CR/SBS/CEVA-g-MMA/n-BMA胶粘剂的研制

以ＣＲ、苯乙烯丁二烯苯乙烯嵌段共聚物（ＳＢＳ）和氯化乙烯乙酸乙烯酯共聚物（ＣＥＶＡ）３种固体物料为接枝母体,以甲基丙烯酸甲酯（ＭＭＡ）和甲基丙烯酸正丁酯（ｎＢＭＡ）为接枝单体,在溶剂回流温度下,空气氛围中,以过氧化二苯甲酰（ＢＰＯ）为引发剂进行接枝共聚,制得了共混接枝共聚胶粘剂。此种胶粘剂的单体转化率、接枝率、初粘强度都有较大的提高,其广谱性能也有所改善。     

Structure and superconducting properties of layered perovskite-like compounds Y1 ? 2xCaxPrxBa2Cu3Oy and Y1 ? xBa2PrxCu3 ? xZnxOy

The conditions of preparation of Y_{1 − x} Pr _x Ba₂Cu_{3 − x} Zn _x O _y and Y_{1 − 2x} Ca _x Pr _x Ba₂Cu₃O _y solid solutions with an Y-123-type structure in the orthorhombic crystal system by the method of solid-phase chemical reactions have been determined. The concentration dependences of the unit cell parameters for these solid solutions have been established. The temperature dependences of the resistivity of the synthesized compounds have been investigated, the critical temperatures of the superconducting transition have been determined, and their variation as a function of the type and content of the introduced dopants has been analyzed. It has been demonstrated that, in the Y_{1 − x} Pr _x Ba₂Cu_{3 − x} Zn _x O _y samples, individual dopants have a combined effect on the suppression of the superconducting properties, whereas in the Y_{1 − 2x} Ca _x Pr _x Ba₂Cu₃O _y samples, calcium and praseodymium ions interact with each other when they are simultaneously introduced into the yttrium sublattice.     

PP/POE/PE/CaCO3/PP-g-MAH复合材料力学性能的研究

采用熔融共混法制备聚丙烯/聚烯烃弹性体/聚乙烯/马来酸酐接枝聚丙烯（PP/POE/PE/CaCO3/PP-g-MAH）复合材料,并研究其力学性能。结果表明：PP-g-MAH可提高PP与CaCO3的相容性,使复合材料的韧性和拉伸性能得到提高,PE可提高PP与POE的相容性,并有效提高复合材料的韧性,经POE、PE、CaCO3和PP-g-MAH之间的相互协同改性作用可制得综合性能优良的PP复合材料。     

POE/POE-g-MAH/PP-g-MAH增韧PP/滑石粉研究

以聚丙烯(PP)/滑石粉复合体系为基料,马来酸酐接枝聚乙烯辛烯弹性体(POE-g-MAH)、聚乙烯辛烯弹性体(POE)以及聚丙烯接枝马来酸酐(PP-g-MAH)作为增韧剂,利用双螺杆挤出机进行熔融共混,研究了不同增韧剂对共混体系的力学性能、流变性能和结晶性能,并通过XRD、红外光谱和DSC进行综合测试。实验结果表明:三种增韧剂对PP/滑石粉复合体系的性能有显著影响,综合增韧效果以PP-g-MAH为最佳。红外表征、XRD和DSC分析表明:三种增韧剂对PP/滑石粉复合体系中的PP分子链有一定相互作用。     

催化剂MnyCezOx/Al2O3催化氧化乙酸乙酯的性能

采用浸渍法制备了Mn基负载型催化剂,测定了它们催化氧化乙酸乙酯的活性以及水蒸气对其催化性能的影响,研究结果表明所制备的催化剂对乙酸乙酯都具有明显的催化活性,其中催化剂Mn0.8Ce0.2Ox/Al2O3催化氧化乙酸乙酯的活性最高,其T90仅为225℃。催化剂Mn0.8Ce0.2Ox/Al2O3的抗水蒸气影响的能力也要高于催化剂MnOx/Al2O3。     

