POLYHEDRON
·
2017
·
IF 1.926
Ling-Dong Chen,Lin-Xia Zhou,Yue-Qing Zheng,Hong-Lin Zhu
Two new supramolecular complexes [Ag 2 (MA) 2 (2-nbd)]·2.5H 2 O ( 1 ) and [Ag 2 (MA) 2 (3-npa)]·2H 2 O ( 2 ) (2-H 2 nbd = 2-nitroterephthalic acid; MA = melamine; 3-H 2 npa = 3-nitrophthalic acid) have been synthesized under ultrasound conditions and characterized by infrared spectra (IR), thermogravimetric analysis (TGA), elemental analyses (EA) and X-ray diffraction (XRD). Complex 1 exhibits 2D framework through the bridging of carboxylic acid ligand and melamine ligand. Complex 2 presents a binuclear silver structural unit, which was further construct to three-dimension structure via hydrogen-bond interaction. The photocatalytic performance and photoluminescent properties of them were also investigated. And the results show that complex 1 and 2 exhibited good photocatalytic activity towards the degradation of Rhodamine B (RhB) and Methylene Blue (MB) under visible light irradiation. Moreover, it is verified that the degradation rate fits the first-order kinetics.
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COMPOSITES SCIENCE AND TECHNOLOGY
·
2016
·
IF 3.897
Min Zhao,Linghui Meng,Lichun Ma,Guangshun Wu,Fei Xie,Lina Ma,Wei Wang,Bo Jiang,Yudong Huang
A practical method for growing generation 1–3 melamine-based dendrimers onto carbon fibers (CFs) surface was proposed. The microstructures and interfacial properties of CFs before and after modification were investigated. X-ray photoelectron spectroscopy (XPS) confirmed the successful growth of different generation dendrimers. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images showed that melamine-based dendrimers grafting enhanced surface roughness , and this effect was more pronounced with increasing generation. The results of dynamic contact angle (DCA) demonstrated that the surface energy and the wettability of the grafted CFs were increased with generation. After generation 3 dendrimers grafting, the interfacial shear strength (IFSS) and impact strength of CF/epoxy composites were enhanced by 61.8% and 39.9%, respectively. The tensile strength of the composites were enhanced as the generation increased. Moreover, the reinforcing and toughening mechanisms were also discussed.
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SENSORS AND ACTUATORS B-CHEMICAL
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2016
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IF 4.758
Ning Dong,Yongjun Hu,Kang Yang,Jianzhi Liu
Herein, we developed a novel nanosenor to detect trace amount of melamine (M) in the milk using aptamer-modified surface-enhanced Raman scattering (SERS) nanosensor and oligonucleotide chip. The SERS nanosensor was prepared by attaching Raman tag and ploy-thymine (T) aptamer to the gold nanoparticles, respectively. SERS nanosensor can be absorbed to the oligonucleotide chip with a high specificity where a “T–M–T” structure via multi-hydrogen-bond could be formed between the melamine molecule and the thymine molecule. In the measurement, the Raman signal intensities obtained from the chip increase when the concentrations of melamine in solutions increase. The proposed method allows us to detect melamine with a limit of 1.0 ppt (1.0 pg mL −1 ), which is fall far below the strictest safety limit. Compared with the previous methods, the sensitivity of this sensor shows about 100-fold improvement. The advantages of the present sensor are its low detection cost and the simplified sample pretreatment. Furthermore, the reliable and enough accurate results have been obtained by the using of the proposed nanosensor in the assay of trace melamine in real milk sample.
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Food Analytical Methods
·
2016
·Vol. 10
·期 5
·1386-1396
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IF 2.167
Wang Yu,Gao Lei,Qin Dongli,Chen Ligang
In this work, a simple and selective method based on matrix solid phase dispersion (MSPD) using molecularly imprinted polymers (MIPs) as sorbents was successfully developed for the determination of melamine (MEL) in milk powder. The MIPs have been prepared by surface imprinted polymerization method using carbon nanotube (CNT) as support, MEL as template molecule, γ-aminopropyltriethoxysilane as functional monomer, and tetraethyl orthosilicate as cross-linking agent. The MIPs were characterized by Fourier transform infrared spectrometer and scanning electron microscopy. At the same time, the adsorption isotherm, dynamic adsorption, and selective adsorption of MIPs to MEL were also studied. The prepared MIPs were used as dispersant of MSPD to extraction and separate MEL in milk powder. We optimized the extraction conditions as follows: the ratio of MIPs to sample was 2:3; the dispersion time was 10 min; washing solvent was 2.0 mL acetonitrile; and elution solvent was 4.0 mL ammonium methanol (5:95, v / v ). Once the MSPD process was completed, the MEL extracted from milk powder was determined by LC-MS/MS. Under the optimal conditions, the limit of detection of MEL was 0.2 ng g −1 . The relative standard deviations of intra-day and inter-day were obtained in the range of 0.4∼5.1 %. The satisfied recoveries of MEL were 92.5∼97.2 %. The MIP-MSPD method has some advantages, such as higher selectivity, lower cost of preparation, less time consuming and organic solvent consumption, simpler sample pretreatment procedure, and higher extraction recovery compared with those existing methods which were used for determination of MEL.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
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IF 2.8
Tao Wang,Jiajia Ye,Shuning Liu,Xiaobo Liu,Lifen Tong
Melamine-based benzoxazine resins overcome the disadvantages of conventional polybenzoxazine, such as high brittleness and difficult processing. However, the reactivity is too high to be easily processed. In this work, phenolphthalein-type melamine-based benzoxazine (PTma-BG) was synthesized from paraformaldehyde, phenolphthalein, melamine, and benzeneguanoamine. The chemical structure of PTma-BGs was characterized by fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance ( 1 H NMR), and the curing behavior and properties of the resulting polymers were verified. The results demonstrate that the incorporation of benzeneguanoamine facilitates the formation of the oxazine ring while simultaneously reducing the reactivity of the PTma-BGs precursor, prolonging the gelation time, and expanding the processing window. Poly(PTma-40BG) has good thermal stability; it has been observed that the T d5 of Poly(PTma-40ma) reaches 328°C, which is higher than that of Poly(PTma). Furthermore, Poly(PTma-BG)s demonstrate exceptional heat resistance, with a glass transition temperature exceeding 285°C. The introduction of benzeneguanoamine results in a reduction in the number of polar groups, which in turn leads to a decrease in both water absorption and dielectric constant.
