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1.
Vicat softening point temperature (T
V) and heat deflection temperature (T
d) are important parameters for characterization of heat resistant properties of polymeric materials. PP/Al(OH)3/Mg(OH)2 flame retardant composites were prepared using a twin-screw extruder, and the T
V and T
d of the composites were measured. The results showed that the T
V and T
d increased nonlinearly with an addition of the weight percentage of the flame retardant additives except for individual data
points, while the T
V and T
d decreased with increasing the filler particle size when the content of flame retardant additives was constant. Under the
same conditions, filling small amount of zinc borate into the composites might improve the heat resistant properties of the
composite systems. Moreover, the morphology of the impact fracture surface of the specimens was observed by means of scanning
electron microscope to understand the dispersion and distribution of the filler particles in the PP matrix. 相似文献
2.
A simple and mild wet-chemical approach was developed for the synthesis of one-dimensional (1D) In(OH)3 nanostructures. By calcining the 1D In(OH)3 nanocrystals in air at 250 °C, 1D In2O3 nanocrystals with the same morphology were obtained. TEM results show that both 1D In(OH)3 and 1D In2O3 are composed of uniform nanotube bundles. SAED and XRD patterns indicate that 1D In(OH)3 and 1D In2O3 nanostructures are single crystalline and possess the same bcc crystalline structure as the bulk In(OH)3 and In2O3, respectively. TGA/DTA analyses of the precursor In(OH)3 and the final product In2O3 confirm the existence of CTAB molecules, and its content is about 6%. The optical absorption band edge of 1D In2O3 exhibits an evident blueshift with respect to that of the commercial In2O3 powders, which is caused by the increasing energy gap resulted from decreasing the grain size. A relatively strong and broad
purple-blue emission band centered at 440 nm was observed in the room temperature PL spectrum of 1D In2O3 nanotube bundles, which was mainly attributed to the existence of the oxygen vacancies. 相似文献
3.
Hamideh Saravani Milad Takhsha Ghahfarokhi Masoud Rafigh Esmaeilzaei 《Journal of Inorganic and Organometallic Polymers and Materials》2016,26(3):660-666
In this paper, for the first time, synthesis of [Ba(H2O)8][Ni(dipic)2] complex and preparation of NiBaO2 nano-oxide are reported through thermal decomposition under surfactant free condition. This novel complex was characterized by Fourier transform infrared spectroscopy (FT-IR), ultra violet–visible spectroscopy, conductivity measurement and elemental analysis. Formation of novel nanoparticles was supported by FT-IR and energy-dispersive X-ray spectroscopy and the orthorhombic structure of nanocrystals was confirmed by powder X-ray diffraction analysis. In addition, size distribution as well as uniform morphology of prepared nano-oxide were recorded by dynamic light scattering analysis and field-emission scanning electron microscopy, respectively. Magnetic features measured by vibrating sample magnetometer, illustrate superparamagnetic behavior of the oxide. 相似文献
4.
Hydrosilicate nanotubes of the variable composition (Mg,Fe,Co,Ni)3Si2O5(OH)4 with a chrysotile structure have been synthesized under hydrothermal conditions at temperatures of 250–450°C and pressures
of 30–100 MPa in media of different compositions. The conditions and ranges of formation of nanotubular hydrosilicates of
the compositions under investigation have been determined. It has been demonstrated that the type of cation of the octahedral
layer in the chrysotile structure has a decisive effect on the physicochemical conditions, mechanism, and rate of formation
of nanotubes, as well as on their structure, morphology, and sizes. 相似文献
5.
XiaoMeng Chen GuangTao Fei Jian Yan YanQing Zhu Li De Zhang 《Nanoscale research letters》2010,5(9):1387-1392
In this paper, ZnGa2O4 hierarchical nanostructures with comb-like morphology are fabricated by a simple two-step chemical vapor deposition (CVD)
method: first, the Ga2O3 nanowires were synthesized and employed as templates for the growth of ZnGa2O4 nanocombs; then, the as-prepared Ga2O3 nanowires were reacted with ZnO vapor to form ZnGa2O4 nanocombs. Before the reaction, the Au nanoparticles were deposited on the surfaces of Ga2O3 nanowires and used as catalysts to control the teeth growth of ZnGa2O4 nanocombs. The as-prepared ZnGa2O4 nanocombs were highly crystallized with cubic spinel structure. From the photoluminescence (PL) spectrum, a broad band emission
in the visible light region was observed of as-prepared ZnGa2O4 nanocombs, which make it promising application as an optical material. 相似文献
6.
