Journal of Coatings Technology and Research
·
2019
·Vol. 16
·期 6
·1715-1725
·
IF 1.584
Yang Danqi,Zhang Chong,Dong Luming,Hou Xudong,Zheng Weikang,Xu Jianzhong,Ma Haiyun
A nanorod-structured strontium hydroxystannate [SrSn(OH) 6 ] flame retardant was synthesized via a facile coprecipitation method and employed in epoxy resin (EP). Based on X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy, the as-synthesized SrSn(OH) 6 nanorods exhibited high crystallinity and uniform size distribution. The flame retardancy and smoke suppression properties of EP/SrSn(OH) 6 composites were investigated by limiting oxygen index and cone calorimetry tests. The results showed that incorporation of SrSn(OH) 6 led to a dramatic reduction of the fire hazards of EP, including a 21.9% maximum decrease in the peak heat release rate, a 33.3% reduction in the toxic CO yield, and a 133.3% increase in the char residue. In particular, this is the first attempt to evaluate the flame retardancy properties of SrSn(OH) 6 nanorods in EP. The improved flame retardancy properties of the SrSn(OH) 6 nanorods is attributed to their catalytic carbonization effect.
研究领域:
材料科学
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高分子化学
·
火灾安全工程
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高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Bingjing Tao,Weifeng Wang,Huanyu Liu,Tianxiu Du,Haitao Wu,Chunfang Xing,Dongzhi Wang,Yuping Zhang
Li 4 Mg 3 [Ti 0 · 6 (Mg 1/3 Nb 2/3 ) 0.4 ] 2 O 9 (LMT 0.6 (MN) 0.4 O) ceramics doped with 1–5 wt% lithium fluoride (LiF) were prepared through a conventional solid-state reaction at a relatively low sintering temperature . The influences of the LiF additive on the micromorphology, crystal phase composition, and sintering behavior, as well as the microwave dielectric properties of the LMT 0.6 (MN) 0.4 O ceramics were explored in depth. The addition of the LiF sintering additive reduced the densification temperature of the LMT 0.6 (MN) 0.4 O ceramics from 1450 °C–950 °C. X-ray powder diffractometer patterns indicated that a single phase formed for all experimental samples. Scanning electron microscopy photographs revealed that dense and homogeneous microstructures were obtained at 950 °C for the LMT 0.6 (MN) 0.4 O ceramics with 3–5 wt% LiF. Additionally, the optimized microwave dielectric properties, including ε r = 16.24, Q·f = 107,828 GHz (at 8.13 GHz), and τ f = −6.25 ppm/°C were achieved in the prepared LMT 0.6 (MN) 0.4 O ceramics with 4 wt% LiF at the sintering temperature of 950 °C. Furthermore, the excellent chemical compatibility between this component and silver were confirmed based on the results of XRD and EDS analyses, suggesting that the LMT 0.6 (MN) 0.4 O ceramics with 4 wt% LiF could be a suitable material for the application of low temperature co-fired ceramics.
研究领域:
材料科学
·
陶瓷
·
微波工程
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Lianjun Song,Xueyu Wang,Dongqi Wang,Qian Xiao,Haowei Xu,Qiuju Li,Lanlan He,Songdong Ding
The synthesis, Eu 3+ complexation, and selective solvent extraction of Am 3+ over Eu 3+ in nitric acid solution by 2-carboxamido-6-(1 H -pyrazol-3-yl)-pyridines (A-PzPy) ligands were described. Without the aid of any lipophilic anion source, A-PzPy ligands in methyl isobutyl ketone (MIBK) diluent demonstrated a more favorable affinity of Am 3+ than Eu 3+ at high acidity levels. Slope analysis showed the formation of 1:2 metal/ligand extracted species. The extraction was a spontaneous exothermic process. The analyses of fluorescence titration, Fourier transform infrared (FT-IR), Raman, time-resolved laser fluorescence spectrum (TRLFS), electrospray ionization mass spectrometry (ESI-MS), conductivity and microcalorimetric titration revealed that the composition of complex is [Eu(NO 3 ) 2 (H 2 O)∙2(Et- p -Tol-A-PzPy)](NO 3 ). Combining the results of solvent extraction and complexation study, the extraction mechanism was proposed. Furthermore, the stability constants (log β ) and thermodynamic parameters (Δ H , Δ S , Δ G ) for complexation of Eu 3+ with Et- p -Tol-A-PzPy were also presented.
