MACROMOLECULAR RAPID COMMUNICATIONS
·
2023
·Vol. 44
·期 10
·2200971
·
IF 4.6
Jie Mao,Jing Li,Wang Lin,Faliang Luo
This work describes an easy and effective process for preparing a homogeneous polybutadiene (PB) dielectric elastomer with improved actuated strain by utilizing a photochemical thiol-ene click reaction. The carboxyl groups and various ester groups are used for grafting on the PB. Since the length of the alkyl chains of the ester groups will significantly influence the polarities of the carbonyl groups and hydrogen bonding effect, the influence of polarity and hydrogen bonding effect on the dielectric properties and mechanical properties of the modified polybutadienes is carefully discussed. Very interestingly, it is found that the increment of dielectric constant of PB modified by carboxyl groups is the lowest one compared to other modified PBs with the ester groups. Meanwhile, the modified PBs with the ester groups could achieve pretty low dielectric loss factor, and finally, a high dielectric constant (3.6), low dielectric loss factor (0.0005), and large actuated strain (≈25%) of the modified polybutadienes could be achieved by the modified PBs with butyl acrylate groups. This work provides a simple and effective method for the designing and synthesizing of a homogeneous high electromechanical performance dielectric elastomer with high dielectric constant and low dielectric loss.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Jin Zhang,Suyan Li,Xiaoyu Hu,Lijun Zhang,Yu Chen,Manman Mu,Yadong Bi
It has been a blind spot to compare the modification effect of ester and acid on inorganic photo catalysts. Traditional method is always laborious to realize organic-inorganic combination by the esterification of carboxylic acids with surficial hydroxyls of nano-TiO 2 . Here, a detailed comparison was conducted using m -dipyridyl benzene skeleton (MPB) molecules containing ester or carboxylic acid groups to modify TiO 2 surface with solvothermal method . The result shows that the modification did not affect the crystal structure of TiO 2 , but formed uniformly distributed organic/inorganic binding sites and non-binding sites on its surface, thus the intrinsic UV response activity of TiO 2 can be retained. Combining with the visible light activity of organic/inorganic binding sites, a perfect photogenerated charge transfer system with matching energy levels is constructed, hence the photocatalytic performance is greatly improved. By contrast, the ester derivative of MPB (shorted as EPB) is easier to form stable organic species on the surface of nanoparticles and shows higher catalytic activity than the carboxylic acid derivative of MPB (shorted as APB), thus the study first demonstrated that the low cost and applicable photocatalyst can be obtained with much low dosage of organic modifiers containing ester groups, hence much significant in the design and optimization of catalyst surface. Compared with other reported methods, this modification has the advantages of simple process, low cost, no consumption of precious metals , ease of obtaining high activive and stable catalysts, so it is more prospective in waste water treatment.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING RESEARCH & DESIGN
·
2020
·
IF 3.35
Shaojian Hu,Jianhua Zhu,Bencheng Wu,Rui Ma,Xiaohui Li
As an eco-friendly lubricant base oil, ester base oil is receiving increasing attention. However, studies on synthetic reaction kinetics of high viscosity complex ester have been rarely reported. In this work, based on the principle of equal reactivity of all functional groups and simplified kinetics models, synthetic reaction kinetics for high viscosity complex ester was investigated in two steps. As for the esterification of trimethylolpropane with glutaric acid, the activation energies of the first and second stage were 55.3 and 73.5 kJ/mol, respectively. As for the esterification of the first step products with 2-ethylhexanoic acid, the activation energies of the first and second stage were 60.6 and 98.2 kJ/mol, respectively. As for the esterification of the first step products with n -heptanoic acid, its activation energy was 68.9 kJ/mol. A mutation phenomenon on reaction order from zero to second order was discovered, which could be explained by the strong adsorption of organic acid on catalyst surface. The conversion rate of carboxyl of synthetic reaction for mixed acid ester was estimated by simulation, and average relative error was less than 3.0%. The synthetic process of high viscosity complex ester was considered to consist of a series of parallel–consecutive reactions with addition–elimination mechanism.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