Nanostructure control of β-Ni(OH)2 was attempted by adopting hydrothermal treatment for the high specific surface area (high-SSA) β-Ni(OH)2 in the presence of guanidine carbonate. β-Ni(OH)2 nanosheets-linked structures could be synthesized from high-SSA β-Ni(OH)2 owing to the strong effects of guanidine carbonate for keeping or enlarging SSA during hydrothermal treatment. The discharging
capacities of the high-SSA sample showed the highest capacity above 80 % at 0.2C. However, the capacities were decreased with decreasing SSA of the β-Ni(OH)2 prepared. It was also found that, at lower SSA, charging/discharging rates below 1C did not affect the discharging capacity, i.e., the almost same capacities for 0.2C and 1C. Cyclic voltammetry revealed that the electrochemical reactions for the charging/discharging were considered to be reversible
and smooth at various scanning rates. The rate-determining step of the electrochemical reaction is considered to be regulated
by the diffusion of the active species involved for the lower SSA samples. However, for the higher SSA sample (280 m2 g−1) obtained at 200 °C in the presence of 1.0 × 10−1 mol L−1 guanidine carbonate strongly indicates the effects of the rate of surface reaction or electronic conductivity on rate-determining
step of charging/discharging of the material. 相似文献
7.
The thermal behavior of natural borosilicate howlite, Ca2B5SiO9(OH)5, is studied by the methods of high-temperature X-ray diffraction and differential thermal analysis in the temperature range of 30–1100°C. The thermal expansion is anisotropic (αmax/αmin = 3.6); the degree of anisotropy increases (αmax/αmin = 4.3) with a temperature increase up to 480°C (360–480°C). 相似文献
8.
The results of studying the thermal behavior of natural boron albite–reedmergnerite NaBSi3O8 and aqueous boricilicate–searlesite NaBSi2O5(OH)2 obtained by the method of hydrothermal synthesis are presented. In the investigated temperature range, reedmergnerite (30–780°C) does not undergo phase transformations. Thermal expansion is sharply anisotropic, which is a characteristic feature of the expansion of feldspars. Aqueous borosilicate searlesite (25–750°C) is amorphized above 400°C as a result of dehydration and cristobalite crystallizes from the amorphous phase. The expansion of searlesite is relatively isotropic. 相似文献
9.
R. N. Rumyantsev A. A. Il’in K. O. Denisova A. P. Il’in A. V. Volkova 《Glass and Ceramics》2017,73(9-10):374-377
10.
Syed S. Amin Shu-you Li Xiaoxia Wu Weiqiang Ding Terry T. Xu 《Nanoscale research letters》2010,5(2):338-343
High-yield synthesis of TiO2 one-dimensional (1D) nanostructures was realized by a simple annealing of Ni-coated Ti grids in an argon atmosphere at 950 °C
and 760 torr. The as-synthesized 1D nanostructures were single crystalline rutile TiO2 with the preferred growth direction close to [210]. The growth of these nanostructures was enhanced by using catalytic materials,
higher reaction temperature, and longer reaction time. Nanoscale tensile testing performed on individual 1D nanostructures
showed that the nanostructures appeared to fracture in a brittle manner. The measured Young’s modulus and fracture strength
are ~56.3 and 1.4 GPa, respectively. 相似文献
11.