研究领域:
化学
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核化学
·
环境科学
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高影响因子
JOURNAL OF RARE EARTHS
·
2018
·Vol. 36
·期 8
·873-878
·
IF 2.524
Yongchao Fang,Xiufang Cui,Zhaobing Cai,Chang Wang,Guo Jin
One of the problems limiting the application of Stellite 6 coating is the residual stress resulting in cracks in the coating easily. In order to reduce the residual stress and increase the nano-indentation hardness, La 2 O 3 was added to Stellite 6 coating in this study, and the influence on the microstructure, nano indentation hardness and residual stress of the coatings were investigated by scanning electron microscopy (SEM) with energy dispersive spectrum (EDS), X-ray diffraction (XRD) and nano-indentation tester. Results indicate that the addition of La 2 O 3 leads to the phenomenon that the dendrite is partly transformed into the equiaxed grain, which results in the grain refinement. The nano-indentation hardness of coatings is improved, which is attributed to the fine-grain strengthening and dispersion strengthening effect of La 2 O 3 . With the addition of La 2 O 3 , the residual stress in coatings is decreased significantly. Especially, when the content of La 2 O 3 is 0.8 wt%, the nano indentation hardness increases by 1.31 times and residual stress decreases to 20 percent, compared with coating without La 2 O 3 .
研究领域:
材料科学
·
表面工程
·
金属学与金属工艺
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力学性能
·
显微组织分析
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高影响因子
Polymers
·
2023
·Vol. 15
·期 8
·1887
·
IF 5
Hui Fang,Guifeng Li,Kai Wang,Fangjuan Wu
This study investigates the effect of adding stearic acid (SA) on the thermal conductivity of polyamide 6 (PA6)/boron nitride (BN) composites. The composites were prepared by melt blending, and the mass ratio of PA6 to BN was fixed at 50:50. The results show that when the SA content is less than 5 phr, some SA is distributed at the interface between BN sheets and PA6, which improves the interface adhesion of the two phases. This improves the force transfer from the matrix to BN sheets, promoting the exfoliation and dispersion of BN sheets. However, when the SA content was greater than 5 phr, SA tends to aggregate and form separate domains rather than being dispersed at the interface between PA6 and BN. Additionally, the well-dispersed BN sheets act as a heterogeneous nucleation agent, significantly improving the crystallinity of the PA6 matrix. The combination of good interface adhesion, excellent orientation, and high crystallinity of the matrix leads to efficient phonon propagation, resulting in a significant improvement in the thermal conductivity of the composite. The highest thermal conductivity of the composite is achieved when the SA content is 5 phr, which is 3.59 W m−1K−1. The utilization of a composite material consisting of 5phr SA as the thermal interface material displays the highest thermal conductivity, and the composite also demonstrates satisfactory mechanical properties. This study proposes a promising strategy for the preparation of composites with high thermal conductivity.Keywords:thermal conductivity;polyamide;boron nitride;stearic acid
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高影响因子
JOURNAL OF THE INDIAN CHEMICAL SOCIETY
·
2023
·
IF 1.3
Yanmin Shen,Yu Bi,Peixia Zhao,Xiaolong Yang,Zheng Zhang,Dan Dang,Han Wang,Wenju Liu
Investigation upon the solid–liquid equilibrium on solubility data of 6-propyl-2-thiouracil (PLT) in pure organic solvents is essential for separation and purifying in industry process. In this work, PLT solubility in nine neat solvents was experimentally determined at 278.15 K–323.15 K under P = 0.1 MPa. These selected solvents were tetrahydrofuran(THF), acetone, acetonitrile,1-butanol,1-pentanol, 2-butanol, methyl acetate, ethyl acetate,1-propyl acetate, respectively. Experiment results showed that solubility was consistent with temperature and decreased according to the order: THF > acetone>1-butanol≈1-pentanol> 2-butanol > methyl acetate > ethyl acetate>1-propyl acetate > acetonitrile. Solvent effect and Hansen solubility parameter (HSP) were incited to explain dissolution rule on solute. Four thermodynamic models (modified Apelblat model, Van't model, λh model and NRTL model) were adopted to correlate PLT solubility and provide good correlations on basis of RD, ARD and RMSD. In addition, thermodynamic properties (Δ H °, Δ S ° and Δ G °) of PLT dissolution process in pure solvents were discussed and proved to be endothermic, entropically driven and non-spontaneous process.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 140
·期 6
·e53457
·
IF 3.057
Bowen Li,Guojun Song,Zhi Peng,Wenjian Zhang,Hao Zheng,Junjie Zhu,Chaohang Wang,Jianfa Wang,Ruiyue Ma,Shaoqian Zhu,Xiaoping Yang,Yudong Huang,Lichun Ma
