Polymer Chemistry
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2012
·Vol. 3
·期 12
·3330-3339
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IF 5.321
Cheng-guang Mu,Xiao-dong Fan,Wei Tian,Yang Bai,Zhen Yang,Wei-wei Fan,Heng Chen
We describe the synthesis and self-assembly of a well-defined H-shaped terpolymer in this paper. A block copolymer of poly(ethylene glycol) (PEG) and poly(N,N-dimethylaminoethyl methacrylate) (PDMA), which bears an azido group at the diblock junction (PEG–N3(–PDMA)) was first prepared by atom transfer radical polymerization. Then, an alkynyl-terminated narrow distributed polytetrahydrofuran (PTHF-Alk) was synthesized as another building block via cationic ring opening polymerization. The well-defined H-shaped terpolymer was afforded by clicking PEG–N3(–PDMA) onto both chain-ends of PTHF-Alk. This H-shaped terpolymer can self-assemble into micelles with different sizes and morphologies at various solution pH values. The micellar size also exhibits temperature-dependence at pH 7.4 and 9.2. The variation of size and morphology of the micelles with the solution pH and temperature is ascribed to the pH- and thermo-responsive properties of the PDMA block.
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CONSTRUCTION AND BUILDING MATERIALS
·
2017
·
IF 3.169
Jinfeng Sun,Hu Shi,Binbin Qian,Zhiqiang Xu,Weifeng Li,Xiaodong Shen
This work investigates the influence of synthetic C-S-H/polycarboxylate(PCE) nanocomposites (CPNs) on the hydration and properties of hydrated cement pastes. HPEG-PCE copolymers exhibiting side chain length of 45 ethylene oxide (EO) units was utilized to synthesize CPNs by precipitating C-S-H from Na 2 SiO 3 and Ca(NO 3 ) 2 in the PCE solution. A Box-Behnken Design (BBD) for the Response Surface Methodology (RSM) was employed to statistically optimize the sizes of the resultant. The prepared CPNs were characterized by particle size distribution (PSD), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR) and thermo gravimetric/derivative thermo gravimetric (TG/DTG) analyses. The influence of CPNs on the hydration properties of cement were assessed and discussed in terms of hydration kinetics, mechanical properties, phase composition and pore structure analysis. The experimental results showed that the optimum synthetic parameters, an experimental temperature of 30.1 °C, reactant flow velocity of 0.63 ml/min and initial volume of PCE solution of 28.5 ml, produced CPNs with a minimum size of 329.12 nm. It was demonstrated that PCE polymers were either grafted on the surface or partially intercalated in the interlayer regions of C-S-H, and their introduction also increased the distance between C-S-H interlayers. Cement hydration was significantly promoted as a result of an increased heat release, even at low CPNs content. The early compressive strength of the mortar significantly improved with increasing CPNs content due to the accelerated cement hydration of the CPNs: the 0.6 wt.% CPNs content improved the compressive strength by 18.97%. Moreover, the inclusion of CPNs is advantageous for pore modification: the total porosity decreased by 25.77% after 3 days. Finally, phase composition analysis confirmed that no new crystalline phase was produced upon CPNs addition.
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ACS Applied Polymer Materials
·
2024
·
IF 4.4
Hao-Jia Guo,Xiaodong Qiao,Ben-Xiang Hu,Shuangquan Liao,Ming-Chao Luo
The recycling of waste rubber (WR) is beneficial to the sustainable development of rubber industries. However, interactions among WR are weak, limiting the recycling of WR. In this work, our group designed bis-diazo compounds to promote interactions among WR for recycling through aliphatic C–H insertion strategies. Specifically, upon hot pressing, bis-diazo compounds produce bis-carbenes which react with C–H on the surface of WR by C–H insertions, and then we obtain recycled WR materials. As a result, stress–strain curves show that the strength of recycled WR increases steadily with the increase of bis-diazo compound loading, which has reached the level of butadiene styrene rubbers. Moreover, the introduced disulfide bonds endow recycled WR with reprocessability. Stress–relaxation experiments at different temperatures show that recycled WR with disulfide bonds have unique vitrimer viscoelastic properties. The feasibility of bis-diazo compounds to enhance interactions among WR through C–H insertions opens opportunities to recycle and reinvent industrial WR.