SYNTHETIC METALS
·
2015
·
IF 2.252
Yin Yu,Bo Jin,Rufang Peng,Lisheng Fan,Longhua Cai,Bin Fan,Shijin Chu
A series of [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) analogs with different ester structures, such as isopropyl ester (F 1 ), sec-butyl ester (F 2 ), ethyl ester (F 3 ), 2-thiopheneethyl ester (F 4 ), phenethyl ester (F 5 ), and 4-methoxyphenethyl ester (F 6 ), were designed, synthesized, and evaluated for their photovoltaic performance. The optical, electrochemical, morphological, and photovoltaic properties of the molecules were characterized through UV–vis spectroscopy, cyclic voltammetry, and atomic force microscopy; then, the effects of different ester structures on these properties were investigated. Results showed that polymer solar cells (PSCs) with P3HT as a donor and F 1 –F 6 as acceptors displayed different photovoltaic properties. The PSCs with F 1 , F 2 , and F 3 as acceptors showed higher photovoltaic performance than those with F 4 , F 5 and F 6 as acceptors. Moreover, the power conversion efficiency of the former three PSCs exceeded or approached 3.0%, whereas that of the latter three PSCs was below 2.0%. Compared with PCBM, F 2 and F 3 with an aliphatic ester exhibited a slightly better photovoltaic performance, F 1 with isopropyl ester displayed similar photovoltaic properties, and other aromatic ring ester PCBM-like derivatives showed poorer photovoltaic performance.
研究领域:
材料科学
·
光电化学
✓ 已验证
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2019
·
IF 4.046
Baoguo Ma,Chunbao Li,Yang Lv,Hongbo Tan,Hui Wang,Huahui Qi,Xiaohai Liu,Qi Yang,Pian Chen
The problem of bleeding and segregation in high fluidity concrete can be eliminated by the addition of viscosity-enhancing agents (VEA). However, the dispersion capacity of PCE would be perturbed by the addition of VEA. In most cases, this negative impact was due to competitive adsorption between VEA and PCE. In order to mitigate the negative impact, ester groups were introduced to reduce the adsorption capacity, and one new kind of viscosity-enhancing agents was designed; the polymers were copolymerized of acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA), with 1:1 and 1:8 M ratios of AA and HEA. And then, the effect of these two VEAs on rheology of cement paste plasticized by PCE at 5 min and 30 min were studied. Adsorption behavior was analyzed by total organic carbon (TOC), and the zeta potential was also measured. The conformation of the polymers in liquid phase were analyzed by dynamic light scattering (DLS). And the decomposition of ester group under alkaline condition was verified by FTIR and 1 HNMR. The results indicated that the synthesized VEA could plasticize cement paste, and the reason was that VEA could be adsorbed by cement grains and act as the same role as the first-generation superplasticizer. The plasticizing capacity was increased over time, because the adsorption capacity was enhanced due to the released carboxyl groups from the decomposition of ester groups. Furthermore, from 5 min to 30 min, the decomposition of ester group could increase the conformation size of VEA by producing crosslinking in the presence of Ca 2+ , and the crosslinking act as positive role in increasing viscosity and resist the bleeding and segregation. Moreover, it was observed that VEA had negative impact on dispersion capacity of PCE, and the higher density of ester group resulted in lower negative impact at the beginning; one reason for this was because the higher density of ester group showed lower competitive adsorption capacity. Such results offered one new type of VEA available for superplasticizer system.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 135
·期 10
·45940
·
IF 1.86
Mei Wang,Jianchun Jiang,Jianling Xia,Shouhai Li,Mei Li
Phosphate ester groups containing ricinoleic acid-based Ca/Zn (LPPRA-Ca and LPPRA-Zn) stabilizer was successfully synthesized from ricinoleic acid (RA) and used as thermal stabilizers for poly(vinyl chloride) (PVC). These thermal stabilizers were characterized by Fourier transform infrared spectrometry, 1 H nuclear magnetic resonance, and inductively-coupled plasma atomic emission spectroscopy. The effects of LPPRA-Ca/LPPRA-Zn, CaSt 2 /ZnSt 2 , and other stabilizers on the thermal stability of PVC were studied through Congo Red test, discoloration tests, thermogravimetric analysis (TGA), TGA–infrared, and TGA–mass spectrometry. The thermal stability tests show that LPPRA-Ca/LPPRA-Zn displays the best initial color stability and long-term thermal stability for PVC. The superior performance is attributed to the synergistic effect of LPPRA-Ca and LPPRA-Zn. Moreover, a lower Zinc content of LPPRA-Zn in PVC helps to decrease the “zipper dehydrochlorination” of the product, which contributes to a better initial thermal stability. Except for the better stabilization performance, LPPRA-Ca/LPPRA-Zn also displays better plasticization performance for PVC compared with other stabilizers. A possible stabilizing mechanism of PVC/LPPRA-Ca/LPPRA-Zn system was presented. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45940.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Electronic Materials
