Polymers
·
2018
·Vol. 10
·期 12
·1362
·
IF 2.935
Bo Xu,Yuwei Liu,Jiugang Yuan,Ping Wang,Qiang Wang
Hydrogels with outstanding mechanical performance, self-healing capacity, and special functionality are highly desirable for their practical applications. However, it remains a great challenge to achieve such hydrogels by a facile approach. Here, we report a new type of nanocomposite hydrogels by in situ copolymerization of acrylic acid (AA) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) using alumina nanoparticles (Al2O3NPs) as the cross-linkers. The obtained hydrogels are highly stretchable and compressible, which could sustain large-scale extension (>1700%) or compression (90%) without failure, and exhibit tensile and compressive strength up to 660 kPa and 8.3 MPa, respectively. Furthermore, this kind of hydrogel also display considerable self-healing capacity due to their noncovalent cross-linking mechanism, as well as the hydrogen-bonding interactions between polymer chains. More interestingly, it was found that the resultant gels possess a long-lasting antifogging property that could prevent the formation of fog on the glass plate above hot water for at least 90 min. It is expected that this novel type of hydrogel would show great promise for various applications, including soft robots, artificial muscles, and optical devices.Keywords:nanocomposite hydrogels;Al2O3;high-strength;self-healing;antifogging
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PubMed
高影响因子
ADVANCED ENGINEERING MATERIALS
·
2019
·Vol. 21
·期 9
·1900458
·
IF 2.906
Qingliang Shan,Qinglei Wang,Yudong Xue,Jianbao Hu,Jinshan Yang,Haijun Zhou,Guangxiang Zhu,Shaoming Dong
Aluminum oxide is introduced into SiC f /(SiC + B 4 C) composites to improve the surface cracking resistance after oxidizing at 1100 °C in O 2 /H 2 O (40/60) atmosphere. Research on morphology observation of oxidized composites reveals that Al 2 O 3 can lead to the formation of a dense and smooth oxidation layer, resulting in a relatively shallow oxygen penetration depth. In-depth studies on acoustic emission reveal that composites with Al 2 O 3 can improve the surface cracking resistance after oxidizing at 1100 °C in O 2 /H 2 O (40/60) atmosphere since the retention rates of σ min (first acoustic emission [AE] stress) and σ onset (AE onset stress) are significantly increased compared with virgin composites. Moreover, a small number of cumulative events and steep slope of strength–time curves at the initial stage further confirm the improvement of surface cracking resistance after oxidation.
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高影响因子
RSC Advances
·
2019
·Vol. 9
·期 19
·10702-10714
·
IF 3.049
Cunlong Li,Yuqing Zhang,Ming Yong,Wei Liu,Jiaqi Wang
In order to effectively clean oily seawater with anionic polyacrylamide (APAM), UiO-66 coated γ-Al2O3 (UA) composites were firstly synthesized using γ-Al2O3 as a template to induce the growth of high hydrophilic UiO-66 on its surface to form a uniform UA self-assembled membrane. The UA composites and self-assembled membrane were characterized and analyzed. Also, the membrane performance was investigated. The results show that the hydrophilicity of particles is enhanced with the water contact angle decreasing from 39.8° (γ-Al2O3 particles) to 26.2° (UA composites) by introducing the UiO-66 coating. Moreover, the UA self-assembled membrane performs attractive water yield and separation performance. The oil concentration in the permeate treated by the first class of UA self-assembled membrane declines apparently from 91.22 to 18.90 mg L−1, while the water yield is as high as 657.89 L m−2 h−1. The reclaimed separation experiments show that the membrane materials could be recycled by calcination at 200 °C and hydraulic cleaning, which gives the material potential application in cleaning oily seawater.
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高影响因子
CATALYSIS LETTERS
·
2018
·Vol. 148
·期 11
·3402-3412
·
IF 2.911
Bao Qiang,Qi Hui,Zhang Chunlei,Ning Chunli,Zhang Yi,Jiang Ye,Wu Yifan,Gui Wenying,Wang Zhenlu
Abstract In this work, titanium-doped mesoporous Al 2 O 3 (γ-Ti–Al 2 O 3 ) was prepared by an evaporation-induced self-assembly method and used as a carrier of Ba/γ-Ti–Al 2 O 3 catalyst to catalyze the aldol condensation of methyl acetate with formaldehyde to methyl acrylate in a fixed-bed reactor. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, N 2 adsorption–desorption, pyridine absorption performed via Fourier transform infrared spectroscope (Py-IR), and NH 3 and CO 2 temperature-programmed desorption (NH 3 and CO 2 -TPD). Experimental results indicated that the doping of the titanium species into the frame work of mesoporous Al 2 O 3 (γ-Ti–Al 2 O 3 ) had a significant influence on the catalytic activity via modifying the acid–base surface properties of the catalyst. Furthermore, the Ba/γ-Ti–Al 2 O 3 catalyst demonstrated excellent catalytic performance, with a methyl acetate conversion rate of 50% and methyl acrylate selectivity up to 90.2%. Compared with the Ba/Al 2 O 3 catalyst, the Ba/γ-Ti–Al 2 O 3 catalyst had better catalytic activity, stability and potential for practical application, which was likely due to an increased number of Lewis acid sites, especially the medium acid sites. Graphical Abstract Barium supported mesoporous γ-Ti–Al 2 O 3 catalyst was found to be an effective catalyst for vapor phase aldol condensation of methyl acetate with formaldehyde.