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OPTICAL MATERIALS
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2024
·
IF 3.8
Xingqun Zhu,Rai Nauman Ali,Ming Song
In this work, sol-gel method is employed to prepare ZnO nanoparticles with different surface defect states. Simultaneously, the prepolymer solution of melamine resin (MF) is also pre-synthesized. Then the as-prepared ZnO nanoparticles are mixed with prepolymer solution of melamine resin, resulting in the multi-colored solid-state photoluminescence phosphors (ZnO NPs@MF) after heat curing and grinding. The enhanced fluorescence emission is observed for ZnO NPs@MF, which may be due to the local field effect and reduction of non-radiative transitions brought by the dispersion and coating of MF resin. In addition, we have applied blue ZnO NPs@MF phosphors to the white light emitting diodes (LED) device, which preliminarily confirms the possibility of using our synthesized fluorescent powder in the indoor light source .
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POLYMER DEGRADATION AND STABILITY
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2024
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IF 6.3
Zhishuo Liu,Yifang Hua,Suqin Liu,Hongfei Li,Xiaoyu Gu,Jun Sun,Sheng Zhang
In this study, a novel approach was employed to enhance the flame retardant efficiency of an intumescent flame retardant (IFR) by growing a layered double hydroxides (LDHs) of Zn/Fe on the surface of melamine polyphosphate (MPP), denoted as Zn/Fe-LDH@MPP (LDHMPP). This modification was carried out via in-situ co-precipitation, and the resulting composite was subsequently applied to polypropylene (PP) in conjunction with piperazine pyrophosphate (PAPP). Under the same proportion and concentration, the PP/16 %LDHIFR formulation achieved a preferred V-0 rating in the UL-94 test. Furthermore, this formulation exhibited an enhanced ability to form a protective char layer, as evidenced by both cone calorimetry tests (CCT) and thermogravimetric analysis (TGA) tests. Additionally, the synergistic effect of Zn/Fe-LDH on flame retardancy was also studied.
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JOURNAL OF CHROMATOGRAPHY A
·
2025
·
IF 4
Hanwen Deng,Yue Wang,Xiaoyu Chen,Meiling Zhou,Yike Huang,Min Wang,Zhining Xia
Based on the principle that poly(thymine) could recognize melamine (Mel) in aqueous media and the third face of Mel could be accessed by other hydrogen bonding molecules, UiO-66-NH 2 was functionalized with poly(thymine) ssDNA and as the matrix to construct three-face recognition molecularly imprinted polymers (UDMIPs). The adsorption processes of UDMIPs towards Mel were accorded to Sips model and exhibited high adsorption capacity (Q S =10.60 mg/g) and good imprinting factor (IF=2.67). UDMIPs could reach the adsorption equilibrium within 20 min. Competitive adsorption and regeneration experiments demonstrated that UDMIPs exhibited good selectivity and reusability. The adsorption machanism was investigated by CD spectroscopy. Combined with HPLC, UDMIPs were successfully employed to detect Mel in milk samples with recovery rates ranging from 88.4% to 94.8%.
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PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2009
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IF 3.756
Jia Li,Huan-Yang Qi,Yan-Ping Shi
News stories about the contamination of milk with melamine in China emerged on Sept 11, 2008, and the situation has since become an international health scare. In this work, a novel analytical method based on enrichment and pretreatment of analytes in the milk sample, hollow fiber sorptive extraction and gas chromatography–mass spectrometry has been developed for the rapid analysis of melamine in the dairy products. In the proposed method, melamine in the fresh milk was extracted by zirconia hollow fiber, enriching on zirconia coating of the hollow fiber, and then analyzed by GC–MS. The method validations including linearity, limit of detection, limit of qualification, recoveries at three different concentrations, precision, and repeatability were investigated. It was found that the proposed method provided linear range from 0.001 to 1000 μg/mL ( r 2 = 0.9997), low detection limit of 0.001 μg/mL, and preferable recoveries at three different concentrations. The obtained results demonstrated that zirconia hollow fiber combined with GC–MS is a simple, rapid and solvent-free method for the analysis of melamine in the dairy products.
