Advanced polymeric composites via commingling for critical engineering applications

The commingled technology is one of the most effective and alternative methodologies for producing more sustainable as well as uniformly distributed natural fiber reinforced composite without inflecting the shearing strength on yarns or reinforcing natural fiber. The term commingled encompasses the materials consisting of both polymer matrix and reinforcing materials over the same fabric cross-section used for the production of highly flexible, continuous fiber-reinforced thermoplastic prepregs. Nonetheless, the increased pathlength and high melt viscosity around 500–5000 Pa s of the molten thermoplastic makes the processing more difficult compared with other thermoset plastic (usually 100 Pa s). Where the commingled hybrid yarns can be considered as one of the promising preforms employed for long fiber reinforced composite because of low cost, ease of storage and manipulation, excellent flexibility, molding capacity, reduced pressure consolidation as well as impregnation time while processing and the ability to form complex-shaped reinforced composite parts. The parameters that affect the process of commingling controls the consolidation of hybrid yarns thermoplastic composite; the degree of commingling depends on the pressure, temperature, and production speed during a fixed period. Recently commingled thermoplastic composite has become one of the possible destines for a wide array of applications in aircrafts, automotive, and sporting goods. This paper reviews types of commingled plastic composite, various processing routes, and the influence of the processing parameters, their properties, and their application. The manufacturing and development of hybrid yarns through air-jet texturing, intermingling process, are also discussed concerning the attributes of advanced composites.     

采用甲烷燃料的管状固体氧化物燃料电池浸渍阳极电化学性能

以NiO和8％（摩尔分数）氧化钇稳定的氧化锆为原料,采用注凝成型工艺制备了管状同体氧化物燃料电池阳极支撑体．用离子浸渍法对阳极支撑体进行表面修饰．用电化学工作站测单电池交流阻抗和输出性能并且用化学气相色谱仪对电池尾气进行分析．测试结果表明修饰后的阳极在通甲烷的情况下出现了一定程度的积炭,但是积炭现象在一定的测试时间内达到平衡,没有对电池造成破坏,并且显著地提高了电池阳极的电化学性能．单电池存通入氯气和甲烷的情况下最大输出功率密度分别达到了225和400mW／cm^2．     

Optimization of the electrochemical performance of a Ni/Ce0.9Gd0.1O2−δ-impregnated La0.57Sr0.15TiO3 anode in hydrogen

A-site deficient perovskite La_0.57Sr_0.15TiO₃ (LSTO) materials are synthesized by a modified polyacrylamide gel route. X-ray diffraction pattern of LSTO indicates an orthorhombic structure. The thermal expansion coefficient of LSTO is 10.0 × 10⁻⁶ K⁻¹ at 600 °C in 5%H₂/Ar. LSTO shows an electrical conductivity of 2 S cm⁻¹ at 600 °C in 3%H₂O/H₂. A new composite material, containing the porous LSTO backbone impregnated with small amounts of Ce_0.9Gd_0.1O_2−δ (CGO) (3.4–8.3 wt.%) and Ni/Cu (2.0–6.3 wt.%), is investigated as an alternative anode for solid oxide fuel cells (SOFCs). Because of the substantial electro-catalytic activity of the fine and well-dispersed Ni particles on the surface of the ceramic framework, the polarization resistance of 6.3%Ni-8.3%CGO-LSTO anode reaches 0.73 Ω cm² at 800 °C in 3%H₂O/H₂. In order to further improve the anodic performance, corn starch and carbon black are used as pore-formers to optimize the microstructure of anodes.     