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高影响因子
KEY ENGINEERING MATERIALS
·
2018
·
IF 0
Wu Lei,Ben Ma,Jian Pu,Chi Bo,Li Jian
As the ceramic substrate materials in automobile oxygen sensor, 5YSZ/Al2O3 matrix composite ceramic with different amount of silica are prepared by ball-milling,tape casting and sintering.They are investigated for their microstructure and mechanical properties.The microstructure of the sample is analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX).Fracture strength is measured by ring-on-ring method. It is found that adding 1 wt.% SiO2 into 5YSZ/Al2O3 matrix can improve the strength of composite ceramics.
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SOLAR ENERGY
·
2018
·
IF 4.374
Huajun Chen,Wenjie Tian,Wuxiu Ding
Metallic sliver-doped mesoporous Al 2 O 3 fibers (meso-Ag/Al 2 O 3 ) that can harvest visible light to speed up solar water purification, were synthesized by one-pot hydrothermal method. Insightful analyses of XRD, XRF and XPS of meso-Ag/ Al 2 O 3 verified that metallic silver occupied interstitial positions of Al 2 O 3 lattice forming interstitial solid solution. N 2 adsorption/desorption illustrated that meso-Ag/Al 2 O 3 exhibited significantly increases in the specific surface area, pore volume and average pore diameter after doping with silver. The UV–Vis diffuse reflectance spectra and disinfection performance indicated that meso-Ag/Al 2 O 3 can harvest visible light to promote the conversion of dioxygen to ROS for water disinfection compared with the widely used TiO 2 . With our approach, we achieved water disinfection of >99.999% inactivation of bacteria in 120 min with a small amount of material (8 mg/L) under simulated visible light.
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高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Lini Zhu,Sifan Zeng,Zhen Teng,Heng Luo,Xiaochun Han,Chen Chen,Wanlin Feng,Yongqiang Tan,Haibin Zhang
Macroscopic parallel aligned non-woven carbon fibers were incorporated into Al 2 O 3 composites in this study to evaluate the contribution of multiple reflections to the total electric magnetic interference (EMI) shielding. Results indicate that parallel aligned non-woven carbon fiber layers contribute significantly to the total EMI shielding effectiveness (SE T ) of Al 2 O 3 composites by largely enhancing the EMI absorption, and seven parallel aligned thin non-woven carbon fiber layers finally make the almost microwave-transparent Al 2 O 3 an excellent EMI shielding material with an EMI SE T as high as 29–32 dB in the X-band frequency range. The volume fraction of carbon fibers in Al 2 O 3 composites with seven carbon fiber layers is calculated to be only 0.5%, and therefore the EMI SE enhancement efficiency by parallel aligned large non-woven carbon fiber layers is much higher than other highly conducting nano fillers. It validates the significance of multiple reflections in achieving high EMI shielding properties in ceramic composites and provides an instructive approach to design efficient EMI shielding ceramic composites.
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MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2017
·
IF 3.094
Xiaoyao Qu,Fucheng Wang,Chunsheng Shi,Naiqin Zhao,Enzuo Liu,Chunnian He,Fang He
An aluminium matrix composite reinforced by in situ-generated gamma-Al 2 O 3 whiskers was fabricated from a simple Al-H 3 BO 3 system through cold pressing and sintering. The gamma-Al 2 O 3 whiskers with an average diameter of 20 nm and an aspect ratio of 10–15 were synthesized during the sintering process and homogeneously distributed in the Al matrix. As a result of the perfect lattice matching between gamma-Al 2 O 3 and the Al matrix, the gamma-Al 2 O 3 whisker is a desired reinforcement for the Al matrix, improving the ultimate tensile strength and hardness to 217 MPa and 43.5 HV, respectively, with a satisfactory ductility of 11%. Differential scanning calorimetry analysis shows that the growth of the whisker occurred at 550–650 °C, and the ball milling energy has a significant effect on whisker growth.
