CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Hanqi Qian,Yue Yao,Qingyuan Cao,Tao Liu,Nan Li,Yudong Huang,Regina Maratovna Islamova,Bo Jiang
Developing coating materials, which are thermally insulating and high-strength support in extreme environments, is a hot spot for the thermal protection of aerospace. However, the lack of stable ceramic construction after prolonged thermal attack creates a risk of mechanical performance degradation. Herein, a silicon-based porous thermal protection composite was proposed by enveloping an innovative silicone resin on melamine frame. The thermostability of silicone resin was significantly improved by just 2 wt% addition of a multifunctional silane monomer, due to the incorporated diphenylamine and its derived quinonimine structure. Meanwhile, the uniform distribution of ammonium polyphosphate (APP) in the system effectively filled defects and cracks during pyrolysis. These facilitated the formation of an ordered porous polymer-derived ceramic framework under high temperature, thus significantly enhancing the material's mechanical strength (1200 °C, 3.39 MPa) and thermal insulation. Notably, even when subjected to prolonged high-temperature flame impact, the 3 mm-thick quinonimine-incorporated coating maintained its intact structure and preserved a backside temperature 77 °C lower than that of traditional silicone/melamine coating. This work provides a strategy for developing thermal protection composites that exhibit machinability, high strength, and superior thermal insulation performance in extreme environments.
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DOI
高影响因子
ANALYST
·
2015
·Vol. 140
·期 12
·4057-4067
·
IF 4.107
Wenying Fan,Mingqi Gao,Man He,Beibei Chen,Bin Hu
In this work, a molecularly imprinted polymer (MIP) coated stir bar was prepared using a self-designed polytetrafluoroethylene (PTFE) mold and in situ polymerization, with cyromazine as the dummy template for the target melamine. The prepared MIP coated stir bar presented a uniform and porous surface as well as good chemical stability and selectivity for melamine. Based on it, a method of MIP coated stir bar sorptive extraction (SBSE) combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was developed for the quantification of melamine in food samples. Significant factors affecting the extraction efficiency of melamine by MIP-SBSE, such as the extraction solvent and time, stirring rate, desorption solvent and time, were investigated thoroughly. Under the optimal conditions, the analytical performance of this method was evaluated. The detection limit of the developed method was 0.54 μg L−1 for melamine with an enrichment factor of 42-fold and the relative standard deviation (RSD) of 6.1% (c = 5 μg L−1, n = 7), and the linear range was 2–200 μg L−1. The established method was applied for the determination of melamine in a variety of real samples including cat food, dog food, chicken feed A, chicken feed B and milk powder, and the recoveries for melamine in the spiked samples were in the range of 76.2–98.2%, 80.0–85.5%, 89.5–113%, 85.0–95.5% and 65.0–111%, respectively. The proposed method presented a good specific recognition ability and matrix interference resistance, and was demonstrated to be effective and sensitive for the analysis of melamine in animal food and milk samples.
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DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2025
·
IF 4.3
Weijian Lu,Jianyu Yang,Lulu Bai,Yao-Feng Wang,Xiangping Zhang,Shaojuan Zeng
The synthesis of melamine from urea represents a pivotal industrial process, which is extensively applied fine chemicals production across various industries. However, the melamine synthesis is severely hindered by conventional catalysts with poor porosity, leading to low catalytic efficiency under harsh conditions and rapid deactivation due to mass transfer limitations. Herein, a series of novel mesoporous Beta zeolite catalysts with tunable porosity and acidity were designed and fabricated for melamine synthesis through a piperidine assisted-desilication strategy. The introduction of piperidine effectively mitigated framework desilication of zeolite crystals under OH – attack, while enabling precise tuning of mesoporosity (increasing S ext from 25 to 126 cm 2 g −1 and V mes from 0.151 to 0.433 cm 3 g −1 ) and acidity (enhancing total acid sites from 0.52 to 1.14 mmol g −1 ) by modulating piperidine addition during desilication process. Among the prepared Beta zeolites, mesoporous B-7P sample (piperidine/SiO 2 molar ratio of 0.07) exhibited exceptional catalytic performance, achieving 72.3% melamine yield under mild condition (400 °C, 0.4 MPa), which represented a 67% and 15% enhancement over commercial Beta zeolite and industrial catalyst, respectively. This excellent performance could be attributed to the synergistic combination of increased active sites and well-developed mesopores that facilitating intra-crystal molecular diffusion and improved the accessibility of active centers in pores. Besides, B-7P zeolite also showed excellent recyclability (>98.5% of initial activity) over five consecutive cycles, and exhibited superior coke resistance due to its optimized pore architecture, demonstrating exceptional potential as an advanced catalyst for melamine production.
