JOURNAL OF MEMBRANE SCIENCE
·
2014
·
IF 4.908
Guang Lu Han,Pei Yu Xu,Ke Zhou,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
A series of poly (arylene ether sulfone) block copolymers with hydrophilic segments containing fluorene groups were successfully synthesized as confirmed by 1 H NMR. The molecular weights were measured in the range 115–140 kDa by gel permeation chromatography (GPC). The hydrophilic segment showed a helical structure due to fluorene with butterfly-shaped framework in the main chain. With incorporating imidazolium groups, the microphase separation can also be achieved between the hydrophilic and the hydrophobic moieties. The membrane structure was characterized by positron annihilation lifetime spectroscopy (PALS) and small angle X-ray scattering (SAXS). The block copolymers were used to prepare membranes successfully for pervaporation separation of methanol (MeOH)/methyl tert-butyl ether (MTBE) mixture. The correlation between the membrane microstructure and the separation performance was discussed thoroughly. By increasing the hydrophilic segment proportion, the permeation flux increased while the separation factor declined. The membranes have the highest permeation flux (0.334 kg m −2 h −1 ) and the lowest separation factor (287) for a 15 wt% MeOH feed mixture at 40 °C, and the mass fraction of MeOH in the permeate is higher than 98 wt%.
✓ 已验证
产品关联
DOI
高影响因子
Analytical Methods
·
2013
·Vol. 5
·期 19
·5037-5043
·
IF 1.855
Yingtang Li,Yang Jiao,Yuhong Guo,Yaling Yang
A new and fast microextraction technique termed vortex-assisted supramolecular solvent microextraction (VASUSME) has been developed. The method was based on the microextraction of endocrine disrupting compounds (EDCs), including bisphenol-A (BPA), 2,4-dichlorophenol (2,4-DCP), bisphenol-AF (BPAF) and tetrabromobisphenol-A (TBBPA) in 10 mL sample with 500 μL of a supramolecular solvent (SUPRASs), and then detection by high-performance liquid chromatography (HPLC). In the VASUSME procedure, dispersion of microvolumes of a low density extraction solvent into the aqueous sample is achieved by vortex mixing, a mild emulsification procedure. Under the optimum conditions, the repeatability of the proposed method was found to be good. The relative standard deviations (RSD, n = 5) were 3.98–5.64%. The limits of detection (LOD) were in the range of 0.14–0.32 ng mL−1 and the limits of quantification (LOQ) were in the range of 0.41–1.02 ng mL−1. All correlation coefficients of the calibration curves were higher than 0.998. Recoveries of the EDCs spiked into samples of liquid foods and their packaging materials were in the range of 91% to 105.1%. The VASSUSME method was successfully applied to the analysis of BPA, 2,4-DCP, BPAF and TBBPA in samples of liquid foods and their packaging materials. Moreover, the method is simple, sensitive and environmentally-friendly and consumes much less solvent than traditional methods.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2013
·Vol. 130
·期 4
·2801-2808
·
IF 1.395
Miao Yin,Li Yang,Xiu-yun Li,Han-bing Ma
The fluorinated epoxy resin, 2,2-bisphenol hexafluoropropane diglycidyl ether (DGEBHF) was synthesized through a two-step procedure, and the chemical structure was confirmed by 1 H n uclear magnetic resonance (NMR), 13 C NMR, and Fourier transform infrared (FTIR) spectra. Moreover, DGEBHF was thermally cured with methyl hexahydrophthalic anhydride (MHHPA). The results clearly indicated that the cured DGEBHF/MHHPA exhibited higher glass transition temperature ( T g 147°C) and thermal decomposition temperature at 5% weight loss ( T 5 372°C) than those ( T g 131.2°C; T 5 362°C) of diglycidyl ether of bisphenol A (DGEBA)/MHHPA. In addition, the incorporation of bis-trifluoromethyl groups led to enhanced dielectric properties with lower dielectric constant ( D k 2.93) of DGEBHF/MHHPA compared with cured DGEBA resins ( D k 3.25). The cured fluorinated epoxy resin also gave lower water absorption measured in two methods relative to its nonfluorinated counterparts. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2801–2808, 2013
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 9
·7239-7248
·
IF 3.289
Lizi Huang,Mingyan Liao,Xin Yang,Hao Gong,Liang Ma,Yudan Zhao,Kun Huang
Bisphenols (BPs) are a group of chemicals with two hydroxyphenyl functionalities. BPs analogues including bisphenol A (BPA), bisphenol B (BPB), bisphenol F (BPF), bisphenol S (BPS), bisphenol AF (BPAF), bisphenol AP (BPAP), tetrabromobisphenol A (TBBPA) and tetrachlorobisphenol A (TCBPA) are widely used in the production of plastic materials. There has been a growing concern worldwide about environmental BPs exposure due to their potential adverse effects on human health. Deposition of β-cell toxic misfolded human islet amyloid polypeptide (hIAPP), a hormone biosynthesized and secreted by the pancreatic β-cells, is a cardinal finding in type 2 diabetes mellitus (T2DM). Epidemiological studies suggest BPA exposure is positively associated with the incidence of T2DM, which may be due to the exacerbated toxic aggregation of hIAPP induced by BPA as we previously reported. Here, we demonstrate that bisphenol analogues showed different effects on hIAPP amyloid formation. Unlike the accelerating effects of BPA, four BPs analogues (BPAF, BPAP, TBBPA and TCBPA) showed inhibitory effects on hIAPP aggregation and decreased the membrane disruption capacity of hIAPP. Our results also explained a possible relationship between the spatial structure and the inhibitory capacities of BPs analogues.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2017
·
IF 6.035
Dong Guo,Chen Xiao Lin,En Ning Hu,Lin Shi,Faizal Soyekwo,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
Clustered alkyl side chains bearing a string of three imidazolium cations with hexyl spacers are grafted to fluorene-based poly (arylene ether sulfone) successfully. Nanostructure is directly configured within the anion exchange membranes (AEMs) via the novel multi-cation side chains. As confirmed by atomic force microscopy (AFM) and small angle X-ray scattering (SAXS), percolating OH – conducting channels with the size of ionic clusters nearly 20 nm endow the trimPES-0.4 membrane with an excellent ion conductivity in excess of 120 mS cm –1 at 80 °C. Because of the self-assembly of ionic groups, water molecules are compartmentalized into the hydrophilic side chain regions instead of backbones, resulting in advantageous over water management. Together with the lengthened hydrophobic segments, TrimPES-0.2 exhibits superior dimensional stability (12.0%, 30 °C) to conventional mono-cation type AEMs. Furthermore, the novel multi-cation TrimPES-0.4 displays a peak power density of 134.4 mW cm –2 at a current density of 280 mA cm –2 . Therefore, these findings suggest that by tuning the distribution of cations, AEMs with well-balanced performance can be made for fuel cell applications .