Functionalization of polymeric membranes by impregnation and in situ cross-linking of a PDMS/β-cyclodextrin network

In this paper a new method for the functionalization of porous membranes with β-CD is reported. Porous polypropylene (PP) hollow fibres have been impregnated with a mixture composed by a partially cross-linked polydimethylsiloxane (PDMS) and β-cyclodextrin (β-CD). The prepolymerization of the PDMS components was necessary to avoid their inclusion in the β-CD cavity. The firm heterogenization of the β-CD was obtained by in situ cross-linking of the PDMS/β-CD network in the porous membranes. The presence of the PDMS/β-CD network in the membranes was confirmed by FT-IR-ATR (on the outer and inner surfaces) and EDX analyses (on the cross-section).The effect of the impregnation times on membrane morphology, loading and porosity has been investigated. The binding capacity of the heterogenized β-CDs has been tested using the phenolphthalein as guest molecule.     

负载Ni金属有序介孔氧化铝催化剂的制备及表征

采用原位合成法和传统浸渍法以价格低廉的硝酸铝作为铝源, 聚乙二醇1540为模板剂, 硝酸镍为镍源, 制备出负载Ni金属有序介孔氧化铝催化剂, 并采用BET、TEM、XRD、TG多种测试技术对合成催化剂的物理化学性质和结构特征进行了表征. 实验结果表明, 两种方法均能制备出比表面积大(＞210 m2·g-1)、孔径分布窄(4 nm左右)的负载Ni金属介孔氧化铝催化剂. 与浸渍法相比, 原位合成法所制备的负载Ni金属有序介孔氧化铝镍离子与载体具有更强的相互作用力, 且孔结构具有一定的有序性.     

Thermal regeneration of activated carbons saturated with ortho- and meta-chlorophenols

Activated carbons (ACs) made from peach and plum stones were oxidized and impregnated with salts of Cu(II), Fe(III), Ni(II) and Cr(III). The chemically modified ACs, along with a commercial AC (S208c), were saturated with ortho- (OCP) and meta-chlorophenol (MCP) to investigate the potential for thermally regenerating the spent ACs. The thermal regeneration process was monitored by thermal analysis (TGA/DSC), gas chromatography and mass spectrometry (GC/MS). Thermal desorption profiles showed that in most cases weight losses occur in two steps (weak physisorption at ∼220 °C and strong chemisorption at ∼620 °C). Intermediate steps at ∼400 °C appeared in samples whose chemical treatments successfully weakened the interactions between strongly chemisorbed chlorophenol (CP) molecules and AC surfaces. The type and quantity of products of OCP and MCP desorption during the thermal regeneration of a spent AC depend on the chemical modification given to the AC prior to its use as CP adsorbent. Besides the original chlorophenols, thermal regeneration products can include chlorobenzene, dichloro-dibenzofuran, phenol, aliphatic and aromatic hydrocarbons, water, chlorides, carbon oxides, hydrogen, and char deposits. Mechanisms for the formation of these compounds are discussed. The char deposits built during this study did not appear to diminish the surface area or porosity of the chemically modified ACs following their thermal regeneration.     

镍基催化剂的制备、表征及选择加氢性能

研究了溶胶-凝胶-超临界流体干燥法（sol-gel-SCFD）和浸渍法（IM）制备的SiO2负载镍催化剂的顺酐液相加氢性能,并用XRD、TPR、IR等手段对催化剂的体相和表面结构进行了表征.结果表明: 1) Sol-Gel-SCFD法制备的催化剂其体相和表面结构与镍含量有关,当镍含量 < 30％(质量分数)时,NiO主要以簇团形式存在;随镍含量增高到50％,过量的NiO以微晶态存在并覆盖部分NiO簇团.顺酐(MA)加氢产物有丁二酸酐(SA)和γ-丁内酯(γ-BL),它们的选择性随镍含量增加呈规律性变化;在镍含量为30％的催化剂上γ-BL选择性呈现最大值. 2) IM法制备的催化剂其体相和表面结构与镍含量无关,当镍含量在6％～30％范围内变化时,NiO都以结晶态存在,MA加氢产物为SA; NiO与SiO2的相互作用随镍含量增加而减弱,SA的选择性不变.     