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Zhuohao Xie,Peng Li,Haonan Zhan,Liuyan Zhuang,Sijian Tao,Liehua Deng,Jiahao Huang
Efficient and accurate detection of melamine in dairy products remains a crucial yet challenging task. Herein, an allosterically modulated G-quadruplex-integrated aptamer is rationally designed with thymine-rich recognition termini for melamine binding. The detection process is facile by simply introducing the analyte into the mixture consisting of G-quadruplex aptamer probes, exonuclease III, and thioflavin T (ThT). The detection feasibility is confirmed by the polyacrylamide gel electrophoresis and fluorescence measurement results. This exonuclease III-assisted signal amplifiable approach works well in a linear range from 0.1 nM to 0.1 μM. Moreover, a detection limit as low as 83 pM is easily achieved, which is almost five orders of magnitude smaller than the maximum allowable melamine levels (about 8 μM) defined by many countries all over the world. The whole assay time for each test is no longer than 1 h. Additionally, the scheme is highly specific and satisfactory recovery rates (from 91% to 104%) are readily obtained when challenged with melamine-spiked milk samples. Therefore, the label-free, turn-on, low-cost, and time-efficient method can be used for reliable detection of melamine in an easily manipulated and ultra-sensitive manner, which may find its utilization in the field of food safety, biomedical engineering, and clinical diagnosis.
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DOI
PubMed
高影响因子
Catalysts
·
2020
·Vol. 10
·期 5
·575
·
IF 3.52
Luqian Zhang,Chen Wang,Jing Sun,Zhengkai An
Benzene is a typical volatile organic compound (VOC) and is found widely in industrial waste gases. In this study, trimesoyl chloride-melamine copolymer (TMP)-TiO2nanocomposites with excellent photocatalytic efficiency in visible-light degradation of gas-phase benzene were synthesized via an in situ hydrothermal synthesis. The optimal conditions for TMP-TiO2nanocomposite synthesis were determined by orthogonal experiments. The structural, physiochemical, and optoelectronic properties of the samples were studied by various analytical techniques. Ultraviolet-visible diffuse reflectance spectroscopy and surface photovoltage spectra showed that the positions of the light-absorbance edges of the TMP-TiO2nanocomposites were sharply red-shifted to the visible region relative to those of unmodified TiO2. The most efficient TMP-TiO2nanocomposite was used for photocatalytic oxidative degradation of gas-phase benzene (initial concentration 230 mg m−3) under visible-light irradiation (380–800 nm); the degradation rate was 100% within 180 min. Under the same reaction conditions, the degradation rates of unmodified TiO2(hydrothermally synthesized TiO2) and commercial material Degussa P25 were 19% and 23.6%, respectively. This is because the Ti–O–N and Ti–O–C bonds in TMP-modified TiO2reduce the band gap of TMP-TiO2. The amide bonds in the TMP decrease the TiO2nanoparticle size and thus increased the specific surface area. The conjugated structures in the TMP provide abundant active sites for trapping photogenerated electrons and promote the separation and transfer of photogenerated electrons and holes.Keywords:TiO2;visible light;volatile organic compound;benzene;gas degradation
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2018
·
IF 5.091
Peihua Wen,Yadong Wang,Ni Wang,Shengwen Zhang,Bo Peng,Ziwei Deng
A facile and environmentally friendly approach was proposed to decorate Ag nanoparticles on melamine-formaldehyde (MF) colloidal particles (MF/Ag composite microspheres). In this approach, monodisperse MF colloidal particles were prepared via a two-step organic sol-gel process and served as the active templates for the decoration of Ag nanoparticles. Then, the [Ag(NH 3 ) 2 ] + ions as the Ag precursors can be adsorbed onto the surfaces of the MF colloidal particles and were in situ reduced into metallic Ag nanoparticles, forming MF/Ag composite microspheres . During this synthesis, neither presurface activation nor extra reductants were necessary. These MF/Ag composite microspheres can be used as the surface-enhanced Raman scattering (SERS) active substrates for the trace detection of organic compounds, e.g., 4-aminobenzenethiol (4-ABT) and penicillin G sodium. Furthermore, these MF/Ag composite microspheres also showed excellent antibacterial activities against both Escherichia coli ( E. coli , gram-negative bacteria) and Staphylococcus aureus ( S. aureus, gram-positive bacteria).