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2017
·
IF 6.395
Chen Xiao Lin,Xiu Qin Wang,Ling Li,Fang Hua Liu,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
To explore highly conductive and alkaline stable anion exchange membrane (AEM) materials, triblock copolymers bearing alkyl-tethered cycloaliphatic quaternary ammonium-head-groups are prepared via nucleophilic substitution , Friedel-Crafts acylation, ketone reduction and Menshutkin reaction . The designed triblock copolymers composed of quaternized poly(phenylene oxide) segments and poly(ether sulfone) segments are responsible for the microphase separated morphology and well-connected ion domains, as confirmed by transmission electron microscopy . The highest conductivity, up to 105.1 mS cm −1 at 80 °C is achieved for the AEM with ionic exchange capacity (IEC) of 1.81 meq g −1 . Furthermore, the AEMs show robust alkaline stability due to the alkyl-tethered cation-head-groups structure. High retention of hydroxide conductivity (88.9%) and IEC (91.2%) is observed for the AEMs via degradation test in a 1 M aqueous KOH solution at 80 °C for 480 h. Based on the AEM with high conductivity, a H 2 /O 2 fuel cell achieves a peak power density of 176.5 mW cm −2 (80 °C) at a current density of 500 mA cm −2 .
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2016
·
IF 3.299
Wenjing Ma,Zhongfu Guo,Juntao Zhao,Qian Yu,Fang Wang,Jingquan Han,Hui Pan,Jianfeng Yao,Qilu Zhang,Sangram Keshari Samal,Stefaan C. De Smedt,Chaobo Huang
In recent years, efficient, cost effective oil-water separation technologies are highly desired due to frequent oil spill accidents. To design fibrous membranes for efficient oil-water separation, ‘flexible’ polyamide acid (PAA), being polyamide acid with ether linkages in the backbone, and ‘heavily’ fluorinated polybenzoxazine (F-PB) were synthesized. Cellulose acetate (CA) and PAA were co-axially electrospun; the PAA core was then imidizated at high temperature to obtain core/shell structured CA/polyimide (PI) electrospun fibrous membranes; subsequently the surface of the fibers was modified with F-PB, in the presence or in absence of silica nanoparticles (SNPs). The mechanical strength, surface wettability, chemical and thermal stability, and oil-water separation potential of thus obtained PI/CA fibrous membranes were evaluated. The membranes show a much higher critical tensile stress (130 MPa) and critical tensile strain (52%), when compared with CA fibrous membranes. Due to the use of the ‘heavily’ fluorinated polybenzoxazine, the membranes are superhydrophobic with a water contact angle of 162° and an oil contact angle which approaches 0°. Interestingly, the newly designed PI/CA/F-PB-1/SNP-4 membranes can effectively separate various oil-water mixtures, solely driven by gravity, with a high flux (3106.2 ± 100 L m −2 h −1 ) and a high separation efficiency (>99%) and thus possess great potential for oil–water separation.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2016
·
IF 5.557
Chen Xiao Lin,Yi Zhi Zhuo,Ao Nan Lai,Qiu Gen Zhang,Ai Mei Zhu,Mei Ling Ye,Qing Lin Liu
A series of novel side-chain-type anion exchange membranes (AEMs) composed of poly (arylene ether sulfone)s backbone and pendent imidazolium-functionalized polyphenylene oxide (PPO) was prepared via chemical grafting, bromination, functionalization and alkalization. The chemical structure of the as-synthesized copolymers was confirmed by 1 H NMR spectroscopy . Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the morphology of the AEMs. The densely functionalized side chains are found to be beneficial to the formation of ion clusters, as demonstrated by TEM. As a result, the hydroxide conductivity of the PAES-x-IMPPO membranes was 78.8 mS cm −1 at 80 °C. