JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·Vol. 140
·期 39
·e54455
·
IF 3
Wenjie Feng,Jiadeng Zhu,Chen Yang,Wentao Li,Mengjin Jiang
Poly-p-phenylene-(1,3,4-oxadiazole) (POD) fibers have attracted tremendous attention due to the excellent thermal stability, however, their poor ultraviolet (UV) resistance seriously restricted the application. Some efforts have been devoted to improving the UV stability of POD, while the methods are generally too complicated or costly. This work applied a simple but effective approach to obtain POD/PPTA composite fibers by blending poly-p-phenylene terephthamide (PPTA) with POD. The results showed that the obtained POD/PPTA composite fibers exhibited enhanced tensile strength and heat resistance compared to the pure POD fibers. The POD/10%PPTA composite fibers retained 68% strength and 43% elongation even after 24 h UV accelerated aging. The improvement of UV resistance was attributed to the photoinduced electron transfer reaction in POD/PPTA composite fibers, which has been demonstrated by both experimental and simulation studies.
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ADVANCED ENGINEERING MATERIALS
·
2021
·Vol. 24
·期 4
·2101044
·
IF 3.862
Shibo Wang,Penghao Sun,Xu Xu,He Liu,Dan Wang,Xujuan Huang
Environmentally friendly flame retardant such as polysiloxane has long been sought for varied studies in recent years and can be further improved to overcome the challenges of additional applications. Herein, a novel synergistic-effect flame retardant containing Si and P is synthesized. Si-P containing flame retardant (DOPO-MGSO) is then added into a network to fabricate rigid polyurethane foam via a one-step process. The bio-renewable resource maleopimaric acid (MPA) impedes conversion of the cyclic siloxane, thereby enhancing the compactness of the silica layer in condensed phase. Furthermore, the DOPO groups quench free radicals in the gas phase. Compared with the unmodified sample, the limiting oxygen index of the modified foam increases from 17.1% to 25.2%. Moreover, CONE tests show that the peak heat release rate decreases from 260.1 to 136.2 kW m −1 (close to 50%) after modification. Importantly, the generation of silica-rich char significantly reduces the total smoke release (decrease from 1154.4 to 715.9 m 2 m −2 ). In addition, the improvement of compressive strength benefits from the MPA rigid ring.
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Molecular Catalysis
·
2023
·
IF 4.6
Bowen Wu,Yixi Chen,Mingtai Liu,Yi Tang,Gengfeng Zheng,Linping Qian
The surface properties of CoMg/Al 2 O 3 were evaluated in the aerobic oxidation of p -cresol. The surface interaction is enhanced greatly after Co and Mg impregnation with the mole ratio of Co/Mg from 2 : 1 and 2 : 3. The strongest interaction for the nonpolarity and benzene ring was found on CoMg/Al 2 O 3 with Co/Mg of 2 : 3. But for the interaction with p -π group bonding with negative anion, the highest value appears on the catalyst with the Co/Mg of 2 : 2. In aerobic oxidation of p -cresol, the conversion is significantly increased with Co addition and reaches around 60 % after 24 h' reaction at 338 K. The highest selectivity of p -hydroxybenzaldehyde of 99 % is achieved on Al 2 O 3 with the co-impregnation mole ratio of Co/Mg of 2 : 2. It is suggested that medium adsorption of the reactants and strong stabilization of the intermediates facilitate the aerobic oxidation of p -cresol to p -hydroxybenzaldehyde.
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OPTICS EXPRESS
·
2023
·Vol. 32
·期 1
·366-378
·
IF 3.8
Feida Li,Kangning Liu,Jun Dai
Flexible perovskite solar cells (F-PSCs) prevail in the clean energy field for their light weight, easy fabrication and installation, but the power conversion efficiency of F-PSCs needs further improvement. In this work, we numerically simulate and experimentally demonstrate the effect of the perovskite trap defects density on the power conversion efficiency. The pseudo-halide KBF4 is employed as the additive to passivate the trap defects in the perovskite films. The high electrophilicity of BF4- group ensures its entering into perovskite lattice, optimizing crystallinity and improving the qualities of perovskite films, K+ ions can effectively passivate grain boundaries and inhibit halide anion migrations. After KBF4 passivation, trap defect density of the perovskite film was decreased from 8.0 × 1015cm−3 to 3.9 × 1015cm−3, and also the carrier lifetime increased from 108.52 ns to 234.72 ns. Consequently, the power conversion efficiency (PCE) of the F-PSCs devices increased from 13.99% to 16.04%.
