POLYMER DEGRADATION AND STABILITY
·
2014
·
IF 2.633
Guang-Rui Xu,Miao-Jun Xu,Bin Li
The cyclotriphosphazene-based epoxy resin hexa-[4-(glycidyloxycarbonyl) phenoxy]cyclotriphosphazene defined as CTP-EP was successfully synthesized from hexachlorocyclotriphosphazene, p -hydroxybenzaldehyde and epichlorohydrin. Its chemical structure was characterized by Fourier transform infrared (FTIR) spectroscopy, 1 H NMR, 13 C NMR and 31 P NMR spectroscopy . The prepared compound was cured with diamino diphenyl methane (DDM), diamino diphenyl sulfone (DDS) and m -phenylenediamine (mPDA), respectively. The flame retardant properties, thermal degradation behavior and flame retardant mechanism of the cured CTP-EP were investigated. The LOI values of all cured CTP-EP samples increased from 19.9% for cured diglycidyl ether of bisphenol-A (DGEBA) to above 30% and successfully passed UL-94 V-0 rating, which demonstrated that the prepared CTP-EP thermoset exhibited excellent flame retardancy. The dynamic mechanical thermal analysis (DMA) test demonstrated that the glass transition temperature ( Tg ) enhanced from 155 °C for the cured DGEBA to 167 °C for CTP-EP thermoset . The results of thermogravimetric analysis/infrared spectrometry (TG-IR) tests suggested that the phosphazene group and high aromatic content in CTP-EP thermoset stimulated the dehydration of the matrix at earlier degradation process and the formation of char layer, which retarded the release of pyrolysis gas and enhanced the thermal stability of the cured CTP-EP at high temperature. The cone calorimeter tests (cone) test revealed that heat release rate (HRR), total heat release (THR), smoke production rate (SPR) and total heat production (TSP) of the cured CTP-EP decreased significantly compared with the cured DGEBA. The scanning electron microscopy (SEM) results showed that the phosphazene groups in CTP-EP obviously stimulated the formation of the intumescent, compact and stable char layer, which enhanced the flame retardancy of the matrix during combustion. Consequently, the underlying materials were protected from further degradation and combustion during a fire and result in the efficient flame retardancy of CTP-EP thermoset.
研究领域:
高分子化学
·
材料科学
·
热分析
·
阻燃材料
·
聚合物化学
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·Vol. 11
·期 12
·9868-9880
·
IF 1.5
Hongying Li,Xueliang Wang,Tao Wang,Zhaoxia Wang,Wei Zhao
A modified electrode was fabricated by casting graphene oxide (GO) suspension onto the surface of active glassy carbon electrode (GCE), and it can significantly enhanced the oxidation peak currents of m-trihydroxybenzene (m-THB) and p-nitrophenol (p-NP). Based on this, a sensitive analytical method towards their simultaneous determination was established. Many influencing factors such as the type of electrolyte, acidity, scan rates and concentrations were explored. Under the optimal experimental conditions, the oxidation peak currents of m-THB and p-NP were linearly increased with their concentrations ranging from 9 to 100 μM, with the detection limits both of 1 μM. Comparing with other reported methods, this sensor showed wider linear range and lower detection limit. In addition, the proposed method was successfully used to analysis of real environmental water samples with satisfactory recoveries, which verified the practicability of the sensor.
研究领域:
分析化学
·
环境科学
·
电化学
·
传感器技术
·
污染物检测
✓ 已验证
DOI
高影响因子
Materials Today Communications
·
2021
·
IF 3.383
Daifeng Wu,Rui Li,Tai Sun,Renheng Tang,Fangming Xiao
Mg/MgH 2 as a thermochemical energy storage (TCES) material suffers from a slow hydrogenation-dehydrogenation kinetic and poor reversibility. Addition of metal oxide is an effective way to improve the kinetic properties of Mg/MgH 2 . However, there is little study on the effects of complex oxides . Thus, the catalytic effects of complex metal oxides and its catalytic mechanism were investigated in this paper. Results show that the dehydrogenation peak temperature and apparent activation energy of MgH 2 -Ta 2 O 5 are 320.8 °C and 128.54 kJ/mol. Combined with complex metal oxide, MgH 2 -Ta 2 O 5 -Nd 2 O 3 could further reduce the dehydrogenation peak temperature (307.2 °C) and apparent activation energy (95.33 kJ/mol). MgO and NdH 2.61 are found in the dehydrogenated MgH 2 -Ta 2 O 5 -Nd 2 O 3 , indicating that n-typed oxide Ta 2 O 5 and p-typed oxide Nd 2 O 3 are formed and improved the kinetics properties of MgH 2 . Furthermore, Nd 2 O 3 /Ta 2 O 5 interface is formed and acted as “p-n junction”. When heating, the “p-n junction” is exposed to thermal radiation and produce electrons and holes, and then the kinetics properties of MgH 2 are further enhanced.
