JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2018
·Vol. 85
·期 3
·506-513
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IF 1.745
Fei Zhifang,Yang Zichun,Chen Guobing,Li Kunfeng
Abstract Polyimide cross-linked silica aerogels with different weight percentages of polyimide were prepared through sol–gel technology and supercritical CO 2 fluid drying technology. Tetraethoxysilane (TEOS) was used as a silica source precursor, 3-aminopropyltriethoxysilane (APTES) end-capped polyimide was used as a cross-linking agent, derived from 3, 3′, 4, 4′-biphenyltetracarboxylic dianhydride (BPDA) and 4, 4′-oxydianiline (ODA). The acid produced during the imidization process catalyzed the hydrolysis reaction without additional catalyst. After condensation reaction catalyzed by ammonium hydroxide solution, the polyimide cross-linked silica gels were obtained and then dried in supercritical CO 2 . The polyimide cross-linked silica aerogels have low density (0.132~0.187 g/cm 3 ), high specific surface area (623–741 m 2 /g), low thermal conductivity (0.0306~0.0347 W/m K at room temperature), relatively high compressive strength (1.03~3.82 MPa) and high thermal decomposition temperature (360 °C). This research provided a simple and efficient method that used the polyimide as a strengthening phase to improve the mechanical properties of TEOS-based silica aerogels.
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JOURNAL OF MOLECULAR STRUCTURE
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2020
·
IF 2.463
Meiyu Xu,Guangming Liang,Shuang Wang,Xueli Ma,Guangyuan Liang,Qingling Ni
The semi-rigid polycarboxylic acid, 4′,4′,4′-[(trimethylamino)]-tris[(1,1′-biphenyl)-2-car- boxylic acid] (H 3 TMCA), is first synthesized and used to self-assembly three cadmium coordination polymers , formulated as {[Cd(HTMCA)]•(H 2 O)•(DMA)} n (1), {[Cd(HTMCA)(H 2 O)]·(H 2 O) 5 } n (2), {[Cd(TMCA)] - (CH 3 CH 3 NH 2 ) + •H 2 O} n (3) by the reaction of Cd(NO 3 ) 2 ·4H 2 O under solvothermal conditions. The coordination polymers have been characterized by elemental analysis , IR spectroscopy , thermogravimetric analysis and single-crystal X-ray diffraction. Complex 1 is a 2D framework with a point symbol of {6˄3}. Complex 2 exhibit a 3D topology net with point symbol of {10˄3}. Complex 3 display a (3,6)-connected 3D topology net with point symbol of {4.6 2 } 2 {4 2 .6 10 .8 3 }. The structural comparison of complexes 1–3 shows that the final frameworks can be adjusted by changes in the reaction of temperature and solvents. Moreover, the solid-state photoluminescence properties of 1 – 3 have also been investigated.
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Microorganisms
·
2026
·Vol. 14
·期 2
·322
·
IF 4.2
Yifan Chen,Li Zhang,Yan Chen,Wenpei Ge,Hongling Wang,Zhanying Xue,Xinran Cui,Xin Wang,Aimei Liao,Yuansen Hu,Na Liu
Fusarium solani , a widely distributed plant pathogenic fungus, poses a significant threat to various crops due to its complex pathogenic mechanisms and being difficult to control. In this study, LC–TOF–MS analysis identified 4-(4-hydroxyphenyl)-2-butanone (RK) as a metabolite detected in Bacillus amyloliquefaciens strain M1, and a commercially available RK standard was subsequently used to evaluate its antifungal activity against F. solani . Antifungal assays demonstrated that RK effectively suppressed fungal growth. Further physiological and biochemical assays confirmed that RK disrupts the cell membrane and mitochondrial function, leading to intracellular reactive oxygen species (ROS) accumulation. This study offers new perspectives on the antifungal mechanism of RK and offers theoretical support for the development of innovative agricultural disease management strategies.