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DOI
高影响因子
ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Xiaowei Mu,Jing Zhan,Xiaming Feng,Bihe Yuan,Shuilai Qiu,Lei Song,Yuan Hu
Covalent organic frameworks (COFs) nanosheets prepared from condensation reaction between melamine and o-phthalaldehyde are first prepared through ball milling and then incorporated into thermoplastic polyurethanes (TPU) by solution mixing. Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectrometer are applied to characterize COFs nanosheets. It is observed apparently from TEM image that COFs nanosheets are obtained. Successful preparation of COFs nanosheets is proved further by vanishment of typical diffraction peak of COFs at around 23.5° in COFs nanosheets XRD pattern, appearance of quadrant and semicircle stretching of the s-triazine ring at 1568 and 1469 cm–1 in FTIR spectra and N═C bond at 389.5 eV in N1s high-resolution XPS spectra of COFs nanosheets. The thermal property, combustion behavior and mechanical performance of TPU naoncomposites are also investigated. Incorporation of COFs nanosheets into TPU contributes to char forming of TPU under nitrogen atmosphere and 14.3% decrease of peak heat release rate of TPU. Besides, the elongation at break, Young’s modulus, and fracture strength of TPU nanocomposites increase sharply compared with that of neat one.
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高影响因子
ChemSusChem
·
2020
·Vol. 13
·期 7
·1834-1843
·
IF 7.962
Jingwei Zhu,Benlin He,Zekun Gong,Yang Ding,Wenyu Zhang,Xueke Li,Zhihao Zong,Haiyan Chen,Qunwei Tang
Graphical Against the grain : Adding melamine maximizes grain size and minimizes defects in CsPbBr 3 perovskite films. The resulting CsPbBr 3 perovskite solar cell (PSC) free of encapsulation achieves a champion power conversion efficiency (PCE) of 9.65 % and excellent thermal and humidity stability. The preparation of high-quality perovskite films with low grain boundaries and defect states is a prerequisite for achieving high-efficiency perovskite solar cells (PSCs) with good environmental stability. An effective additive engineering strategy has been developed for simultaneous defect passivation and crystal growth of CsPbBr 3 perovskite films by introducing 1,3,5-triazine-2,4,6-triamine (melamine) into the PbBr 2 precursor solution. The resultant melamine–PbBr 2 film has a loose, large-grained structure and decreased crystallinity, which has a positive effect on the crystallization process of the perovskite as it retards the crystallization rate as a result of the interaction between melamine and lead ions. Additionally, the passivation by melamine gives a high-quality CsPbBr 3 perovskite film with fewer grain boundaries, lower defect densities, and better energy level matching is achieved by multistep liquid-phase spin-coating, which greatly suppresses the nonradiative recombination resulting from the defects and promotes charge extraction at the interface. A champion power conversion efficiency as high as 9.65 % with a promising open-circuit voltage of 1.584 V is achieved for PSCs with an architecture of fluorine-doped tin oxide/c-TiO 2 / m -TiO 2 /melamine-added CsPbBr 3 /carbon-based hole-transporting layer. Furthermore, the unencapsulated melamine-added CsPbBr 3 PSC shows superior thermal and humidity stability in ambient air at 85 °C or 85 % relative humidity over 720 h.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 137
·期 2
·47298
·
IF 1.901
Wei Hou,Yifan Fu,Cen Zeng,Na Liu,Cuiyu Yin
In this study, the nanocomposites are prepared which used polyamide 6 (PA6) composite as matrix, melamine cyanurate (MCA) as fire retardant and attapulgite (AT) as synergistic agent. The mathematical model between MCA content, AT content, and limited oxygen index (LOI) is established by multiple linear regression fitting. The polymer materials are characterized using Fourier transform infrared spectroscopy, X-ray diffraction, Thermogravimetric Analysis, and scanning electron microscopy. Through response surface methodology, the important variables (polymerization time, the content of MCA, and the content of AT) affecting the mechanical strength of composites are modeled. Results demonstrate that when the t is 0.6 h, the AT content is 6.2%, and the MCA content is 11.5%, the mechanical properties of the PA6/MCA/AT composite are up to 44.81 MPa, and the sample passes the UL-94 V-0 flammability rating, and the LOI reaches 27.9%. Therefore, polymers with highly effective flame retardancy and optimal mechanical properties are prepared. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 47298.