研究领域:
材料科学
·
能源化学
·
物理化学
·
无机功能材料
·
热能存储
✓ 已验证
DOI
高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 3.371
Liya Zhou,Xucong Luo,Jiaojiao Li,Li Ma,Ying He,Yanjun Jiang,Luyan Yin,Liya Gao
The meso-molding three-dimensionally ordered macroporous alumina (3DOM/m-Al) was synthesized via a dual-templating approach (polystyrene (PS) colloidal crystals as hard template and triblock copolymer P123 as soft template) with hydrous aluminum isopropoxide as precursor. The obtained 3DOM/m-Al was characterized, and the results showed that 3DOM/m-Al had ordered macropores ( ca. 300 nm in diameter) with wormhole-like mesopores, relatively high surface areas (338.1 m 2 /g), large pore volumes (0.4030 cm 3 /g) and tunable pore sizes. The amino functionalized 3DOM/m-Al by aminopropyltriethoxysilane (APTES) was activated by glutaraldehyde and used as support for the immobilization of three different commercial enzymes (Lipase B from Candida antarctica (CALB), penicillin G acylase (PGA) and nitrile hydratase (NHase)). The result of confocal laser scanning microscopy (CLSM) indicated that the enzyme was successfully immobilized onto glutaraldehyde-activated NH 2 -3DOM/m-Al. The effect of the immobilized conditions on the specific activity of enzymes was investigated. Compared with free enzymes, the immobilized enzymes exhibited enhanced thermal stability. The three immobilized enzymes (CALB@NH 2 -3DOM/m-Al, PGA@NH 2 -3DOM/m-Al and NHase@NH 2 -3DOM/m-Al) were applied for the synthesis of palmitic acid, 6-aminopenicillanic acid (6-APA) and acrylamide, respectively. After recycling 10 times, CALB@NH 2 -3DOM/m-Al, PGA@NH 2 -3DOM/m-Al and NHase@NH 2 -3DOM/m-Al retained approximately 76%, 87% and 52% of their initial activities, respectively, indicating that the immobilized enzymes had good operational stability. Therefore, this work documented herein provides a versatile platform for enzyme immobilization with several inherent advantages.
研究领域:
材料科学
·
生物催化
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纳米材料
·
酶工程
·
多孔材料
✓ 已验证
DOI
高影响因子
MICROCHIMICA ACTA
·
2010
·Vol. 171
·期 3
·385-392
·
IF 2.648
Yin Huanshun,Zhou Yunlei,Liu Tao,Cui Lin,Ai Shiyun,Qiu Yanyan,Zhu Lusheng
An amperometric biosensor for nitrite was prepared by immobilizing cytochrome c (Cyt c) on a gold electrode that was modified with Nafion and a Cu-Mg-Al layered double hydroxide (Cu-LDH). The Cu-LDH was characterized by Fourier transform infrared spectroscopy and powder X-ray diffraction. The UV-visible spectrum suggests that Cyt c retains its native conformation in the modified film. The direct electrochemical investigation indicated that the composite film represents a good platform for the immobilization of Cyt c as well as an excellent promoter for the electron transfer between Cyt c and the gold electrode. Moreover, the biosensor showed a remarkable bioelectrocatalytic activity for the oxidation of nitrite with a linear range from 0.75 to 123 μM. The detection limit is 2 × 10 −7 M (S/ N = 3). The biosensor was successfully applied to the determination of nitrite in food samples.
研究领域:
生物分析化学
·
电化学传感
·
食品分析
·
生物传感器
·
分子诊断
✓ 已验证
DOI
高影响因子
JOM
·
2019
·Vol. 72
·期 6
·2245-2249
·
IF 2.305
Zhang Yannan,Zhang Yingjie,Li Xue,Liu Jiaming,Zhang Mingyu,Yang Xi,Huang Mengyang,Xu Mingli,Dong Peng,Zhou Zhongren
The molten salt electrolytic method was introduced to prepare metallic silicon that simply utilizes SiO 2 powder as the raw material and equimolar CaCl 2 -NaCl as the electrolyte under 1.8 V current at 700°C for 5 h.