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JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
·
2024
·
IF 3.1
Guanru Chen,Fengjian Chu,Shuheng Zhang,Wangyu Li,Shiwen Zhou,Wei Wei,Weiwei Chen,Xiaozhi Wang,Lei Yue,Hongru Feng,Yanli Cui,Yuanjiang Pan
C–H bond ortho-substitution reaction has always been a significant and challenging topic in organic chemistry. We proposed a synthesis method based on microwave plasma torches. High-resolution mass spectrometry was used to monitor rapid reaction products. 2-Alkylbenzimidazole can be formed through the reaction of phenylnitrenium ion and nitriles on a millisecond scale. This reaction can achieve the one-step formation of benzimidazoles from benzene ring single-substituted compounds without the addition of external oxidants or catalysts. A similar C–H bond activation reaction can be accomplished with ketones. Meanwhile, the microwave plasma reactor was modified, and the resulting 2-methylbenzimidazole was successfully collected, indicating the device has good application potential in organic reactions such as C–H bond activation reaction.
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STAR Protocols
·
2024
·
IF 1.3
Wenbin Zhang,Felix Ofori Boakye,Guanwu Lian,Dingyi Zhang,Zhousheng Mo,Henan Chen,Baiyao Liang,Yun Zhang,Wei Zhao
Summary Recently, there has been a growing interest in using sustainable energy to decrease lignin monomers to generate high-value-added products. Here, we present a protocol for electrocatalytic hydrogenation of 5-hydroxymethylfurfural. We describe steps for catalyst preparation, performing electrocatalytic experiments, high-performance liquid chromatography analysis, and in situ infrared reflection-absorption spectroscopy testing. The synthesized catalyst used in this reaction exhibits enhanced selectivity and Faradaic efficiency in NaClO 4 solution. For complete details on the use and execution of this protocol, please refer to Zhang et al. 1
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ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Zhengmei Wu,Chenchen Cai,Xiangjiang Meng,Yanhua Liu,Tao Liu,Zhenxia Zhao
Triboelectric nanogenerators (TENGs) enable self-powered real-time monitoring of pipeline vibration states in chemical engineering systems, providing an effective approach for intelligent operation and maintenance of critical chemical equipment. Metal-organic frameworks (MOFs) can effectively enhance the output performance of TENGs. MOFs can go beyond the original characteristics of their powder form and be customized into different shapes to adapt to the intended applications. However, MOF-based triboelectric materials are typically limited by their poor mechanical properties and high sensitivity to humidity. In this study, the H-bond/ion coordination strategy is employed to immobilize Zeolitic imidazolate framework-8 (ZIF-8) onto delignified wood, successfully designing a cellulose-MOF (CelluMOF) triboelectric material with excellent mechanical properties and superhydrophobic performances. The wood's porous structure induced directional alignment of MOFs along the pore channels, significantly improving mechanical performance. Furthermore, hydrophobic modification is performed on the material surface, achieving a contact angle of 152.6°, demonstrating outstanding humidity stability. The CelluMOF triboelectric material combines the mechanical toughness of wood with the functional properties of MOFs. A self-powered vibration sensor constructed using this material demonstrates exceptional sensitivity, achieving an average identification accuracy of 97.8% in detecting pipeline vibrations. Remarkably, it maintains stable performance even at 85% RH.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
·
IF 24.319
Yalin Yang,Zheyan Chen,Hanlin Huang,Yuxin Liu,Junhua Zou,Shuqi Shen,Jiawei Yan,Jinshui Zhang,Zanyong Zhuang,Zhongzhen Luo,Chengkai Yang,Yan Yu,Zhigang Zou
Halide perovskites and derivatives have been used as emerging photocatalysts due to their unique optoelectronic and structural diversity. However, compared with the well-explored photophysical processes for light-driven more energetic carriers to trigger redox reactions, catalytic effects on the surface of halide perovskite or their derivatives for chemical transformations between reactive species are seldom addressed, which is equally important for improving the efficiency for halide perovskite-based photocatalysts. Here, we demonstrate that Cs 3 Bi 2 Br 9 sites in the Cs 3 Bi 2 Br 9 /CdS heterojunction, not only participate in light-driven processes, but also play a vital role for the activation and conversion of key intermediates during C(sp 3 )-H bond transformation, via a more thermodynamically and kinetically favorable surface reaction pathway. Besides, various aromatic hydrocarbons can be effectively photocatalytic converted to corresponding aldehydes/ketones as major products. This work highlights the importance of surface catalysis mechanism in photocatalysis not only for halide perovskites but also for other semiconductors.