(La0.8Sr0.2)0.9MnO3–Gd0.2Ce0.8O1.9 composite cathodes prepared from (Gd, Ce)(NO3) x -modified (La0.8Sr0.2)0.9MnO3 for intermediate-temperature solid oxide fuel cells

Development of high performance cathodes with low polarization resistance is critical to the success of solid oxide fuel cell (SOFC) development and commercialization. In this paper, (La_0.8Sr_0.2)_0.9MnO₃ (LSM)–Gd_0.2Ce_0.8O_1.9(GDC) composite powder (LSM ~70 wt%, GDC ~30 wt%) was prepared through modification of LSM powder by Gd_0.2Ce_0.8(NO₃) _x solution impregnation, followed by calcination. The electrode polarization resistance of the LSM–GDC cathode prepared from the composite powder was ~0.60 Ω cm² at 750 °C, which is ~13 times lower than that of pure LSM cathode (~8.19 Ω cm² at 750 °C) on YSZ electrolyte substrates. The electrode polarization resistance of the LSM–GDC composite cathode at 700 °C under 500 mA/cm² was ~0.42 Ω cm², which is close to that of pure LSM cathode at 850 °C. Gd_0.2Ce_0.8(NO₃) _x solution impregnation modification not only inhibits the growth of LSM grains during sintering but also increases the triple-phase-boundary (TPB) area through introducing ionic conducting phase (Gd,Ce)O_2-δ, leading to the significant reduction of electrode polarization resistance of LSM cathode.     

Cu改性SAPO-11分子筛催化萘和甲醇甲基化反应的研究

分别采用水热合成法和浸渍法对SAPO-11分子筛进行Cu改性.通过X射线衍射(XRD)、扫描电镜(SEM)、NH_3-程序升温脱附(NH_3-TPD)、H_2-程序升温还原(H_2-TPR)、~(29)Si固体核磁共振(~(29)SiMAS NMR)以及N_2吸附-脱附(N_2adsorption-desorption)等表征手段对改性前后SAPO-11分子筛的结构、酸性进行表征,并研究了改性后分子筛催化合成2,6-二甲基萘反应性能的影响规律.结果表明,经水热合成法进行Cu改性的SAPO-11分子筛结晶度升高,酸中心数量增加,比表面积和孔体积上升,从而使萘的转化率、2,6-二甲基萘的选择性、2,6-二甲基萘与2,7-二甲基萘的比值及2,6-二甲基萘的收率提高.     

Sono-synthesis and characterization of bimetallic Ni–Co/Al2O3–MgO nanocatalyst: Effects of metal content on catalytic properties and activity for hydrogen production via CO2 reforming of CH4

Sono-dispersion of Ni, Co and Ni–Co over Al₂O₃–MgO with Al/Mg ratio of 1.5 was prepared and tested for dry reforming of methane. The samples were characterized by XRD, FESEM, PSD, EDX, TEM, BET and FTIR analyses. In order to assess the effect of ultrasound irradiation, Ni–Co/Al₂O₃–MgO with Co content of 8% prepared via sonochemistry and impregnation methods. The sono-synthesized sample showed better textural properties and higher activity than that of impregnated one. Comparison of XRD patterns indicated that the NiO peaks became broader by increasing Co content over the support. The FESEM images displayed the particles are small and well-dispersed as a result of sonochemistry method. Also, EDX analysis demonstrated better dispersion of Ni and Co as a result of sonochemistry method in confirmation of XRD analysis. The sono-synthesized Ni–Co/Al₂O₃–MgO as a superior nanocatalyst with Co content of 3% illustrates much higher conversions (97.5% and 99% for CH₄ and CO₂ at 850 °C), yields (94% and 96% for H₂ and CO at 850 °C) and 0.97 of H₂/CO molar ratio in all samples using an equimolar feed ratio at 850 °C. During the 1200 min stability test, H₂/CO molar ratio remained constant for the superior nanocatalyst.