·
2024
·
IF 4.3
Yi Zhang,Cheng Peng,Gang Wang,Xinrong Huang,Yingfeng Yu
Fabricating epoxy resins low in both dielectric properties and moisture absorption is of emerging need but challenging, especially in the application of microelectronic packaging materials that are intensively exposed to harsh environments. In this work, a series of diphenols of different substituent positions and groups blocked with ester groups were copolymerized with diglycidyl ether of bisphenol A (DGEBA)-based epoxy resin to synthesize high-molecular-weight hydroxyl-free epoxy thermoplastics (phenoxy resins). Remarkably low dielectric constants down to 2.26 at 1 MHz and low dielectric losses were found in these hydroxyl-free epoxy thermoplastics, which also showed excellent hydrophobicity compared with those of epoxy thermosets and commercialized epoxy thermoplastic. The migration of ester groups in the polymerization process was studied by a series of model reactions, indicating that the reaction mainly undergoes an associative mechanism under catalysis of the imidazole derivative. In addition, the polymers demonstrated good thermal stability, while thermal properties can be easily modulated by changing the substituent group of phenolic ester monomers. In short, these hydroxyl-free epoxy thermoplastics could be a promising candidate for antimoisture microelectronic packing materials and have versatile applications.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2018
·
IF 4.946
Nataliya A. Gavrilenko,Tatyana N. Volgina,Evgeniy V. Pugachev,Mikhail A. Gavrilenko
Polymethylmethacrylate matrix has been developed as an analytical device for visual and spectrophotometric determination of malachite green. Based on the studied effects of different pH levels, temperature, contact time and diverse ions, optimum analysis conditions have been established. For malachite green, the calibration graph was linear in the range of 0.5–30 mg·L −1 in the samples with the detection limit of 1 mg·kg −1 . The proposed simple method makes it possible to determine malachite green visually in the concentration range 8–30 mg·L −1 using a colour scale. The method has been implemented for determination of malachite green in various sea fish samples.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2016
·Vol. 408
·期 19
·5319-5328
·
IF 3.125
Ji Wenhua,Zhang Mingming,Gao Qianshan,Cui Li,Chen Lizong,Wang Xiao
Hydrophilic molecularly imprinted polymers (H-MIP) with molecular recognition ability for iridoid glycosides (IGs) have been obtained via bulk polymerization combined with hydrolysis of ester groups. H-MIP were characterized by Fourier transform infrared spectroscopy (FT-IR). The hydrophilcity was measured by the contact angle measurement and the water dispersion stability. The obtained H-MIP demonstrated high selectivity and specific binding ability to five IGs in aqueous media. The group extraction efficiency of molecular imprinted solid-phase extraction (MISPE) for five IGs was investigated, including loading sample, breakthrough volume, washing solvent, and elution solvent. Compared with non-imprinted solid-phase extraction (NISPE), the higher average recovery (95.5 %) of five IGs with lower relative standard deviations values (below 6.1 %) using MISPE combined with high-performance liquid chromatography (HPLC) were achieved at three spiked levels in three blank samples. Under the optimum MISPE conditions, the wide linear range with the correlation coefficient of R
2 ≥ 0.9950 for five IGs with low limits of detection (LOD) and quantification (LOQ) (0.01–0.08 and 0.03–0.27 μg mL −1 , respectively) were obtained. Chromatograms obtained using MISPE columns demonstrated that the matrix interference has been minimized and great interferences around IGs were also eliminated efficiently. These results indicated that the developed MISPE-HPLC method was selective, accurate, and applicable for the determination of IGs in water media.