Mg(OH)2 films on Al substrates were fabricated by ink-jet printing, and they were applied as photocatalysts in solar fuels production (H2 and CH3OH) from CO2 and H2O conversion. The films were fabricated by means of a deposition of a solution composed of magnesium complex nanoparticles over aluminum foils, which were submitted to a heat treatment to promote the crystallization of Mg(OH)2. The films were characterized by razing incidence X-ray diffraction (GZXD), Fourier-transform infrared spectroscopy (FTIR), Scanning electronic microscopy, X-ray photoelectron spectroscopy (XPS), and N2 physisorption by BET method. The Mg(OH)2 was detected in all the samples synthesized with 1 to 40 layers. According to XPS and FTIR analysis, it was detected the presence of carbonates related to Mg3O(CO3)2 and Al0 and Al3+ due to the substrate. The highest photocatalytic activity was reached using 30 layers of Mg(OH)2 for H2 and CH3OH generation, which it was 268 and 15 µmol g??1h??1, respectively. These results were associated to the presence of adequate amounts of MgO and Al2O3 that promote an efficient transfer of the photogenerated electrons between them. Furthermore, the formation of porous structures with high surface area and relative high roughness promoted an increase in the mass transport between the gas and liquid phase, which increase the effectiveness of the photocatalysts. 相似文献
12.
Zai-xing Yang Wei Zhong Yan-xue Yin Xin Du Yu Deng Chaktong Au You-wei Du 《Nanoscale research letters》2010,5(6):961-965
Single-crystalline Cd(OH)2 or CdO nanowires can be selectively synthesized at 150 °C by a simple hydrothermal method using aqueous Cd(NO3)2 as precursor. The method is biosafe, and compared to the conventional oil-water surfactant approach, more environmental-benign.
As revealed by the XRD results, CdO or Cd(OH)2 nanowires can be generated in high purity by varying the time of synthesis. The results of FESEM and HRTEM analysis show
that the CdO nanowires are formed in bundles. Over the CdO-nanowire bundles, photoluminescence at ~517 nm attributable to
near band-edge emission of CdO was recorded. Based on the experimental results, a possible growth mechanism of the products
is proposed. 相似文献
13.
The magnetite nanoparticles and nanocomposite “Nanotube of hydrosilicate Mg—magnetite nanoparticles—Mg-ChR-NT/Fe3O4-NP” were obtained by coprecipitation. The composition of the synthesized samples has been established by X-ray diffraction. Using transmission electron microscopy, the presence of magnetite nanoparticles has been detected both inside the NTs and at the external surface of the NT walls. The specific surface of the NTs, nanoparticles, and composite is determined. 相似文献
14.
The following investigation reports the synthesis of novel complex [Fe(opd)3]2[Ba(CN)8] and preparation of BaFe2O4 nanoparticles through thermal decomposition without using any surfactant. The complex was characterized via Furrier transform infrared spectroscopy (FT-IR), ultra violet-visible spectroscopy (UV–vis), conductivity measurement and elemental analysis. The synthesized crystals of inorganic precursor complex was transferred to furnace, where they were calcined under normal atmosphere condition at 900 °C for 4 h. Formation of BaFe2O4 was supported by FT-IR and energy-dispersive X-ray analysis. Hexagonal structure of nano-oxide was confirmed on powder X-ray diffraction. Furthermore, uniform morphology of nanocrystals were reported by scanning electron microscopy. The saturation magnetization (22 emu/g), remanent magnetization (6 emu/g) and coercivity (400 Oe) reported on vibrating sample magnetometer curve illustrates the promising industrial and medicinal applications of prepared mixed oxide. 相似文献
15.
Yang Yu Zhoufeng Bian Fujiao Song Juan Wang Qin Zhong Sibudjing Kawi 《Topics in Catalysis》2018,61(15-17):1514-1527
Herein, we studied the influence of calcination temperature (500–800 °C) of Ni/CeO2 and Ni/Ce0.8Zr0.2O2 catalysts on the specific surface area, pore volume, crystalline size, lattice parameter, chemical bonding and oxidation states, nickel dispersion and CH4/CO production rate in CO2 methanation. In general, the catalytic performance revealed that Zr doping catalysts could increase the CH4 production rate. Combined with the production rate and the characterizations results, we found that the combination of nickel dispersion, peak area of CO2–TPD and OII/(OII + OI)) play the critical role in increasing the CH4 production rate. It is well to be mentioned that the CO production rate is strongly influenced by the nickel dispersion. Furthermore, the in-situ DRIFTS confirmed that the CO originates from the decomposition of H-assisted formate species. 相似文献
16.
