have successfully prepared spherical and chain type silver nanoparticles of excellent size’s homogeneity, reproducibility and stability using tannic acid. The synthesized nanometallic structures were characterized for their shape, size, thermal stability and crystalline nature. ...
Read More
In this work we have successfully prepared spherical and chain type silver nanoparticles of excellent size’s homogeneity, reproducibility and stability using tannic acid. The synthesized nanometallic structures were characterized for their shape, size, thermal stability and crystalline nature. The mechanism for the formation of Ag NPs and shape evolution of the chain structure has been vividly explained. Further, these NPs were found to exhibit significant antibacterial activity against gram negative Escherichia coli bacteria but to different extend indicating the influence of particles morphology on their antibacterial behaviours.
Abhishek Kumar Arya; Bhanu Pratap Singh; Jeevan Jyoti; Santwana Pati; S.R. Dhakate
Abstract
Vertically aligned carbon nanotube (VACNT) arrays are widely studied because of their immense potential in a wide range of applications. In order to tailor the properties of carbon nanotubes (CNTs) for a particular application, vertical alignment in the form of sheet is a major breakthrough. Herein ...
Read More
Vertically aligned carbon nanotube (VACNT) arrays are widely studied because of their immense potential in a wide range of applications. In order to tailor the properties of carbon nanotubes (CNTs) for a particular application, vertical alignment in the form of sheet is a major breakthrough. Herein we report an economic and effective strategy developed to synthesise aligned multiwalled carbon nanotube sheets using Al powder as buffer layer. We achieved easy growth of VACNTs sheets using toluene/ferrocene solution in a two-zone furnace by chemical vapor deposition method. First zone was set at temperature 200 ° C and other zone was set at temperature 750 ° C for the synthesis of VACNTs. Almost 500 µm long VACNT sheet was grown. We observed the significant growth of VACNT sheet on Al powdered quartz substrate in nitrogen medium. Uniform length of CNTs was maintained all over the sheet and additionally nitrogen is an economical alternative rather than other inert gases.
H. K. Dahule; S. J. Dhoble
Abstract
We have synthesized series of new phosphorescent cyclometalated iridium (III) complexes Ir(Br-DPQ)2(acac), with 2-(4-bromo-phenyl)-4-phenyl-quinoline (Br-DPQ) ligand and Ir(Cl-BrDPQ)2 (acac) with 4-chloro-2-(4-bromophenyl)-4-phenyl quinoline (Cl-BrDPQ) ligand. Synthesized complexes and ligands were characterized ...
Read More
We have synthesized series of new phosphorescent cyclometalated iridium (III) complexes Ir(Br-DPQ)2(acac), with 2-(4-bromo-phenyl)-4-phenyl-quinoline (Br-DPQ) ligand and Ir(Cl-BrDPQ)2 (acac) with 4-chloro-2-(4-bromophenyl)-4-phenyl quinoline (Cl-BrDPQ) ligand. Synthesized complexes and ligands were characterized by X-ray diffraction, elemental analysis, infrared spectroscopy (FTIR) and thermal analysis (TGA/DTA,DSC). UV-vis absorption and emission spectroscopy, photoluminescence (PL) emission peaks of Br-DPQ and Cl-BrDPQ in different solvents such as chloroform, dichloromethane, THF, acetic acid and formic acid is between 425 to 460 nm The metal complex display pure red luminescence in solution and in powder states in the range of λmax 615-651 nm. The iridium metal complex Ir(Br-DPQ)2(acac) where (Br-DPQ=2-(4-bromo phenyl)-4-phenyl quinoline shows strong 1MLCTand 3MLCT absorption peak at, 227, 265, 283, 346, and 432 nm in tetrahydrofuran (THF) solution and Ir(Cl-BrDPQ)2(acac) where (Cl-BrDPQ)=4chloro2-(4-Bromo phenyl)-4-phenyl quinoline shows strong 1MLCTand 3MLCT absorption peak at 262, 330, 438, 476, 505 and 535 nm in dichloromethane solution. It is suggested that the synthesized iridium complexes may be efficiently used as the emissive dopants in phosphorescent organic light-lmitting devices (PhOLEDs). Thus these complexes could be promising candidates for potential applications in Phosphorescent organic light-emitting diodes PhOLEDs, light-emitting electrochemical cells and solid-state organic lighting applications.
Kai Yan; Jiayou Liao; Xu Wu; Xianmei Xie
Abstract
A series of eco-friendly Cu-hydrotalcite (HT) catalysts (Cu-Fe, Cu-Al, Cu-Cr) were facilely and successfully synthesized by a modified co-precipitation method. The as-prepared Cu-hydrotalcite catalysts were highly selective for the synthesis of Anchorvalue-added furfural diethyl acetal and Anchorbenzoin ...
Read More
A series of eco-friendly Cu-hydrotalcite (HT) catalysts (Cu-Fe, Cu-Al, Cu-Cr) were facilely and successfully synthesized by a modified co-precipitation method. The as-prepared Cu-hydrotalcite catalysts were highly selective for the synthesis of Anchorvalue-added furfural diethyl acetal and Anchorbenzoin ethyl ether, whereas furfural diethyl acetal (97.5% selectivity at 49.3% conversion of furfural) and benzoin ethyl ether (98.4% selectivity at 43.7% conversion of benzaldehyde) were highly selectively produced on the Cu-Fe hydrotalcite catalyst, respectively. AnchorThe eco-friendly Cu-hydrotalcite catalysts were easy to be recycled and maintained high stability, which may be a good candidate for the general application in the reaction of aldehyde and ethanol.
V.K Mourya; Nazma N. Inamdara;Ashutosh Tiwari
Abstract
Deacetylation of chitin affords chitosan, a polymer, widely studied for its pharmaceutical and nonpharmaceutical applications. The hurdle in comprehending these applications is its limited solubility. Carboxymethylation of chitosan helps to surmount this hurdle with its improved solubility in water. ...
Read More
Deacetylation of chitin affords chitosan, a polymer, widely studied for its pharmaceutical and nonpharmaceutical applications. The hurdle in comprehending these applications is its limited solubility. Carboxymethylation of chitosan helps to surmount this hurdle with its improved solubility in water. Though there is ample of research related to carboxymethyl chitosan (CMC) the focused review of the topic is unavailable. Hence an attempt is made in this review to cover the recent findings pertaining to synthesis, characterization of CMC and its applications especially in pharmaceutical field. CMC has been synthesized by ways as direct alkylation, reductive alkylation, Michael addition and characterized by FTIR, NMR spectroscopy, and DSC, titrimetry, viscometry, gel permeation chromatography, X-ray diffraction and capillary zone electrophoresis. The carboxymethyl group can be present at O or N or both the atoms of chitosan molecule. The CMC possess modulated physical and biological properties as chelating, sorption, moisture retention, cell functioning antioxidant, antibacterial, antiapoptotic etc. CMC is used in sustained or controlled release drug delivery, pH responsive drug delivery, DNA delivery as permeation enhancer etc. CMC can be further modified with alkylation, acylation, and grafting. Carboxyalkylation of chitosan yield carboxyethyl, carboxybutyl chitosans. These analogues of CMC may be helpful in substantiating the applications of chitosan.