研究领域:
材料科学
·
化学工程
·
光化学
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ACS Sustainable Chemistry & Engineering
·
2026
·Vol. 14
·期 28
·12821-12832
·
IF 7.6
Chen Yuhan,Xie Haiyang,Wu Yubo,Luo Jiangxue,Zhan Tianren,Zhang Yanjuan,Huang Zuqiang,Hu Huayu,Gan Tao
Developing highly efficient Fe-based single-atom catalysts (SACs) for the selective oxidation of C–H bonds to produce value-added aromatic ketones under mild conditions is still challenging. Herein, the construction of amphiphilic Fe SACs with electron-deficient Fe–S 2 O 2 structure supported on porous S-doped lignin-derived carbon (Fe 1 /SLC) was achieved using a ball milling combined with an impregnation method. Due to the synergistic interaction between electron-deficient Fe–S 2 O 2 sites and ethylbenzene (EB)–water microinterfacial effects, Fe 1 /SLC markedly enhanced the catalytic activity and acetophenone (AP) selectivity for the selective oxidation of EB to AP under 60 ° C for 12 h, obtaining an AP selectivity of 99.1% at 99.0% EB conversion and a high turnover frequency (TOF) of 2422.3 mmol EB g Fe –1 h –1 , which were much higher than those of the control catalyts (Fe 1 /LC and Fe NPs /SLC), surpassing most reported catalysts in similar reaction system. The electron-deficient Fe–S 2 O 2 sites were conducive to the cleavage of TBHP to generate 1 O 2 , • O 2 – , and • OH radicals, wherein • O 2 – was dominant, while 1 O 2 and • OH performed a secondary role. Meanwhile, the density functional theory calculations revealed that the amphiphilic property of Fe 1 /SLC induced by the C–SO x –C structure heightened the catalytic activity and AP selectivity, which originated from the unique interfacial hydrogen-bonding interactions and adsorption energy gradients. Furthermore, Fe 1 /SLC showed excellent recyclability, long-term storage stability, and satisfactory universality. This work provides a promising strategy to simultaneously improve the catalytic activity and aromatic ketones selectivity of the selective oxidation of C–H bonds.
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CATALYSIS TODAY
·
2022
·
IF 6.562
Xinyi Xing,Ying Guan,Liping Zhang,Xian Shi,Han Wu,Hui Gao,Siquan Xu
A catalytic system that is both efficient and recyclable is desirable for production 5-hydroxymethylfurfural (HMF) from glucose. In this study, the catalytic system composed of H 2 O (NaCl) -tetrahydrofuran (THF) biphasic system and H-β zeolite was found to have excellent performance for the glucose conversion into HMF. The physicochemical properties of the H-β zeolite catalyst, the dosage of the system components, and the reaction parameters were investigated in detail to optimize the production efficiency of HMF. Under optimal reaction conditions, an advanced level of 84% HMF yield was obtained from glucose. After the reaction was completed, all components of the catalytic system can be recovered, realizing no waste of reagents. Moreover, the recycled H-β(30) zeolite catalyst maintained considerable catalytic stability after five consecutive cycles. Therefore, it is reasonable to believe that the efficient, inexpensive, and recyclable H 2 O (NaCl) -THF catalytic system containing H-β(30) zeolite is capable of showing promising application potential in the future.