V. P. Danilov E. A. Frolova D. F. Kondakov L. I. Avdyushkina V. T. Orlova 《Theoretical Foundations of Chemical Engineering》2011,45(5):697-701
The polytherms of ice melting in sections of the Ca(NO3)2-Mg(NO3)2-CO(NH2)2-H2O system with different component ratios were studied in the temperature interval from 0 to −40°C. A series of nitrate and
nitrate-carbonate reagents that are promising for the creation of anti-acing reagents were found, which form eutectics with
ice at temperatures from −25 to −39°C. Their properties, viz., melting properties with respect to ice and corrosiveness on
metals and alloys, were determined. An effective corrosion inhibitor was selected. 相似文献
17.
In this paper, solvothermal synthesis of submicron nanocrystalline Y2O3: Eu particles with and without surface modifier (β-alanine and Tween-80) is investigated. X-ray diffraction ananlysis confirms
the one-step formation of Y2(OH)5NO3H2O phase during solvothermal process and its conversion to Y2O3: Eu after heat treatment at 600 °C. Fourier transformation infrared spectroscopy showed that C=C, C–C and C–H peaks are corresponded
to the surface modifiers i.e. tween-80 and β-alanine. Scanning electron microscopy and transmission electron microscopy images
also showed that the modifier results in the particle morphology improvement from sheet-like to submicron spherical particles.
Photoluminescence experiments indicated that the emission intensity increases due to the morphology modification. 相似文献
18.
T. P. Maslennikova E. N. Korytkova O. M. Kuznetsova L. N. Pivovarova 《Glass Physics and Chemistry》2016,42(3):288-294
The interaction of an aqueous solution of silver nitrate with Mg3Si2O5(OH)4 hydrosilicate nanotubes under atmospheric conditions at 50 and 80°C and under dynamic conditions with subsequent annealing at 300°C has been investigated. The intercalation of AgNO3 solutions into the internal channel and interlayer spaces of the nanotube structure and the crystallization of the silver particles of the spherical shapes on the nanotube surface have been established. 相似文献
19.
Zhong-Wen Liu Hyun-Seog Roh Ki-Won Jun Sang-Eon Park Taek-Yong Song 《Korean Journal of Chemical Engineering》2002,19(5):742-748
The catalytic behavior of Ni/Ce-ZrO2/θ-Al2O3 has been investigated in the partial oxidation of methane (POM) toward synthesis gas. The catalyst showed high activity and
selectivity due to the heat treatment of the support and the promotional effect of Ce-ZrO2. It is suggested that the support was stabilized through the heat treatment of γ-Al2O3 and the precoating of Ce-ZrO2, on which a protective layer was formed. Moreover, sintering of the catalyst was greatly suppressed for 24 h test. Pulse
experiments of CH4, O2 and/or CH4/O2 with a molar ratio of 2 were systematically performed over fresh, partially reduced and well reduced catalyst. Results indicate
that CH4 can be partially oxidized to CO and H2 by the reactive oxygen in complex NiOx species existing over the fresh catalyst. It is demonstrated that POM over Ni/Ce-ZrO2/θ-Al2O3 follows the pyrolysis mechanism, and both the carbonaceous materials from CH4 decomposition over metallic nickel and the reactive oxygen species present on NiOx and Ce-ZrO2 are intermediates for POM. 相似文献
20.
A new compound of (Rb,K)2Cu3(P2O7)2 is obtained by high-temperature reactions from a mixture of RbNO3, KNO3, Cu(NO3)2, and (NH4)4P2O7. The crystal structure was solved by direct methods and refined to R 1 = 0.056 for 5022 independent reflections. The compound belongs to a rhombic crystal system, P212121, Z = 8, a = 9.9410(7) Å, b = 13.4754(6) Å, c = 18.6353 (3) Å, and R = 0.056. The basis of the structure is a complex copper-phosphate skeleton of the composition of [Cu3(P2O7)2]2–, which can be regarded as consisting of two types of heteropolyhedral layers parallel to the (001) plane. The layers are alternated with each other, forming a frame, in the cavities of which the positions of alkali cations are located, statistically populated with K+ and Rb+ ions. Based on the refined populations of the positions of alkali cations, an exact chemical formula of the compound can be written as Rb1.28K0.72Cu3(P2O7)2. The compound is the most complex among those known to this day of the composition of A2 IB3 II(P2O7)2 (A = Li, Na, K, Rb, or Cs; B = Ni, Cu, or Zn). 相似文献