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PubMed
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2023
·Vol. 49
·期 12
·5361-5374
·
IF 3.3
Du Chuanqing,Huang Yeyin,Tang Wanjun,Sun Lang,You Qingliang,Li Tingcheng,Xie Guangyong
Formulation and shaping of heterogeneous catalysts are vital in the successful industrial application. Here micro-sized vanadium chromium composite oxides catalysts with the spherical shape were prepared via spray drying with colloidal silica as a binder material. The physicochemical properties of catalysts with different Cr/V molar ratios were characterized by XRD, XPS, FT-IR, TPR, and particle size distribution analysis. It was revealed that the addition of Cr inhibited the formation of the crystalline phase V 2 O 5 and decreased the reduction temperature of pentavalent vanadium species, and also resulted in the formation of monoclinic CrVO 4 and a highly dispersed state of vanadia species. VCrO/SiO 2 particles with various Cr/V atomic ratio were studied as catalysts for p -chlorotoluene ammoxidation to p -chlorobenzonitrile, in which the catalyst with Cr/V ratio of 1 exhibited the best catalytic performance. When the Cr/V ratio was less than 1, mixed phases of orthorhombic CrVO 4 and monoclinic Cr 2 V 4 O 13 were formed and resulted in a low catalytic activity. With the increase of Cr/V ratio, the content of monoclinic CrVO 4 in the catalysts increased, resulting in the catalytic activity of the catalysts improved. However, too large an amount of Cr led to the formation of highly oxidizing hexagonal-Cr 2 O 3 phase, which reduced the selectivity of the catalytic reaction. Graphic abstract
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Energies
·
2023
·Vol. 16
·期 21
·7232
·
IF 3.2
Congxiu Guo,Guilin Li,Yujia Wu,Xuhui Wang,Yu Niu,Jiao Wu
Porous carbon materials derived from ZIF-8 have attracted extensive research attention on account of their large surface area, tunable mesoporosity and abundant nitrogen content. However, directly carbonized ZIF-8 usually suffers from a low electronic conductivity, poor wettability and relatively low mesoporosity, which severely restricts their capacitive performance. Herein, P-doped modified carbon materials derived from ZIF-8 (ZPCs) were synthesized by using nontoxic phytic acid as a phosphorus source, followed by carbonization at high temperature. Benefiting from its relatively high specific surface area of 911.7 m2g−1and higher ratio of mesopores, as well as N, O and P doping, ZPC-1000 delivers the largest specific capacity, up to 219.4 F g−1at 1 A g−1, among the prepared samples and an outstanding cycle span, retaining 100% capacity after 2000 cycles at 5 A g−1. In this work, we highlight the strategy of constructing a synergistic effect between high mesoporosity and heteroatom doping, which can greatly boost the capacitive performance of carbon materials.Keywords:P doping;ZIF-8;porous carbon;capacitive performance
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EUROPEAN POLYMER JOURNAL
·
2023
·
IF 6
Wanyu Zhang,Weiping Chen,Jiamin Lv,Ying Wu,Xinwu Ba,Liping Fang
Multi-responsive hydrogels for temperature sensor and information encryption were developed through the synergistic application of light, temperature and pH response of the hydrogel. The multi-responsive hydrogels were prepared by copolymerization of dimethylaminoethyl methacrylate (DMAEMA) and 7-(2-methacryloyloxyethoxy)-4-methylcoumarin (CoumMAc). Through incorporating coumarin groups into the hydrogels, the crosslinking degree of hydrogels could be increased by photo-crosslinking of polymer chains based on the photodimerization of coumarin groups. After the hydrogel was irradiated by a photomask under UV light (365 nm), the irradiated and unirradiated region in the hydrogel showed different crosslinking degrees, leading to different volume phase transition temperature (VPTT) in the two region of the hydrogel. The pattern in the hydrogel appeared only within a specific temperature range, and the temperature of the environment can be monitored by the prepared hydrogel sensor. After soaking the patterned hydrogel in the acidic solution, no pattern information was displayed at all temperatures, and the pattern information can only emerge by dual decryption (base and temperature). In addition, the information can be erased by UV light (254 nm), which further ensures information security. This work provide a new way for low-cost unpowered temperature sensors and information encryption with more security.
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FUEL
·
2021
·
IF 6.609
Ruru Zhou,Yuanyuan Jiang,Huaiyuan Zhao,Boyong Ye,Lina Wang,Zhaoyin Hou
Acetalization of glycerol with acetone could convert surplus glycerol into an important fuel additive (solketal). In this work, a stable solid acid catalyst was synthesized in a facile polycondensation of p -phenolsulfonic acid on KH560 modified SiO 2 (PSF/K-SiO 2 ) and used in the acetalization of glycerol at room temperature. Characterization results confirmed that PSF/K-SiO 2 possessed larger surface area and surface acidity than that of PSF resin (copolymer of p -phenolsulfonic acid and formaldehyde) and non-modified SiO 2 supported PSF resin (PSF/SiO 2 ). As a result, PSF/K-SiO 2 was extremely active and stable in the acetalization of glycerol. At 25 °C, the detected conversion of glycerol reached 86.3% with a 97.7% selectivity of solketal at 1.5 h. The best yield of solketal over PSF/K-SiO 2 could reach 93.1 g-solketal/g-cat/h, and PSF/K-SiO 2 could be recycled at least 5 times without obvious decrease in reactivity.