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高影响因子
JOURNAL OF POROUS MATERIALS
·
2023
·Vol. 30
·期 6
·1937-1951
·
IF 2.6
Liang Jiaming,Lin Shaohui,Feng Xianshe,Pan Qinmin
Frequent oil spills and oily wastewater discharge have caused serious damage to the ecological environment, which make it urgent to address these challenges. Herein, we report an effective strategy and low-cost method to transform commercially available melamine foams into superhydrophobic/superoleophilic absorbents, which has a high separation ability for both oil-water mixtures and emulsions. Our approach involves the co-deposition of tannic acid and 3-aminopropyltriethoxysilane on the foam surface to form a hierarchical structure, followed by the covalent grafting of palmitic acid with low surface energy onto the foam backbones via acylation. The resulting foam maintained a cross-linked porous structure with a water contact angle of 153° and a sliding angle of 7°, exhibiting a high degree of water repellency. Absorption experiments with chloroform and engine oil showed that the foam has high absorption capacity, reaching 99.2 and 172.8 times its own weight, respectively, and the foam still retains excellent elasticity after 1000 compression cycles. In addition, the superhydrophobic foam has a high demulsification ability to oil-in-water emulsions by repeated compression and violent stirring, and its separation ability for toluene-in-water emulsions was up to 99.25%. Based on these results, the superhydrophobic foam has significant potential for large-scale oil spill cleanup and wastewater purification.
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DOI
高影响因子
Journal of Macromolecular Science Part B-Physics
·
2021
·
IF 1.504
Hengyu Feng,Qingshi Cui,Yu Zhou,Jinglong Dong,Ming Li,Linghan Xiao,Yuhui Ao
Understanding the mechanism of thermal degradation of a material may suggest a promising way for further improving its thermal properties. poly(melamine-co-phenolic resin) (P(M-co-PR)) has been widely used in flame resistant and fire-proof materials. Our characterization of the thermal degradation of P(M-co-PR) is described in this work. Fourier-transform infrared (FTIR) and X-ray photo-electron spectroscopy (XPS) analyses were used to investigate the structural evolution during the thermal degradation of the copolymer. The evolutions of C = N and C-N bonding in heteroaromatic rings were monitored during the degradation process by C1s and N1s XPS spectra. The degradation processes of P(M-co-PR) is divided into three stages. The degradation kinetics of P(M-co-PR) was researched by using the Ozawa and Kissinger activation energy equation methods. The conclusion is that the Kissinger equation applied to the first stage, and the Ozawa equation applied to the second and third stages.
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DOI
高影响因子
Science China-Materials
·
2020
·Vol. 64
·期 5
·1150-1158
·
IF 6.098
Chen Jing,Pan Anqiang,Zhang Wenchao,Cao Xinxin,Lu Rou,Liang Shuquan,Cao Guozhong
Noble metal-free electrocatalysts with high activity are highly desirable for the large-scale application of hydrogen evolution reaction (HER). Mo 2 C-based nanomaterials have been proved as a promising alternative to noble metal-based electrocatalysts owing to the Pt-resembled d-band density and optimal intermediates-adsorption properties. However, the aggregation and excessive growth of crystals often occur during their high-temperature synthesis procedure, leading to low catalytic utilization. In this study, the ultrafine Mo 2 C/Mo 2 N heterostructure with large surface and interface confined in the N-doped carbon nanofibers (N-CNFs) was obtained by a melamine-assisted method. The synergistic effect of Mo 2 C/Mo 2 N heterostructure and plenty active sites exposed on the surface of ultrafine nanocrystals improves the electrocatalytic activity. Meanwhile, the N-CNFs ensure fast charge transfer and high structural stability during reactions. Moreover, the in-situ synthesis method strengthens the interfacial coupling interactions between Mo 2 C/Mo 2 N heterostructure and N-CNFs, further enhancing the electronic conductivity and electrocatalytic activity. Owing to these advantages, Mo 2 C/Mo 2 N@N-CNFs exhibit excellent HER performance with a low overpotential of 75 mV at a current density of 10 mV cm −2 in alkaline solution, superior to the single phased Mo 2 C counterpart and recently reported Mo 2 C/Mo 2 N based catalysts. This study highlights a new effective strategy to design efficient electrocatalysts via integrating heterostructure, nanostructure and carbon modification.
研究领域:
材料科学
·
电化学
·
纳米技术
·
能量转换
·
催化
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高影响因子
危险品化学品经营许可证（带存储）