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PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2016
·Vol. 51
·期 16
·7585-7597
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IF 2.302
Zhong Hanyi,Qiu Zhengsong,Tang Zhichuan,Zhang Xin,Xu Jiangen,Huang Weian
In order to develop high-performance water-based drilling fluid with the aim of meeting the increasing requirement of drilling industry, highly inhibitive and high-temperature-resistant shale inhibitors are essential. In this study, 4, 4′-methylenebis-cyclohexanamine was introduced as a potential shale inhibitor. The inhibitive properties of the amine compound in comparison with currently available polyether diamine inhibitor were evaluated using bentonite inhibition test, shale cuttings hot-rolling dispersion test, linear swelling test, and pressure transmission test. The inhibitive mechanism was investigated with zeta potential measurement, X-ray diffraction analysis, and contact angle measurement. The results indicated that 4, 4′-methylenebis-cyclohexanamine can inhibit shale hydration and dispersion effectively, and prevent pressure transmission to a certain extent, performing better than that of polyether diamine. Furthermore, the new diamine provides reliable thermal stability as high as 220 °C, preserving the benefits of high-temperature wells application. This novel diamine inhibits shale hydration and dispersion with the combination of chemical inhibition and physical plugging. The intercalation into the interlayer of clay with monolayer collapses the hydrated clay structure and expels the water molecules. After adsorption, clay surface became more hydrophobic, which prevents the imbibition of water. The variation of solubility separates the compound from the solution, which can plug the micro-pores of shale and prevent fluid invasion.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2012
·Vol. 128
·期 3
·2020-2029
·
IF 1.289
Sujuan Pang,Nai Xu,Guang Xu,Lisha Pan,Qiang Lin,Xin Wang
Poly(propylene carbonate) (PPC) is inferior in thermal stability and liable to incur thermal degradation, especially in the existence of residual bimetal catalyst. In this article, PPC containing residual catalyst was end-capped with 4, 4′-diphenylmethane diisocyanate (MDI) through melt compounding. The blends were characterized by infrared spectra, melt flow index (MFI), gel permeation chromatography (GPC), gel content measurement, thermogravimetric analysis, scanning electron microscopy, and tensile test. The effect of MDI on thermal stability, molecular weight, and tensile properties of PPC was studied. Thermal degradation kinetics of neat PPC and PPC+MDI blending samples was discussed with Friedman method. MFI, GPC, and gel content measurements showed that mainly end-capping reaction was carried out on PPC chains when 0.1% of MDI was added. However, as the amount of MDI exceeded to 0.3%, end-capping, chain-extension, and crosslinking reactions were synchronously carried out on PPC. Results showed that the end-capping, chain-extension, and crosslinking reaction occurring between PPC and MDI could effectively inhibit the unzipping degradation even when the residual catalyst was not removed thoroughly. When the content of MDI reached 1.0%, the initial degradation temperatures ( T - 5% ) increased from 176.26°C for neat PPC to 259.56°C. As a result, the processing temperature range and processing time were largely extended, and the heat resistance of PPC was improved remarkably. Meanwhile, the tensile property of the modified PPC was enhanced obviously. It may be due to the fact that the molecular weight and gel content of PPC were increased with the increasing amount of MDI. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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高影响因子
Crystals
·
2020
·Vol. 10
·期 3
·173
·
IF 2.404
Panpan Zhang,Ke Zhang,Shuliang Dou,Jiupeng Zhao,Xiangqiao Yan,Yao Li
Several kinds of polyimide (PI) films stemmed out of 4, 4’–diaminodiphenyl ether, as well as various structurally various aromatic dianhydride, were prepared. The films’ mechanical, dielectric, and dynamic mechanical attributes were put under investigation. According the findings, the PI films’ performance is significantly different as a result of their diverse structure. PI’s dielectric constant and dielectric loss tangent of abides by the increasing order below: PMDA-PI>BTDA-PI>BPDA-PI. Moreover, the electric breakdown strength of BTDA-PI (478.90 kV/mm) presents a lot higher value compared to the one PMDA-PI (326.80 kV/mm) and BPDA-PI (357.07 kV/mm). In particular, BTDA-PI film possesses high electric breakdown strength about 478.90 kV/mm. In addition, PI’s glass transition temperature (Tg) are, respectively, 276 °C (BTDA-PI), and 290 °C (BPDA-PI), as well as 302 °C (PMDA-PI). Therefore, in virtue of their various structures and performances, practical applications of PI films can exert significant role in the electronics and microelectronics industries.Keywords:polyimide;film;dielectric properties;thermal properties
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高影响因子
HIGH PERFORMANCE POLYMERS
·
2021
·
IF 2.161
Kai Ma,Hanzhou Jiang,Guofei Chen,Wei Wang,Yonggang Zhang
Several polyimides were prepared via two-step polycondensation from novel 2,5-furandicarboxylic acid–based diamine, 2,5-bis[4-(4-aminophenoxy)benzoyl]furan, with commercial dianhydrides. The chemical structures of the monomers and polymers were characterized by FT-IR and NMR in detail, respectively. The polyimides exhibited high performances with 5 wt% weight loss temperatures of over 410 oC, glass transition temperatures of over 214 oC, and tensile strengths and Young’s moduli of up to 130 MPa and 3.2 GPa, respectively. The thermal crosslinking mechanism was studied by FT-IR, Raman spectroscopy, and model reaction analysis, which showed the Diels–Alder reaction between the furan group and diphenylethylene group was the main reaction. The crosslinked polyimide films showed improved solvent resistance, and thermal and mechanical properties.
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高影响因子
Polymer Chemistry
·
2020
·Vol. 11
·期 37
·5992-5997
·
IF 5.342
Haipeng Lu,Xiang Wang,Xianjing Zhou,Wei Zhang,Xinping Wang
Over the past few decades, global paper consumption has continued to increase. The growing demand for paper has aggravated the negative impact on the environment. Therefore, the development of an erasable ink or rewritable paper seems to be an ideal way to alleviate this crisis. In this work, a hydrophilic anthracene derivative with nucleophilic substitution at position 9 was designed and synthesized. Such an anthracene derivative could disperse in aqueous solution and dimerize fast under irradiation of UV or visible light, accompanied by fluorescence quenching. Its aqueous solution could be used as a novel ink to be written on conventional paper, of which the handwriting was only visible under ultraviolet light. When exposed to sunlight, the handwriting would gradually disappear and not reappear after irradiating with ultraviolet light or heating. Therefore, it can be used as an erasable ink for applications in data confidentiality or paper reuse.