Carbon fiber (CF) reinforced matrix composites have been applied widely, however, the interfacial adhesion of composites is weak due to smooth and chemically inert of CF surface. To solve this problem, A polydopamine/nano-silica (PDA-SiO 2 ) interfacial layer on carbon fiber surface was constructed via polydopamine and nano- SiO 2 (CF-PDA-SiO 2 ) by a facile and effective method to reinforce polyamide 6 composites (CFs/PA6). The effects of PDA-SiO 2 interfacial layer on crystallization structure and behavior, thermal properties, and mechanical properties of CFs/PA6 composites were investigated. Furthermore, interfacial reinforcement mechanism of composites has been discussed. This interfacial layer greatly increased the number of active groups of CF surface and its wettability obviously. The tensile strength of CF-PDA-SiO 2 /PA6 composites increased by 28.09%, 19.37%, and 26.22% compared to untreated-CF/PA6, CF-PDA/PA6, and CF-SiO 2 /PA6 composites, respectively, which might be caused by the increased interfacial adhesion between CF and PA6 matrix. The thermal stability, crystallization temperature, crystallinity, and glass transition temperature (T g ) of CF-PDA-SiO 2 /PA6 composites improved correspondingly, attributing to the heterogeneous nucleation of nano-SiO 2 in the crystalline area and hydrogen bonds with molecular chains of PA6 in the amorphous area. This work provides a novel strategy for the construction of interfaces suitable for advanced CF composites with different structures.
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高影响因子
RENEWABLE ENERGY
·
2023
·
IF 8.7
Qiaofei Zhang,Wenlei Xie,Jiangbo Li,Lihong Guo
For the purpose of fabricating an efficient solid acid catalyst for biodiesel production from low-grade acidic oils, bimetallic silica mesoporous composites with different Zr/Al molar ratios were initially synthesized via a facile one-step hydrothermal method , and then sulfated with sulfuric acid at different concentrations to get a series of sulfated Zr x -Al y -KIT-6 catalysts (denoted as SZA-K, where x/y represents the molar ratio of Zr to Al). The sulfated bimetallic solid catalysts were fully characterized by using XRD , FT-IR, TEM, SEM, EDS, NH 3 -TPD, and nitrogen porosimetry measurements. Results showed that the remarkable amount of acidic sites in the catalysts was derived from the Zr and Al incorporation and further sulfation, and specifically, the Zr 4+ and Al 3+ could afford abundant weak acid sites while the inductive effect of SO 4 2− species greatly influences the acidic strength of this solid catalyst. In combination with the enhancement in mass transfer resulting from the inherent interconnected mesoporous structure, the SZA-K catalyst could facilitate the transesterification reaction to take place efficiently. The sulfated Zr 5 –Al 1 -KIT-6 catalyst (Zr/Al molar ratio of 5/1, treated using 0.75 mol/L sulfuric acid for 12 h) exhibited enhanced acid strength with larger number of acidic sites (7.81 mmol/g), resulting in a high catalytic performance to the oil transesterification reaction. An oil conversion of 96.3% was attained for the transesterification reaction performed at 120 °C for 7 h by using a methanol/oil molar ratio of 20:1 and a catalyst dosage of 6 wt%. Further, this solid catalyst exhibited better acid and water-resistance capacity with above 80% of oil conversion even with 10% of free fatty acid (FFA) and 2% of moisture present in the low-grade acidic oils. Meanwhile, the good reusability was shown for this catalyst with 80.1% conversion even after reusing for three cycles. The good stability of the solid catalyst was resulted from the strong interactions between the acidic species and the bimetallic composite support.
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高影响因子
POLYMER DEGRADATION AND STABILITY
·
2023
·
IF 5.9
Yanlu Sun,Zhengqi Wang,Dequn Wu,Xueli Wang,Jianyong Yu,Ruchao Yuan,Faxue Li
The absence of inherently flame-retardant polyamide 6 (FR-PA6) with enhanced anti-dripping and melt spinnability has significantly limited its further application in textiles. In this work, a binary reactive flame retardant composed of commercial 9,10-dihydro-10-[2,3- di ( hydroxycarbonyl ) propyl ]-10-phosphaphenanthrene-10-oxide (DDP) and synthesized polydiphenylsiloxane (PDPS) was employed to fabricate FR-PA6 through a facile synthetic route. The prepared FR-PA6 containing 5 wt% DDP and 5 wt% PDPS (FR-PA6-5-5) exhibited a UL94 V-0 rating with no melt-droplets during combustion, a 31.0% reduction in heat release rate and a 18.8% decrease in total heat release compared to pure PA6 in cone calorimetric tests. The improved fire safety of FR-PA6-5-5 was contributed to the gas-phase quenching and dilution effect and the condensed-phase barrier effect, which was enhanced by the synergistic charring effect achieved through the formation of P(= O )-O-Si. Additionally, FR-PA6-5-5 exhibited excellent melt spinnability as demonstrated by the successful preparation of filaments with a tensile strength of approximately 2.27 cN/dtex.
