PROGRESS IN ORGANIC COATINGS
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2019
·
IF 3.42
Panpan Hao,Ting Zhao,Lili Wang,Shaojie Liu,Erjun Tang,Xiaodong Xu
In this paper, a linear isocyanate terminated urethane oligomer, polyethylene glycol modified isophorone diisocyanate oligomer (PEG-IPDI), was prepared by the reaction of polyethylene glycol and isophorone diisocyanate. It is mixed as a cross-linking agent with an acrylic copolymer composed of 2-ethylhexyl acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate and acrylic acid to form a network pressure sensitive adhesive (PSA) through the reaction of isocyanate groups in PEG-IPDI with hydroxyl and carboxyl groups in acrylic copolymer chains. By blending this network PSA with a photo-initiator and a trifunctional acrylic monomer in a certain ratio, the UV-curable PSA was obtained. After uniformly coating it on the treated polyethylene terephthalate film, a UV-induced peelable PSA tape for a silicon wafer dicing process was prepared. The PSA network formed before UV irradiation was held together with another network produced by UV irradiation of the trifunctional acrylate monomer to give an interpenetrating network (IPN) structure. The results showed that this novel UV-curable PSA tape with IPN structure had strong peel strength before UV irradiation, and could meet the fixed requirements of silicon wafer cutting process. After UV curing, the peel strength was remarkably lowered due to the formation of IPN structure. Compared to those semi-IPN structured PSA tapes prepared with traditional multi-functional urethane acrylate oligomers, the adhesion performances of IPN structured UV peelable PSA tape prepared in this work were similar, but the remaining adhesive on the wafer after the release of the UV cured tape was greatly reduced.
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CHEMOSPHERE
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2019
·
IF 5.108
Ying Zhang,Guanting Luo,Qi Wang,Yinqiao Zhang,Minghua Zhou
An UV enhanced electro-Fenton (EF) process was conducted in a flow-through system to remove rhodamine B (RhB) in the presence of ethylenediamine tetraacetate (EDTA). The process was denoted as UV/EDTA/EF where EDTA formed complexes with iron ions, thus keeping them soluble at high pH values. The process was very efficient as it could initiate the fast reduction of Fe III to Fe II and thus the decomposition of H 2 O 2 . The influence of Fe dose, the ratio of EDTA:Fe, aeration rate, flow rate, current, initial RhB concentration and pH on the RhB removal in the UV/EDTA/EF process was investigated. The best RhB removal was obtained as 89.9% at [Fe] 0 = [EDTA] 0 = 0.2 mM, current = 50 mA, aeration rate = 20 mL min −1 , flow rate = 7 mL min −1 , pH = 7 and [Na 2 SO 4 ] 0 = 0.05 M. The degradation of EDTA during the process was also studied. Radical scavenging experiments indicated that OH was the dominant radical for RhB removal. While, the photolysis of Fe III EDTA was mainly responsible for EDTA degradation. RhB and EDTA removal in different systems was compared. The stability test proved that in the presence of EDTA, the UV/EF process could remove RhB with high efficiency in the first two runs. While, the efficiency dropped remarkably after EDTA’s complete depletion. The mechanisms of the UV/EDTA/EF process were proposed. UV/EDTA/EF conducted in the flow-through system was able to efficiently remove RhB as well as EDTA in a wide pH range and proposed as a promising approach for wastewater treatment .
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Scientific Reports
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2019
·Vol. 9
·期 1
·1-14
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IF 4.011
Wang Yizheng,Yu Jiang,Peng Weidong,Tian Jing,Yang Chun
In this paper, we used a facile ball milling, microwave radiation and heating treatment method to achieve the surface modification of TiO 2 with low g-C 3 N 4 concentration, and a multilayer heterojunction composite with TiO 2 as the main part and g-C 3 N 4 as the modification agent was obtained. The obtained materials were analyzed by several characterizations to get information on their chemical composition, crystalline structure, vibrational features and optical properties. The photocatalytic performance was evaluated by degradation of rhodamine B (RhB) and methylene blue (MB) under UV, visible and direct solar light irradiation. Its photocatalytic activity was enhanced depended on the novel structure of g-C 3 N 4 /TiO 2 hybrid and the special Z-scheme electron-hole transfer model of multilayer heterointerfaces. The material preparation and structural features could be useful for the design and development of other photocatalysts with high photocatalytic activity.