Al/SO42-复合改性CrOx/VOx/SiO2双金属催化剂及其乙烯聚合特性研究

采用溶液浸渍及高温煅烧的方法制备了一系列Al/SO₄^2-复合改性CrO_x/VO_x/SiO₂双金属催化剂,并研究了其催化乙烯聚合特性。结果表明：采用较低的m(Al)∶m(S)改性的双金属催化剂活性较未改性催化剂提升20%～40%;改性前后催化剂均表现出稳定的聚合活性,采用改性催化剂制备的聚合物相对分子质量更高,相对分子质量分布更宽;采用改性前后催化剂制备的聚合物相对分子质量分布均呈双峰,采用改性催化剂时其超高相对分子质量部分含量有所增加,而中、高相对分子质量部分含量明显更少。上述结果为单釜高效合成双峰聚乙烯产品及聚合物相对分子质量调控提供了重要手段。     

Eu-Doped BaTiO3 Powder and Film from Sol-Gel Process with Polyvinylpyrrolidone Additive

Transparent BaTiO₃:Eu³⁺ films were prepared via a sol-gel method and dip-coating technique, using barium acetate, titanium butoxide, and polyvinylpyrrolidone (PVP) as modifier viscosity. BaTiO₃:Eu³⁺ films ~500 nm thick, crystallized after thermal treatment at 700 ºC. The powders revealed spherical and rod shape morphology. The optical quality of films showed a predominant band at 615 nm under 250 nm excitation. A preliminary luminescent test provided the properties of the Eu³⁺ doped BaTiO₃.     

An investigation on the microstructural and electrical properties of La0.85DxSr0.15–xGa0.8Mg0.2O2.825 (D = Ba and Ca) electrolytes in solid oxide fuel cells

La_0.85D_xSr_0.15–xGa_0.8Mg_0.2O_2.825 (D = Ba and Ca, x?=?0, 0.01, 0.03, 0.05, and 0.07) electrolytes were synthesized using a solid-state reaction method, calcined at 1400?°C for 5?h, and sintered at 1400?°C for 5?h. The microstructures, electrical properties, and cell performances of the electrolytes and fuel cells were analyzed by X-ray diffraction, scanning electron microscopy, impedance analysis, and electrochemical analysis. La_0.85Ba_xSr_0.15–xGa_0.8Mg_0.2O_2.825 (LBSGM) and La_0.85Ca_xSr_0.15–xGa_0.8Mg_0.2O_2.825 (LCSGM) exhibit a dense structure and a cubic perovskite phase. Further, they contain small amounts of a secondary phase. The lattice constants of LBSGM and LCSGM are 0.3913–0.3914?nm and 0.3906–0.3909?nm, respectively. The average grain size of the sample increases with increasing Ba²⁺ or Ca²⁺ content. The conductivity of LCSGM (0.197–0.174?S/cm) is usually higher than that of LBSGM (0.181–0.162?S/cm) at 800?°C. The cells with La_0.85Sr_0.15Ga_0.8Mg_0.2O_2.825 and La_0.85Ca_0.03Sr_0.12Ga_0.8Mg_0.2O_2.825 electrolytes exhibit high open-circuit voltages and maximum power densities of 0.96?V and 542?mW/cm² and 0.94?V and 567?mW/cm², respectively, at 800?°C.     

Improvement of Al3+ ion conductivity by F doping of (Al0.2Zr0.8)4/3.8NbP3O12 solid electrolyte for mixed potential NH3 sensors

New Al³⁺ ion conducting solid electrolytes (Al_0.2Zr_0.8)_4/3.8NbP₃O_12-xF_2x(0?≤x?≤?0.4) with Nasicon-structure are successfully prepared by solid state reaction method. The influences of the doped F^- content on the properties of the (Al_0.2Zr_0.8)_4/3.8NbP₃O_12-xF_2x samples are investigated using X-ray powder diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The results show that F^- doping can effectively improve the sinterability and the total conductivity of the (Al_0.2Zr_0.8)_4/3.8NbP₃O_12-xF_2x samples. Among the solids series, (Al_0.2Zr_0.8)_4/3.8NbP₃O_11.7F_0.6 shows the highest conductivity of 1.53?×?10^?3 S?cm^?1at 500?°C, which is approximately 7.9 times higher than that of the undoped (Al_0.2Zr_0.8)_4/3.8NbP₃O₁₂. The ion transference number of the samples is higher than 0.99 at 300–700?°C. On the basis of the promising properties, a mixed-potential type NH₃ sensor based on (Al_0.2Zr_0.8)_4/3.8NbP₃O_11.7F_0.6 electrolyte and In₂O₃ sensing electrode has been developed. The sensing performance of the sensor is evaluated. The mixed-potential type sensor can work at relatively low temperatures of 200–350?°C and an excellent sensitivity of 99.71?mV/decade at 250?°C is obtained. The sensor also displays excellent stability and reproducibility, accompanied by low cross-sensitivities to CO₂, CH₄ and H_2.     