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PROGRESS IN ORGANIC COATINGS
·
2021
·
IF 5.161
Jie Zhang,Xiang Zhang,Yuying Zheng
Graphene (G) is an excellent protection material, but suffering corrosion-promotion effect because of its intrinsic high electrical-conductivity. Herein, a facile strategy is presented to effectively lower the conductivity of the G by the encapsulation of insulating poly(p-phenylenediamine) (PpPD). The obtained G@PpPD, which delivers an extremely low conductivity of 3.5×10 −7 S cm -1 , were then mixed with polyvinyl-butyral (PVB), forming a compact composite coating that can effectively protect Q235 steel from being corroded over a very long period. Such a superior anticorrosion property can be owing to the synergistic effect between impermeable graphene and insulated PpPD, which not only hinders the diffusion of the corrosive media, but also inhibits the corrosion-promotion activity of the graphene. This effective strategy may provide valuable enlightenment for the further development of graphene-based polymer anticorrosive coatings with long-lasting corrosion resistance .
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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
·
2020
·
IF 4.947
Xiu Li,Yimin Xuan,Qiang Li
Conventional microchannels provide effective chip cooling with constant flow rate and this comes at the cost of high pumping power consumption. Considering the dynamic heat load in reality, a self-adaptive microchannel cooling is desired for regulating the flow rate to diminish the operational cost while preserving the inherent cooling effectiveness. Taking the advantages of easy synthesis, well tunable lower critical solution temperature (LCST) and remarkable mechanical strength, this paper reports the self-adaptive microchannel cooling with the thermal-sensitive nanocomposite (NC) P(MEO 2 MA- co -OEGMA) hydrogel. A novel route is developed to integrate the hydrogel with the chip using template-aided imprint molding and in situ polymerization. Circular hydrogel is elaborately designed and anchored firmly in the channel. The cooling performance is tested with a custom test vehicle under different operating conditions. The hydrogel acts as a smart valve and tailors the flow rate from 0.14 mL/s to 0.46 mL/s based on heat load variation. Compared with conventional channels, heat flux of 100 W/cm 2 can be extracted with similar temperature rise while the coefficient of performance (COP) is improved by an order of magnitude. The transient characteristics and repeatability are also validated. The self-adaptive scheme offers both effective and economical liquid cooling for modern electronic devices.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2020
·
IF 7.1
Dongxue Sun,Tianli Liu,Yuming Dong,Qingyun Liu,Xiuming Wu,Guang-Li Wang
Herein, an innovative dehydrogenase invoked tri-enzyme cascade has been successfully constructed and utilized as a powerful and universal colorimetric strategy for dehydrogenase-based bioassays. Specifically, the glucose-6-phosphatedehydrogenase (G6PD) catalyzes the specific dehydrogenation of glucose-6-phosphate (G-6-P) by consuming the oxidized form of β-nicotinamide adenine dinucleotide phosphate (NADP + ) to generate NADPH. And the formed NADPH initiates the irreversible hydroxylation of p-hydroxybenzoate by p-hydroxybenzoate hydroxylase (PHBH) to generate 3,4-dihydroxybenzoate (DHB), which results in the subsequent in situ generation of a photoresponsive nanozyme of DHB coordinated SrTiO 3 (SrTiO 3 /DHB) nanosheets. The photoresponsive nanozyme has intriguing interfacial charge transfer (ICT) characteristics and thus realizes the efficiently catalytic oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) under light irradiation for signal readout. Exemplified by G6PD and G-6-P as analytes, the dehydrogenase invoked tri-enzyme cascade achieved efficient signal amplification towards the ultrasensitive colorimetric bioassays. This study opens up the ICT transitions of SrTiO 3 for innovative dehydrogenases-involved enzyme cascades. In addition, it is an entirely new method for dehydrogenases-based bioassays, with the distinctive merits of facile operation, rapid response, high sensitivity, and naked-eye readout. Importantly, it is extensible as a general basis for other numerous targets of interest because of the large numbers of dehydrogenases available for catalysing different reactions.
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Linjuan Wang,Siva Krishna Karuturi,Ling Zan
We present one-pot hydrothemal syntheis of SnS 2 -In 2 S 3 p-n heterostructures for photocatalytic reduction of Cr 6+ to Cr 3+ . The conduction bands of In 2 S 3 and SnS 2 serve as the photogenerated electron donors and acceptors, respectively, forming a p-n junction band alignment improving the photogenerated charge separation efficiency. Through a detailed investigation of photocurrent spectra, photoluminescence spectra and electrochemical impedance, the heterojunction formation is shown to enhance the photogenerated charge separation and transport properties. In addition, the analysis of 5,5-Dimethyl-1-pyrroline N-oxide (DMPO) spin trapping electron spin resonance (ESR) spectra and band structure further testify the p-n junction of the composite catalyst that could accelerate the electron transport and change the pathway of photocatalytic process toward Cr 6+ reduction. Furthermore, SnS 2 -In 2 S 3 heterojunction photocatalyst achieved 3 times and 67 times higher efficiency than pure In 2 S 3 and SnS 2 photocatalysts under visible light toward Cr 6+ reduction. Moreover, the SnS 2 -In 2 S 3 p-n heterojunction photocatalyst demonstrates Cr 6+ removal in a weak alkaline solution, breaking through the challenge of Cr 6+ reduction in an alkaline environment.
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