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COMPOSITES PART B-ENGINEERING
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2019
·
IF 6.864
Tadele Daniel Mekuria,Chunhong Zhang,Diaa Eldin Fouad
SiC@SiO 2 core-shell nanostructured particles were successfully prepared via simple thermal treatment. The structure of the surfaces of pristine SiC and SiC@SiO 2 core-shell nanostructured particles was investigated by X-ray diffraction spectroscopy (XRD). The formation of SiO 2 shell on the SiC core was further evaluated by FTIR , SEM , XPS and TEM techniques. The nanostructured particles prepared were amino-modified by APTMS and incorporated in polyimide (PI) matrix to prepare highly flexible composite films . The mechanical, thermal, UV-shielding and water proof properties of the composites were investigated. The TGA results displayed that T 5 (5% weight loss temperature) and T 10 (10% weight loss temperature) were meaningfully enhanced up to 56.0 °C and 53.4 °C, respectively upon adding various amounts of modified SiC@SiO 2 nanoparticles into the PI matrix. DSC results revealed that the glass transition temperature ( T g ) was considerably enhanced up to 45.50 °C, up on the incorporation of different dosages of SiC@SiO 2 –NH 2 nanoparticles in the matrix. The tensile results shown that introduction of the nanoparticles into the PI medium exhibited highly significant improvement in the tensile strength and the Young's modulus over 77.1% and 96.6% respectively as compared to the neat PI. The incorporation of SiC@SiO 2 –NH 2 nanostructured particles in the matrix highly improved the hydrophobicity of the composites up to 62.55% as compared to the neat PI. The UV-shielding properties were also enhanced when functionalized SiC@SiO 2 –NH 2 was added to the PI matrix. The dispersion of SiC@SiO 2 in the PI matrix was investigated by Scanning electron microscope (SEM).
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
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IF 4.175
Wei Ma,Lin Li,Ying Liu,Yuyu Sun,Ick Soo Kim,Xuehong Ren
Weak UV light stability of N-halamine-based materials leads to severe antibacterial capacity fading, and further limits their practical applications. Herein, atom transfer radical polymerization (ATRP) method was firstly employed to fabricate ZnO-poly[3-(4-vinylbenzyl)-5,5-dimethylhydantoin] (ZnO-PVBDMH) nanoparticles through a 2-bromoisobutyryl bromide group linked onto the surface of ZnO nanoparticle (ZnO-BIBB). Morphology and structures of ZnO-PVBDMH nanoparticles in relationship to their chemical composition were investigated. Prominent UV light stability results confirmed that ZnO nanoparticles significantly reduce the chlorine loss of N-halamine upon UV irradiation, and about 79% of the active chlorine could be recharged after 72 h of irradiation. The ZnO-PVBDMH-Cl NPs with 1.62 wt% oxidative chlorine could sterilize 99.96% Gram-positive Staphylococcus aureus (3.38 log) and 100% Gram-negative Escherichia coli O157:H7 (7.39 log) within 30 min. After 24 h of UV irradiation, the ZnO-PVBDMH-Cl NPs could still inactivate 97.17% E. coli O157:H7 within 60 min. The nanoparticles also show excellent in vitro cell viability owing to the unique hybrid structures. The excellent photocatalytic capability of ZnO-PVBDMH NPs was investigated by determining the decomposition of the methylene blue (MB) solution. As an easy and efficient way of modifying nanoparticles, such technique can further extend the application of N-halamine monomers in other polar substrates for antibacterial functionalization.
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INDUSTRIAL CROPS AND PRODUCTS
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2019
·
IF 4.191
Bin Liang,Renpu Li,Chaoqun Zhang,Zhuohong Yang,Teng Yuan
A novel tri-functional castor oil-based methacrylate prepolymer (MCOG) was developed by mercapto castor oil (MCO) and glycidyl methacrylate (GMA) in this study through a two-step method. Primarily, the mercapto castor oil (MCO) was prepared through thiol-ene reaction of castor oil and mercaptoacetic acid, and subsequently an esterification reaction based on above product and glycidyl methacrylate (GMA) was conducted. FT-IR and 1 H NMR spectra collectively revealed that MCOG was successfully synthesized. As a dominant component, MCOG was formulated with other additives including a reactive diluent pentaerythritol tri-acrylate (PETA), a photo-initiator (TPO) and another self-made polyurethane acylate prepolymers (B-215) and cured under UV irradiations. UV-curing kinetics of the MCOG/PETA/B-215 film was detailly investigated by tracing the ATR-IR spectroscopy and gel content and it demonstrated that the cured films had more than 95% C C double bond conversion. Moreover, dynamic mechanical property, thermal stability and mechanical property of the cured films were respectively determined by dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA) and tensile measurement. DMA testified that with the increasing of B-215 content, storage modulus, cross-linking density of the cured films dropped, whereas the corresponding glass transition temperatures ( Tg ) increased. TGA showed that the maximum thermal decomposition temperatures were all above 460 °C. Tensile tests indicated that the better tensile strength was obtained with the content of 20% of the B-215 in the cured film. Additionally, transparency and flexibility of the cured films were respectively analyzed by digital image and scanning electron microscopy (SEM). Besides, these cured films displayed high pencil hardness (5H–6H) and excellent resistance to acidic and alkali solutions.