In situ preparation of monodispersed Ag/polyaniline/Fe3O4 nanoparticles via heterogeneous nucleation

Acrylic acid and styrene were polymerized onto monodispersed Fe₃O₄ nanoparticles using a grafting copolymerization method. Aniline molecules were then bonded onto the Fe₃O₄ nanoparticles by electrostatic self-assembly and further polymerized to obtain uniform polyaniline/Fe₃O₄ (PANI/Fe₃O₄) nanoparticles (approximately 35 nm). Finally, monodispersed Ag/PANI/Fe₃O₄ nanoparticles were prepared by an in situ reduction reaction between emeraldine PANI and silver nitrate. Fourier transform infrared and UV-visible spectrometers and a transmission electron microscope were used to characterize both the chemical structure and the morphology of the resulting nanoparticles.     

Thermoelectric properties of Bi2O3-added WO3 ceramics

Tungsten trioxide (WO₃) ceramics were prepared by firing Bi₂O₃-added WO₃ compacts with atomic ratios of Bi/W?=?0.00, 0.01, 0.03, or 0.05, in which Bi₂O₃ was mixed as a sintering agent. Dense ceramics consisting of remarkably grown WO₃ grains were obtained for Bi-containing samples with Bi/W?=?0.01, 0.03, and 0.05. The grain growth was enhanced by the liquid phase of Bi₂W₂O₉ formed among the WO₃ grains while firing. The XRD patterns did not show evidence for Bi inclusion into the WO₃ lattice, but the SEM-EDX showed an intensive distribution of Bi into the grain boundaries. Electrical conductivity σ and Seebeck coefficient S were measured in a temperature range of 373–1073?K. The temperature dependences indicated that the Bi₂O₃-added WO₃ ceramics were n-type semiconductors. It was considered that the electron carriers were generated from oxygen vacancies included into the WO₃ grains. The thermoelectric power factors S²σ for the ceramics ranged from 1.5?×?10^?7 W?m^?1 K^?2 to 2.8?×?10^?5 W?m^?1 K^?2, and the highest value occurred at 970?K for the ceramic with Bi/W?=?0.01.     

Improved antifouling resistance of electrochemical water quality sensors based on Cu2O-doped RuO2 sensing electrode

Improvement in both sensor's characteristics and antifouling resistance has been achieved by utilising Cu₂O as a dopant to the sub-micron-sized RuO₂ sensing electrode (SE) of the water quality sensors. 20 mol% Cu₂O-doped RuO₂-SE has exhibited a linear response to dissolved oxygen (DO) between 0.5 and 8.0 ppm at various temperatures with the sensitivity slope of −46 mV/decade. This paper describes the structural properties and characteristics of thin-film Cu₂O-doped RuO₂-SE subjected to a field trial in sewerage environment for three months. Selectivity measurements revealed that the presence of PO₄³⁻, SO₄²⁻, Ca²⁺, Mg²⁺, Li⁺, NO³⁻, F⁻, Na⁺, K⁺ and Cl⁻ in the test solution had no significant effect on the sensor's emf. Long-term stability test in harsh sewerage environment demonstrated that the Cu₂O-doped RuO₂-SE possesses improved antifouling resistance compared to RuO₂-SE. Morphology and crystalline structure of Cu₂O-doped RuO₂-SE were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) technique and Raman spectroscopy.     