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高影响因子
AUSTRALIAN JOURNAL OF CHEMISTRY
·
2019
·Vol. 72
·期 7
·533-541
·
IF 1.226
Sai Huang,Mei Yang,Xin-Yu Deng,Qian Jiang Zhu,Ying Huang,Zhu Tao,Kai Chen
In the present work, a host–guest system of a hemimethyl-substituted cucurbit[6]uril derived from 3α-methyl-glycoluril (HMeQ[6]) and a hemicyanine dye, trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (t-DSMI) showing strong fluorescence emission has been evaluated as a fluorescent probe. The results of a preliminary systematic study on the detection of a series of inorganic anions have revealed that this Q[n]-based host–guest fluorescent probe shows clear responses to BF4− and H2PO4− anions through distinct fluorescence quenching. Application of this Q[n]-based host–guest interaction system in anion recognition or detection opens a new avenue in Q[n] chemistry.
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高影响因子
ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Kang Ma,Qian Tang,Chun-rong Zhu,Jun-fei Long,Cheng-bin Gong,Xiang-kai Fu
This work reports novel dual-colored and fast switching electrochromic materials based on pyridinium salts , 1,1′,1″,1‴-tetrakis(4,4′,4″,4‴-tetrapyridyl)cyclobutane derivatives (TPCBDs). TPCBDs show outstanding electrochromic properties including fast electrochromic switching, dual color, reasonable contrast, low driving voltage, and good stability. TPCBDs are promising candidates for visible electrochromic displays because of their remarkable electrochromic behaviors.
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高影响因子
PROGRESS IN ORGANIC COATINGS
·
2018
·
IF 2.955
Weinan Gong,Xiaoshuang Yin,Ying Liu,Yun Chen,Wenzhong Yang
The inhibitory effects of 2-amino-4-(4-methoxyphenyl)-thiazole (MPT) on mild steel corrosion were evaluated in 0.5 M H 2 SO 4 and 1 M HCl solutions, respectively. From the analysis of potentiodynamic polarization curves and electrochemical impedance spectroscopy, MPT can effectively inhibit the corrosion of mild steel in acidic solutions. Under the optimal conditions, the inhibition efficiency ( η ) was as high as 95% in 0.5 M H 2 SO 4 solution. The inhibition property of MPT was much better than that of the reported corrosion inhibitor 2-amino-4-phenylthiazole (APT). Polarization curves also demonstrated that MPT mainly inhibited the anodic corrosion of mild steel in HCl solution and the cathodic corrosion in H 2 SO 4 solution, respectively. The adsorption of MPT on the surface of mild steel was found to obey Langmuir adsorption isotherm in both acid solutions. Quantum calculations suggest that the addition of electron donor group (−OCH 3 ) endowed the molecule better adsorption ability on mild steel surface. The interaction between protonated MPT and anions on Fe (0 0 1) surface was firstly investigated using molecular dynamic stimulations, and the results showed that with the adsorption of sulfate ions, MPTH + had a superior binding energy on the surface of Fe. The investigation of UV–vis spectrum demonstrated the direct correlation of the experimental data and the theoretical calculations.
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高影响因子
BIOLOGY AND FERTILITY OF SOILS
·
2018
·Vol. 54
·期 7
·807-817
·
IF 3.808
Xiang Leilei,Song Yang,Bian Yongrong,Liu Guangxia,Herzberger Anna,Gu Chenggang,Jiang Xin,Wang Fang
To test whether manure amendment in soil reduces plant uptake of persistent organic pollutants, carrot ( Daucus carota L. ) was used as a model plant and 2,2′,4,4′-tetrabrominated diphenyl ether (BDE-47) was selected as a model persistent organic pollutant to conduct a pot experiment with contaminated soil amended by composted pig manure. The results showed that the concentration and bioconcentration factors (BCFs) of BDE-47 in the edible part of carrot significantly decreased from 229.7 ± 28.2 to 43.4 ± 20.4 ng g −1 and from 1.86 ± 0.5 to 0.15 ± 0.03, respectively, with increasing composted pig manure dose from 0 to 4%. Organic matter (OM) derived from composted pig manure played a dominant role in reducing persistent organic pollutant bioavailability in soil. Composted pig manure amendment and carrot cultivation jointly altered the bacterial community composition in soil, especially the rhizosphere. Rhizodegradation of BDE-47 was enhanced from 8.6 to 28.5% with increasing composted pig manure dose from 0 to 4%, corresponding to increased soil microbe diversity and polybrominated diphenyl ether-degrading bacteria ( Sphingomonas , etc.) abundance in the rhizosphere. This study is the first, to the best of our knowledge, to provide an effective agronomic strategy of manure amendment to reduce plant uptake and simultaneously enhance rhizodegradation of persistent organic pollutants in soil, and thus potentially reduce human health risks through dietary intake.
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