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高影响因子
MICROCHIMICA ACTA
·
2023
·Vol. 190
·期 8
·1-8
·
IF 5.7
Li Dawei,Ren Yaofei,Chen Ruoyang,Wu Haoyu,Zhuang Shaoyong,Zhang Ming
A spiral interdigitated MXene–assisted field effect transistor (SiMFETs) was proposed for determination of IL-6 in patients with kidney transplantation infection. Our SiMFETs demonstrated enhanced IL-6 detection range of 10 fg/mL–100 ng/mL due to the combination of optimized transistor’s structure and semiconducting nanocomposites. Specifically, on one hand, MXene-based field effect transistor drastically amplified the amperometric signal for determination of IL-6; on the other hand, the multiple spiral structure of interdigitated drain-source architecture improved the transconductance of FET biosensor. The developed SiMFETs biosensor demonstrated satisfactory stability for 2 months, and favorable reproducibility and selectivity against other biochemical interferences. The SiMFETs biosensor exhibited acceptable correlation coefficient ( R 2 =0.955) in quantification of clinical biosamples. The sensor successfully distinguished the infected patients from the health control with enhanced AUC of 0.939 (sensitivity of 91.7%, specificity of 86.7%). Those merits introduced here may pave an alternative strategy for transistor-based biosensor in point-of-care clinic applications. Graphical Abstract
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高影响因子
ACS Omega
·
2022
·
IF 4.132
Jinglei Cui,Dan Ren,Jingjing Tan,Huirong Zhang,Yanxia Guo,Long Huang
Toluene is one of the typical volatile organic compounds in industry, particularly in energy and fuels production processes, which is required to be eliminated effectively to protect the environment. Catalytic oxidation of toluene is widely studied for its high efficiency, and rational design and synthesis of metal catalysts are keys for toluene oxidation. In this study, an efficient catalyst was designed and synthesized by introducing −NH2 groups on the ordered mesoporous silica (KIT-6) surface to anchor and disperse Pd species, leading to Pd nanoparticles being highly dispersed with uniform particle size distribution. Meanwhile, it was found that the introduction of −NH2 made Pd centers present an electron-rich state, and the active Pd centers could activate O2 molecules to generate more reactive oxygen species and promote the conversion of toluene, which was verified by in situ XPS and O2-TPD characterization. Compared with the catalysts prepared by an impregnation method, the catalytic performance of the Pd/NH2-KIT-6 (0.5 wt %) catalyst was significantly improved. A conversion of 90% for toluene (2400 ppm, 24,000 mL·g–1·h–1) was achieved at 171 °C, and the toluene conversion was maintained above 90% for 900 min, displaying the excellent activity and stability of the Pd/NH2-KIT-6 catalyst.
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PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Na Sun,Bo Zhu,Xun Cai,Liyuan Yu,Xiaomin Yuan,Ye Zhang
Commercial carbon fiber (CF) sizing agent is generally characterized by poor temperature resistance and incompatibility with polyamide resin, which adversely affects the interfacial properties of CF/polyamide composites. In this paper, we utilize the feature that anionic ring-opening polymerization of caprolactam (CPL) can synthesize polyamide 6 (PA6) in situ, introduce CPL precursor on the CF surface, and initiate polymerization to generate PA6 coating to modify CF. By changing the concentration of precursor solution, the amount of PA6 on the CF surface was effectively regulated, and the modified CF coated completely and uniformly can be obtained. The results show that PCF-20 (CF treated with 20 wt% precursor solution) reinforced polyamide composites have the best interfacial properties. Compared with the desized CF/PA6 composites, the interfacial shear strength (IFSS) and interlaminar shear strength (ILSS) of PCF-20/PA6 composites increased by 49.92% and 31.94%, respectively. The interface image illustrated that the high interfacial wettability of PA6 coating on CF surface results in mechanical mesh between fiber and resin, which is the main reason for the enhancement of composite interfacial properties. Therefore, the in-situ synthesis of PA6 coating to modify CF is an effective method to improve the interface properties of CF/polyamide composites.
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