Powder preparation and high infrared performance of NaLaS2 transparent ceramics

NaLaS₂ powders with various Na/La molar ratios were prepared via a gas-solid reaction method where NaF nanocrystal was used as the sodium source, and CS₂ served as the sulfurizing agent. The effective sulfurization parameters were designed based on the thermodynamic properties of the precursor obtained via the reverse coprecipitation way. The phase compositions and morphologies of sulfide powders depended strongly on NaF amount. The powder with a molar ratio of Na/La = 1.3 was selected for sintering NaLaS₂ ceramic via hot-pressing process under vacuum due to its highest phase purity and lowest oxidesulfide, fluorosulfide impurities level. As-sintered NaLaS₂ ceramic exhibited a consolidated microstructure, a minor amount of oxysulfide impurities and high 8–14 μm mean transmissivity with the maximum transmittance up to 67.5% at 9 μm. Contrasting study proves that NaLaS₂ ceramic has the tendency to possess the better IR performance and antioxidation capacity than γ-La₂S₃ and CaLa₂S₄ ceramics.     

Hierarchical Cd4SiS6/SiO2 Heterostructure Nanowire Arrays

Novel hierarchical Cd₄SiS₆/SiO₂ based heterostructure nanowire arrays were fabricated on silicon substrates by a one-step thermal evaporation of CdS powder. The as-grown products were characterized using scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. Studies reveal that a typical hierarchical Cd₄SiS₆/SiO₂ heterostructure nanowire is composed of a single crystalline Cd₄SiS₆ nanowire core sheathed with amorphous SiO₂ sheath. Furthermore, secondary nanostructures of SiO₂ nanowires are highly dense grown on the primary Cd₄SiS₆ core-SiO₂ sheath nanowires and formed hierarchical Cd₄SiS₆/SiO₂ based heterostructure nanowire arrays which stand vertically on silicon substrates. The possible growth mechanism of hierarchical Cd₄SiS₆/SiO₂ heterostructure nanowire arrays is proposed. The optical properties of hierarchical Cd₄SiS₆/SiO₂ heterostructure nanowire arrays are investigated using Raman and Photoluminescence spectroscopy.     

Preparation of Al2O3-coated expanded graphite with enhanced hydrophilicity and oxidation resistance

Expanded graphite (EG), as a new kind of functional carbon-based material, is a vital supporting material and heat transfer enhancer for preparing highly conductive form-stable composite phase change materials (PCMs). However, the hydrophobic nature of EG makes it difficult to incorporate with inorganic PCMs. In this work, we intended to solve this drawback and a modified EG named Al₂O₃-coated EG which was characterized by enhanced hydrophilicity was developed via a heterogeneous nucleation technique and subsequent heat treatment. Experiments found that the Al₂O₃ layer on the surface of EG was uniform and essentially amorphous, and was well-bonded to EG via chemical interactions between oxygen atoms from Al₂O₃ and carbon atoms from EG. The hydrophilicity and oxidation resistance of Al₂O₃-coated EG could be enhanced by increasing the amount of Al₂O₃. Most importantly, compared with EG, the water contact angle of Al₂O₃-coated EG dropped from 90.7° to 33.9° when only 4.4?wt% Al₂O₃ was used, indicating that the hydrophilicity of EG could be greatly enhanced by low cost. Moreover, molecular dynamics (MD) simulation of the hydrophilicity of EG and Al₂O₃-coated EG proved that the preparation of Al₂O₃-coated EG was an efficient and feasible method to improve the hydrophilicity of EG.     

High piezoelectric coefficient of Pr2O3-doped Ba0.85Ca0.15Ti0.90Zr0.10O3 ceramics

Pr₂O₃-doped Ba_0.85Ca_0.15Ti_0.90Zr_0.10O₃ (BCTZ-xPr) ceramics were prepared by the conventional solid-state method. A tetragonal phase is only observed in these ceramics, and the introduction of Pr₂O₃ decreases their sintering temperature without affecting negatively the piezoelectric constant. Enhanced ferroelectric properties were obtained in these BCTZ-xPr ceramics. The ceramic with x=0.06 wt% exhibits a good electrical behavior of d₃₃∼460 pC/N, k_p∼47.6%, ε_r∼4638, and tan δ∼0.015 when sintered at a low temperature of ∼1400 °C. As a result, the BCTZ-xPr ceramic is a promising candidate for lead-free piezoelectric ceramics.