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Analytical Methods
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2019
·Vol. 11
·期 11
·1500-1507
·
IF 2.378
Sha Sha Li,Bo Yin,Hong Lin Zhai,Shao Hua Lu,Jia Ying Mi
Although UV-Vis spectroscopy has been applied in many fields, it still encounters some challenges in multi-component mixture analysis due to severe spectral overlapping and different interferences. In this paper, a Tchebichef curve moment (TM) approach has been developed and proposed for the quantitative analysis of five skin-whitening agents in several cosmetic products with different substrates based on conventional UV-Vis determination for the first time. First, the TMs were calculated from the raw UV-Vis spectra of mixed standard samples, and employed to establish linear quantitative models by stepwise regression. Then, the obtained models were applied to the analysis of real samples. The leave-one-out correlation coefficients (Rloo-cv) of the established models were more than 0.9948 within the linear ranges. The proposed approach was evaluated using intra- and inter-day precision (less than 5.98%) and recovery (ranging from 88.3 ± 2.8% to 109.2 ± 2.3%). The LODs and LOQs were less than 0.13 mg L−1 and 0.45 mg L−1, respectively. Compared with the classical methods, the proposed approach is not only more accurate, reliable and robust in the quality control analysis of cosmetic products, but also can extend effectively the application of conventional UV-Vis determination.
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Journal of Analytical Methods in Chemistry
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2019
·
IF 1.589
Yong Zhang,Xian-Liang Zou,Yong-Li Wang,Lu Gao,Gui-Xin Chou
In this study, we used quantitative high-performance liquid chromatography equipped with an ultraviolet detector (HPLC-UV) and solid phase extraction (SPE) to determine the levels of four phenylethanoid glycosides and five triterpene acids in Liuwei Dihuang capsules (LDCs). LDCs were methanol-extracted and purified using a 500 mg/6 mL silica-based C18 SPE cartridge. Two elutions were analyzed on a ChromCore C18 column under two HPLC conditions. To improve the pretreatment clean-up, an array of silica- and polymer-based SPE cartridges were compared. Both wash and elution steps were also optimized to achieve the highest removal of impurities. Under optimal chromatographic conditions, good linearity was achieved for all compounds (correlation coefficient of r ≥ 0.999), with a quantification limit ranging from 0.0076 to 0.418 μg/mL. The method had satisfactory efficiency and reproducibility with recovery rates ranging from 91.6 to 99.3% with a relative standard deviation below 1.5%. Taken together, this demonstrated SPE as a suitable extension of HPLC-UV for the determination of phenylethanoid glycosides and triterpene acids in complex LDCs.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 1
·1-9
·
IF 6.232
Duo Huixiao,Li Yijing,Liang Xiaojing,Wang Shuai,Wang Licheng,Guo Yong
Magnetic hierarchical nickel/nickel oxide/carbon nanorods (Ni/NiO@C) were prepared via the pyrolysis of a metal-organic framework containing nickel(II) nickel (Ni-MOF; Ni 3 (BTC) 2 ) under argon atmosphere. In this material, magnetic Ni/NiO@C nanoparticles are embedded in porous carbon nanorods, and the morphology is similar to that of the original Ni-MOF precursor. The synthesized nanorods were applied as magnetic sorbents in the solid-phase extraction of five benzoylurea insecticides (flufenoxuron, chlorbenzuron, teflubenzuron, diflubenzuron and triflumuron), and their performance was evaluated under optimized conditions. The results show that the material exhibits high extraction recoveries from spiked samples (82.9%–107.6%) and linear response in the range of 0.2–450 μg·L −1 . It is also characterized by relatively low limits of detection (50–100 ng·mL −1 ) at a signal-to-noise ratio of 3. The sorbent is chemically stable and can be repeatedly recycled, with little decline in extraction capacity after 20 cycles of reuse. The method was successfully applied to the quantification of benzoylureas in tea, wolfberry, millet, and oat samples, and it showed high extraction efficiency.
Schematic representation of the synthesis of magnetic hierarchical nickel/nickel oxide/carbon nanorods derived from Ni-MOF. The material is employed as a sorbent for the magnetic solid-phase extraction of benzoylurea insecticides.