The electrochemically synthesized silicon was in the form of nanowire structures with average sizes of 90 nm in diameter and over 1 μm in length. The current efficiency and specific energy consumption of producing silicon nanowires were calculated to be 79.2% and 8.703 kWh/kg, respectively. Benefiting from the synthesized nanowire structure, the silicon anode exhibited a high initial discharge-specific capacity of 3348.1 mAh/g with an initial coulombic efficiency of 85.2%.
The present research provides a straightforward idea to show the feasibility of synthesizing silicon-based material by the molten salt electrolytic method and to introduce the application of synthesized silicon nanowires to lithium-ion battery systems.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
无机合成
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2017
·
IF 2.714
Zhilin Xi,Zhenya Feng,Ang Li
For the control of pulverized coal, we propose a dust suppressant by applying a blend of mixed polyethylene oxide (g-PEO) and sodium dodecyl sulfate ( SDS ). In our experimental study, the thermal characteristics, critical micelle concentration ( CMC ), wettability and adhesion of the dust suppressant are investigated. It was found that g-PEO had a low fusing temperature and its combustion temperature was close to that of coal, thus, the solution containing g-PEO applied coal dust control did not affect the use of the coal. Based on steady-state fluorescence using pyrene as a fluorescent label, quantitative analysis revealed that the CMC s of g-PEO and SDS were 1 and 20 g/L in g-PEO& SDS solution, respectively. The solution containing SDS had the best wettability, but it only had a short-term effect. The solution containing g-PEO showed negligible wetting ability to wet coal dust. The solution containing g-PEO& SDS had better wetting ability and adhesion. Scanning electron microscopy showed that the coal dust covered by g-PEO& SDS on its surface could form a thin layer of armor by holding the particles together after air-drying. It was concluded that the g-PEO& SDS solution containing g-PEO for 1 g/L and SDS for 20 g/L could suppress coal dust and maintain a long-term effect.
研究领域:
环境工程
·
矿业安全
·
颗粒物控制
·
表面化学
·
燃烧科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Shaosuo Bing,Jiaqian Wang,Hao Xu,Yanyan Zhao,Yong Zhou,Lin Zhang,Congjie Gao,Li’an Hou
Polyamide (PA) thin-film composite (TFC) reverse osmosis membrane is widely used for desalination , but the selectivity-permeability trade-off and oxidation are two major restrictions on the membrane application. By modifying PA TFC membrane with potassium persulfate (K 2 S 2 O 8 ), we overcame the trade-off relation (the water flux and salt rejection increased by 43.2% and 0.2%, respectively) and improved the chlorine resistance. The modification was demonstrated to be a combination of the interfacial crosslinking between PA layer and polysulfone support with the surficial oxidation of PA layer. The dense crosslinked interface enabled the membrane with higher solute rejection, better chlorine tolerance and long-term stability. Meanwhile, the thinner PA layer contributed to the increase of membrane permeability. Furthermore, the modification method has the application potential in high-performance membrane fabrication in terms of simplicity and high efficiency.
研究领域:
材料科学
·
膜分离技术
·
高分子化学
·
环境工程
·
水处理
✓ 已验证
DOI
高影响因子
MICROCHIMICA ACTA
·
2011
·Vol. 174
·期 1
·41-46
·
IF 2.578
Wang Yinling,Peng Wei,Liu Lin,Tang Min,Gao Feng,Li Maoguo
A strategy is presented for doping graphene into layered double hydroxide films (LDHs) as a means of improving charge transport of the LDH film in a modified glassy carbon electrode. This result in an enhanced electrocatalytic current for dopamine (DA) and a good separation of the potentials of DA, uric acid and ascorbic acid. Under selected conditions, the square wave voltammetric response of the electrode to DA is linear in the concentration range from 1.0 to 199 μM even in the presence of 0.1 mM ascorbic acid, and the detection limit is 0.3 μM at a signal-to-noise ratio of 3. The method was applied to the determination of DA in pharmaceutical injections with satisfactory results.