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PubMed
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2024
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IF 9.4
Debin Cai,Shuai Wu,Zhen Tian,Li Guo,Yanzhong Wang
The self-assembled aerogels are considered as an efficient strategy to address the aggregation and restacking of Ti 3 C 2 T x MXene nanosheets for high-performance supercapacitors. However, the low mechanical strength of the MXene aerogel results in the structural collapse of the self-standing supercapacitor electrode materials. Herein, a low-cost melamine sponge (MS) absorbed different cations (H + , K + , Mg 2+ , Fe 2+ , Co 2+ , Ni 2+ and Al 3+ ), serves as a carrier and crosslinker for loading MXene hydrogel induced by the absorbed cations on the skeleton surface and the pores of MS, resulting in the high loading mass MXene aerogels with high mechanical strength. The experimental results show that the Mg-Ti 3 C 2 T x @MS aerogel exhibits the maximum area capacitance of 702.22 mF cm −2 at 3 mA cm −2 , and the area capacitance is still 603.12 mF cm −2 even at 100 mA cm −2 , indicating the high rate capability with a capacitance retention of 85.89 %. It is worth noting that the constructed asymmetric supercapacitor with activated carbon achieves high energy densities of 104.53 μWh cm −2 and 93.87 μWh cm −2 at 800 μW cm −2 and 7999 μW cm −2 , respectively. Furthermore, the asymmetric supercapacitor shows the high cycling stability with 90.2 % capacity retention after 10,000 cycles. This work provides a feasible strategy to prepare Ti 3 C 2 T x MXene aerogels with large layer spacing and high strength for high-performance supercapacitors.
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Energy Storage Materials
·
2024
·
IF 18.9
Xin Wang,Hui Peng,Kanjun Sun,Fan Yang,Zhiyuan Liu,Shuzhen Cui,Xuan Xie,Guofu Ma
Aqueous zinc (Zn)-based energy storage devices have attracted great attention due to their inherent low cost, intrinsic safety, and environmental friendliness. However, the growth of Zn dendrite and side reactions from water decomposition have limited the lifespan of Zn-ion energy storage. Herein, a green and multifunctional melamine (M) molecules is proposed as electrolyte additive and incorporated into the ZnSO 4 electrolyte to modulate the deposition/stripping environment of Zn 2+ and stabilize the Zn anode. The results of experiments coupled with density-functional theory (DFT) calculations and molecular dynamics (MD) simulations show that M molecules are able to optimize the electrolyte environment and regulate the electrode-electrolyte surface. More specifically, the hydrophilic group (-NH 2 ) in the M molecule can effectively break the electrolyte sheath structure and reconstruct the hydrogen bonding network, because the M molecule has a stronger binding energy compared to H 2 O. Meanwhile, the -N= groups in M can anchor Zn 2+ and cooperate with them to form a dynamic electrostatic protective layer, change the electric field distribution around the Zn deposition layer, provide more nucleation sites for Zn 2+ and promote the deposition of Zn along the (002) crystal plane, thus inhibiting the random growth of Zn dendrite and the occurrence of side reactions. Consequently, the Zn//Zn symmetric cell assembled with the ZnSO 4 +M electrolyte presents boost the stable lifespan over 1,100 hours at a current density of 2 mA cm −2 , 1 mAh cm −2 , and also up to 1900 stable cycles with almost 100 % Coulomb efficiency for Zn//Cu asymmetric cell.
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PROGRESS IN ORGANIC COATINGS
·
2024
·
IF 6.5
Penglun Zheng,Haihan Zhao,Yawei Meng,Junwei Li,Qizhao You,Quanyi Liu
Epoxy resin (EPs) coatings for aircraft need to have good flame retardant properties and toughness. On the other hand, to meet the needs of sustainable development, EPs also have high environmental friendliness and low cost requirements. In light of this, a one-pot approach was used to create a bio-based phosphorus‑nitrogen synergistic flame retardant (MDV) employing DOPO, vanillin, and MA as raw materials. The results showed that MDV can give EP superb flame retardancy and toughness. With the addition of 3 wt% MDV, the tensile and flexural strengths of EP composites increased by 13.6 % and 14.5 %, respectively, and the impact strength increased from 13.9 KJ/m 2 to 43.1 KJ/m 2 . The excellent toughness enhancement comes from the fact that the structure of MDV itself can preferentially consume and dissipate energy when counteracting external impacts. In addition, MDV/EP also has excellent flame retardant properties, showing good self-extinguishing capability off fire in tests. Compared with pure EP, the total heat release (THR) and peak heat release rate (PHRR) of 7-MDV/EP composites were reduced by 45.3 % and 64.5 %, respectively. Mechanistic analyzes showed that the segregation of the condensed phase and the gas-phase flame-retardant effect both originated from the P/N synergistic effect, which was the source of the excellent flame-retardant effect of MDV/EP.
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