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高影响因子
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
·
2016
·Vol. 34
·期 4
·
IF 1.724
Duan Chen-Long,Deng Zhang,Cao Kun,Yin Hong-Feng,Shan Bin,Chen Rong
Iron(II,III) oxide (Fe 3 O 4 ) nanoparticles have shown great promise in many magnetic-related applications such as magnetic resonance imaging, hyperthermia treatment, and targeted drug delivery. Nevertheless, these nanoparticles are vulnerable to oxidation and magnetization loss under ambient conditions, and passivation is usually required for practical applications. In this work, a home-built rotating fluidized bed (RFB) atomic layer deposition (ALD) reactor was employed to form dense and uniform nanoscale Al 2 O 3 passivation layers on Fe 3 O 4 nanoparticles. The RFB reactor facilitated the precursor diffusion in the particle bed and intensified the dynamic dismantling of soft agglomerates, exposing every surface reactive site to precursor gases. With the aid of in situ mass spectroscopy, it was found that a thicker fluidization bed formed by larger amount of particles increased the residence time of precursors. The prolonged residence time allowed more thorough interactions between the particle surfaces and the precursor gas, resulting in an improvement of the precursor utilization from 78% to nearly 100%, even under a high precursor feeding rate. Uniform passivation layers around the magnetic cores were demonstrated by both transmission electron microscopy and the statistical analysis of Al mass concentrations. Individual particles were coated instead of the soft agglomerates, as was validated by the specific surface area analysis and particle size distribution. The results of thermogravimetric analysis suggested that 5 nm-thick ultrathin Al 2 O 3 coatings could effectively protect the Fe 3 O 4 nanoparticles from oxidation. The x-ray diffraction patterns also showed that the magnetic core crystallinity of such passivated nanoparticles could be well preserved under accelerated oxidation conditions. The precise thickness control via ALD maintained the saturation magnetization at 66.7 emu/g with a 5 nm-thick Al 2 O 3 passivation layer. This good preservation of the magnetic properties with superior oxidation resistance will be beneficial for practical magnetic-based applications.
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高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2016
·Vol. 34
·期 1
·41-53
·
IF 1.408
Rong Jian,Zhang Tao,Qiu Fengxian,Chen Mingliang
Hierarchical porous NiO/Al 2 O 3 composites were successfully prepared by two-steps. First, the core-shell structured Al 2 O 3 microspheres were prepared via a template-free hydrothermal route using KAl(SO 4 ) 2 ·12H 2 O and Al 2 (SO 4 ) 3 ·18H 2 O as aluminum source. Then, the NiO/Al 2 O 3 composites with micro- and nano-hierarchical structures were prepared by a hydrothermal method combining the subsequent calcination process. The obtained characterization result presented that the morphology of hierarchical Al 2 O 3 microsphere tuned to irregular platelets by simply varying Ni/Al ratios. The BET analysis showed that the special surface area from 52.12m 2 g −1 to 214.8m 2 g −1 after two hydrothermal complex process. Effects of Ni/Al ratio, adsorbent dosage, Congo red (CR) concentration, coexisting ions, adsorption time and temperature were investigated. The obtained results indicated that NiO/Al 2 O 3 composite had the high adsorption efficiency (99.6%) and great adsorption capacity (186.9mg g −1 ) under the optimum conditions. The adsorption isotherm and kinetics data were found to be well fitted and in good agreement with the Langmuir isotherm model and pseudo-second order model, respectively. The hierarchical porous NiO/Al 2 O 3 composites presented remarkably higher adsorption efficiency during five recycling, which showed their potential as the highly efficient adsorbent for removal of CR in wastewater.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Shao-jia Liu,Fa-tang Li,Yi-lei Li,Ying-juan Hao,Xiao-jing Wang,Bo Li,Rui-hong Liu
The mismatches of lattices and energy bands in heterojunction are the dominant factors restricting the generation efficiency of reactive oxygen species (ROS) that are powerful tools for water purification and anti-bacteria. In this paper, the mediated lattice matching role of amorphous Al 2 O 3 is presented for constructing the ternary g-C 3 N 4 /Al 2 O 3 /ZnO heterojunctions, which exhibit higher molecular oxygen activation performance than binary g-C 3 N 4 /ZnO and g-C 3 N 4 /Al 2 O 3 heterojunctions. The oxygen activation ability and the ROS generation were testified by the electron paramagnetic resonance (EPR) measurement, transformation of nitroblue tetrazolium (NBT) and degradation of methylene blue (MB). The ROS include superoxide anion radical ( O 2 − ) and consequent product of hydroxyl radical ( OH). The superior oxygen activation performance of the ternary heterojunctions can be attributed to the lattices matching of the mediated amorphous Al 2 O 3 and the resultant efficient cascade electron transfer.
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JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2014
·
IF 3.679
Yuming Cui,Na Liu,Yifen Xia,Jiangang Lv,Sujuan Zheng,Nianhua Xue,Luming Peng,Xuefeng Guo,Weiping Ding
1-Butene, abundant but inexpensive in industry, can be used to produce more valuable propene and ethene through the well-known metathesis reaction. In terms of catalyst system of molybdena, controlling the interaction between the molybdena and the support is quite crucial. A special support, i.e., well-shaped one-dimensional γ-Al 2 O 3 with uniform diameters of ∼10 nm and lengths of ∼100 nm, has been synthesized via oleylamine-assisted hydrothermal method. The molybdenum oxides are well controlled in sizes of moderate aggregation suitable for 1-butene metathesis with a fairly high rate of propene production (38.9 × 10 −9 mol m −2 s −1 , 30 mol% yield in a single pass) under mild conditions. The status of MoO x species in the catalyst has been investigated by solid state 29 Si MAS NMR, Raman, UV–vis, H 2 -TPR and NH 3 -TPD techniques. The catalyst, highly stable after twelve times of regeneration, is important for practical utilization for the metathesis reactions.
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