A strategy is presented for doping graphene into layered double hydroxide films (LDHs) as a means of improving charge transport of the LDH film in a modified glassy carbon electrode. This result in an enhanced electrocatalytic current for dopamine (DA) and the square wave voltammetric response of the electrode to DA is linear in the concentration range from 1.0 to 199 μM with the detection limit of 0.3 μM. The method was applied to the determination of DA in pharmaceutical injections with satisfactory results.
研究领域:
分析化学
·
电化学
·
生物传感器
·
纳米材料
·
药物分析
·
神经化学
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·Vol. 11
·期 8
·7066-7075
·
IF 1.5
Jiheng Ding,Hongran Zhao,Lin Gu,Shengpei Su,Haibin Yu
This paper reports the synthesis of waterborne epoxy phosphate emulsion (WEP) through the reaction between epoxy resin E44 and phosphoric acid and ammonia neutralization. Synthesized WEP was characterized by FTIR for the confirmation of reaction between epoxy groups and phosphoric acid and SEM for morphology. WEP acted as a modifier in two-component epoxy anticorrosion coating on rusty steel substrate. The anticorrosion properties of the coating on rusty steel were investigated by electrochemical impedance spectroscopy (EIS) and Tafel polarization curve. Tafel polarization curve revealed that waterborne epoxy coating containing WEP had better protection ability which is clearly reflected by the protection efficiency (96.6%). EIS study also showed the higher impedance value for WEP containing coating as compared to pure waterborne epoxy coating.
研究领域:
材料科学
·
腐蚀与防护
·
高分子化学
·
表面工程
·
电化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 82
·67247-67257
·
IF 3.84
Huilong Guo,Yinwen Li,Jian Zheng,Jianqun Gan,Liyan Liang,Kun Wu,Mangeng Lu
In this work, a novel epoxy monomer denoted as 3,5′-di-t-butyl-5,3′-dimethyl biphenyl diglycidyl ether (t-BuMBPDGE) was synthesized and applied into in situ composites with 3,3′,5,5′-tetramethyl-4,4′-biphenyl diglycidyl ether (TMBPDGE), accompanied with curing agent aromatic amines. The liquid crystalline phase structure and the crosslink density of substituted biphenyl epoxies were determined by polarized optical microscopy, wide angle X-ray diffraction measurements and dynamic storage moduli data. The samples showed good mechanical properties and could recover quickly from a second state to their initial states with a shape fixity ratio higher than 98% and shape recovery ratio higher than 99%, owing to the oriented structure and increased crosslink network density caused by the orientation of biphenyl mesogenic. The high glass transition temperatures ranging from 160 to 178 °C and good water resistance could contribute to a stable fixed shape. The water resistance is analyzed by contact angles test. The samples exhibited contact angles of 92–98 degrees, which indicated that the water resistance was apparently better than that of conventional epoxy systems.
研究领域:
高分子材料
·
功能材料
·
化学工程
·
材料科学
·
纳米复合材料
·
智能材料
✓ 已验证
DOI
高影响因子
Nano Energy
·
2017
·
IF 12.343
Haoxiang Yu,Hua Lan,Lei Yan,Shangshu Qian,Xing Cheng,Haojie Zhu,Nengbing Long,Miao Shui,Jie Shu
Hollow microstructure always exhibits some special properties in the field of electrochemistry . Here, this study reports the rational design and preparation of TiNb 2 O 7 nanofibers with one dimensional hollow structure via co-electrospinning. The as-electrospun TiNb 2 O 7 hollow nanofibers show high intercalation potential, low charge-charge resistance and fast electrochemical kinetics . The electrochemical results exhibit that the TiNb 2 O 7 hollow nanofibers deliver a reversible capacity of 210.1 mAh g −1 after 150 cycles at a current rate of 0.4 C, and 158.4 mAh g −1 after 900 cycles even at a current rate of 10 C with an outstanding capacity retention of 80.6%. The excellent electrochemical performance of nanofibers can be related to the unique morphology of hollow structure. Furthermore, the lithium ions storage mechanism of TiNb 2 O 7 hollow nanofibers is also systematically analyzed, which is related to one two-phase coexistence and two solid-solution processes during the whole charge-discharge cycle. In addition, it is also demonstrated by in situ and ex situ observations that TiNb 2 O 7 hollow nanofibers have outstanding structural stability and electrochemical reversibility. Therefore, the TiNb 2 O 7 hollow nanofibers can be applied as an alternative promising electrode material for the next rechargeable lithium ions batteries .
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
无机功能材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）