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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2018
·
IF 2.831
Lan Luo,Congcong Gu,Mingxian Li,Xiangyuan Zheng,Feng Zheng
4-Nitrobenzaldehyde is the synthetic raw material and an important photodegradation product of chloramphenicol . With a structural “alert” of human genotoxic potential and reported mutagenicity, this compound should be controlled in drug substances as a potential genotoxic impurity. However, current analysis methods require complex pre-treatment processes and/or lack sufficient specificity and sensitivity. Nitrophenylhydrazine is a common carbonyl derivatization reagent used to determine the residual aromatic aldehydes in drug samples. In the present study, we report an unexpected advantage of 3-nitrophenylhydrazine hydrochloride as a derivatization reagent in the derivatization high-performance liquid chromatography-ultraviolet detection method to determine 4-nitrobenzaldehyde in chloramphenicol samples. Compared with other nitro-substituted phenylhydrazines , 3-nitrophenylhydrazine hydrochloride can minimize drug matrix and derivatization reagent interferences, since the maximum absorption wavelength of its derivative is significantly red-shifted to 397 nm. The derivatization conditions have been optimized in terms of reaction efficiency, including reaction temperature, time, and diluting solvent, through a design of experiments. As a result, after reaction with 500 μg mL −1 of 3-nitrophenylhydrazine hydrochloride in acetonitrile-water (70:30, v/v) at 60 °C for 30 min, the developed HPLC method could be used to determine 4-nitrobenzaldehyde with a limit of detection of 0.009 μg mL −1 . The method was then validated and applied for the determination of residual 4-nitrobenzaldehyde in chloramphenicol and its eye-drop samples.
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COMPOSITES SCIENCE AND TECHNOLOGY
·
2018
·
IF 5.16
Dandan Jin,Shiai Xu
In this study, the effects of polybenzimidazole (PBI) and polyacrylic acid (PAA) modified carbon black (MCB) on the anti-UV-weathering and thermal properties of PVC composites were investigated. The optimal mass ratios of PBI and MCB to PVC are 0.1 wt% and 0.2 wt%, respectively, and the resultant 1PBI/2MCB/PVC composite membrane with a thickness of about 60 μm can block over 99% of UV light below 380 nm. The UV absorption mechanism was investigated by the optional band gap (Eg) and the fluorescence spectroscopy . The incorporation of PBI and MCB results in a decrease in Eg, from 4.96 eV for PVC membrane to 2.90 eV for 1PBI/2MCB/PVC composite membrane, and MCB can quench the fluorescence of PBI by photon-induced electron transfer to further protect PVC. The results of accelerated UV-weathering experiment indicate that the incorporation of PBI and MCB can improve the anti-UV-weathering property of PVC. The thermal degradation behaviors of PVC and its composite membranes in air and N 2 atmosphere were also investigated. The highest char residue (13.7 wt%) is obtained in 1PBI/2MCB/PVC composite membrane at 800 °C in N 2 atmosphere, with an increase of 73.4% compared with that of PVC membrane, which may be because PBI and MCB can synergistically accelerate the carbonization of PVC molecules to rapidly form stable char residue.
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Nanomaterials
·
2019
·Vol. 9
·期 5
·725
·
IF 4.034
Xiangyu Feng,Kai Jiang,Haibo Zeng,Hengwei Lin
Large-scale applications of conventional rare-earth phosphors in white light-emitting diodes (W-LEDs) are restricted by the non-renewable raw material sources and high energy consumption during the production process. Recently, carbon dots (CDs) have been proposed as promising alternatives to rare-earth phosphors and present bright prospects in white lighting. However, the use of CDs in W-LEDs still has two major obstacles, i.e., solid-state quenching and lack of single-component white emissive products. In this work, a facile, rapid, and scalable method for the preparation of solid-state white emissive CDs (W-CDs) is reported via microwave-irradiation heating of L-aspartic acid (AA) in the presence of ammonia. The W-CDs exhibit blue photoluminescence (PL) in dilute aqueous dispersion and their emission spectra gradually broaden (emerging new emissions at orange-yellow regions) with concentration increases. Interestingly, the W-CDs powder displays a very broad PL spectrum covering nearly the whole visible-light region under ultraviolet (UV) excitation, which is responsible for the observed white emission. Further studies revealed that the self-quenching-resistance feature of the W-CDs is probably due to a covering of polymer-like structures on their surface, thus avoiding the close contact of nanoparticles with each other. PL emission of the W-CDs is reasonably ascribed to a cross-linked enhanced effect (CEE) of the sub-fluorophores contained in the material (e.g., –NH2and C=O). Finally, applications of the W-CDs in fabricating single-component-based W-LEDs using commercially available UV chips were attempted and shown to exhibit satisfactory performances including high white light-emitting purity, high color rendering index (CRI), and tunable correlated color temperature (CCT), thus rendering great promise for W-CDs in the field of white lighting.Keywords:carbon dots;photoluminescence;solid state emission;white light-emitting diodes
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危险品化学品经营许可证（带存储）