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Materials
·
2020
·Vol. 13
·期 10
·2340
·
IF 3.057
Yongzhe Fan,Huazhen Yang,Haisheng Fan,Qi Liu,Chuang Lv,Xue Zhao,Mingxu Yang,Jianjun Wu,Xiaoming Cao
The hexagonal boron nitride (h-BN) nanosheets modified by silane coupling agent (KH560) were doped into acrylic acid coating on the surface of galvanized steel to improve its corrosion resistance. H-BN nanosheets modified by KH560 were prepared and characterised by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The corrosion resistance of the acrylic acid coatings was measured by electrochemical testing. The results show that the corrosion current density of the coating with modified h-BN nanosheets was reduced from 2.2 × 10−5A/cm2to 2.3 × 10−7A/cm2compared with the acrylic acid coating. The impedance of the composite coating with modified h-BN is 4435 Ω·cm2, higher than the BNNS coating (2500 Ω·cm2) and the acrylic acid coating (1500 Ω·cm2). This is due to the physical barrier and electrical insulation properties of the hexagonal boron nitride (h-BN) nanosheets.Keywords:hot-dip galvanized steel;boron nitride nanosheet;corrosion resistance;acrylic coating
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MATERIALS LETTERS
·
2024
·
IF 2.7
Lili Liu,Haomin Bai,Zhi Zhou,Bo Yang,Wentong Liu,Shuai Liang
Owning excellent mechanical properties and mild repair conditions simultaneously has always been a paradox in the field of self-healing polysiloxane elastomer research. In this work, a robust polysiloxane elastomer with autonomic self-repairing at r. t. and recyclable properties was firstly designed and synthesized. The double strong H-bonds ensure the strength of the elastomer, while the urea bond with relatively weak bond energy also acts as a sacrifice bond to dissipate energy and further bolster the mechanical properties. Meanwhile the double dynamic bonds located in the side chain with stronger molecular activity ability help to get good self-healing performance. Additionally, the material that can be recycled by crushing/remolding and dissolving/remolding methods without compromising their mechanical robustness and self-repairing properties is environmentally friendly.
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Polymers
·
2024
·Vol. 16
·期 11
·1491
·
IF 4.7
Hongyi Zhu,Shunxia Wu,Rui Tang,Yang Li,Gang Chen,Bingxue Huang,Biyou Peng
Electronic devices play an increasingly vital role in modern society, and heat accumulation is a major concern during device development, which causes strong market demand for thermal conductivity materials and components. In this paper, a novel thermal conductive material consisting of polydimethylsiloxane (PDMS) and a binary filler system of h-BN platelets and Al2O3nanoparticles was successfully fabricated using direct ink writing (DIW) 3D printing technology. The addictive manufacturing process not only endows the DIW-printed composites with various geometries but also promotes the construction of a 3D structural thermal conductive network through the shearing force during the printing process. Moreover, the integrity of the thermal conductive network can be optimized by filling the gaps between the BN platelets with Al2O3particles. Resultingly, the configuration of the binary fillers is arranged by the shearing force during the DIW process, fabricating the thermal conductive network of oriented fillers. The DIW-printed BN/Al2O3/PDMS with 45 wt% thermal conductive binary filler can reach a thermal conductivity of 0.98 W/(m·K), higher than the 0.62 W/(m·K) of the control sample. In this study, a novel strategy for the thermal conductive performance improvement of composites based on DIW technology is successfully verified, paving a new way for thermal management.
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