Preparation of hydrophilic molecularly imprinted polymers via bulk polymerization combined with hydrolysis of ester groups
研究领域:
分析化学
·
药物分析
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NANOTECHNOLOGY
·
2017
·Vol. 28
·期 28
·285703
·
IF 3.44
Zhuang Hui,Yangai Liu,Wei Guo,Lihang Li,Nan Mu,Chao Jin,Ying Zhu,Peng Peng
Transparent and flexible electrodes on cost effective plastic substrates for wearable electronics have attract great attention recently. Due to the conductivity and flexibility in network form, metal nanowire is regarded as one of the most promising candidates for flexible electrode fabrication. Prior to application, low temperature joining of nanowire processes are required to reduce the resistance of electrodes and simultaneously maintain the dimensionality and uniformity of those nanowires. In the present work, we presented an innovative, robust and cost effective method to minimize the heat effect to plastic substrate and silver nanowires which allows silver nanowire electrodes been directly written on polycarbonate substrate and sintered by different electrolyte solutions at room temperature or near. It has been rigorously demonstrated that the resistance of silver nanowire electrodes has been reduced by 90% after chemical sintering at room temperature due to the joining of silver nanowires at junction areas. After ∼1000 bending cycles, the measured resistance of silver nanowire electrode was stable during both up-bending and down-bending states. The changes of silver nanowires after sintering were characterized using x-ray photoelectron spectroscopy and transmission electron microscopy and a sintering mechanism was proposed and validated. This direct-written silver nanowire electrode with good performance has broad applications in flexible electronics fabrication and packaging.
研究领域:
材料科学
·
纳米技术
·
柔性电子学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
HIGH PERFORMANCE POLYMERS
·
2014
·
IF 1.09
Yongpeng Wang,Haibo Zhang,Mengzhu Liu,Yingshuang Shang,Yingjian Lin,Zhenhua Jiang
A novel poly(arylene ether sulfone) (PAES) with pinacol phenylboronate pendants (PAES-B) was prepared by the borylation of brominated PAES (PAES-Br). The reaction was carried out under mild conditions in the presence of cuprous iodide and tri-n-butylphosphine in tetrahydrofuran solution. After heat treatment at 150°C for 132 h, the PAES-B exhibited an interesting solvent resistance. Fourier transform infrared spectroscopy (FTIR) and thermal analysis were performed to investigate the reason. FTIR spectra showed that heat treatment could facilitate losing of pinacol groups and formation of phenylboronic acid in the polymer. Meanwhile, differential scanning calorimetric (DSC) curves demonstrated that the polymer had cross-linking behaviors during heat treatment. In addition, the thermal oxidative stability of PAES-B was researched by the thermogravimetric analysis (TGA).
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2021
·Vol. 28
·期 10
·1-13
·
IF 3.097
He Jing,Yu Tao,Chen Shaokai,Li Yan
A new thermoset PLA resin was synthesized. The structure and performance of the thermoset PLA resin were characterized by Fourier transform infrared spectroscopy (FTIR), 1 H Nuclear Magnetic Resonance ( 1 H-NMR), 13 C Nuclear Magnetic Resonance ( 13 C-NMR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) testing methods. The results indicate that thermoset PLA resin has been synthesized successfully, and the thermal stability of thermoset PLA is better than that of linear PLA. Thermoset PLA resin and ramie/thermoset poly(lactic acid) (PLA) composites were prepared by casting and hot-pressing, respectively. The degradation behavior was evaluated by surface morphology observation, scanning electron microscope (SEM), pH detection and FTIR analysis. The results show that the thermoset PLA resin fully degrades after 20 days, and the degradation rate of ramie/thermoset PLA composites is only 45.27% after 30 days, which is lower than that of thermoset PLA. The reason is due to that ramie fabric as the barrier hinders the moisture and microorganisms enter the interior of the composites. Moreover, according to the FTIR analysis, the ester groups of thermoset PLA are firstly hydrolyzed, and thermoset PLA is decomposed into low molecular weight oligomers. Then thermoset PLA and oligomers are continuously hydrolyzed by moisture and microorganisms until mineralized into H 2 O and CO 2 . Besides, the soil pH value detection proves that no acidic or alkaline harmful degradation products are produced during the soil degradation process.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）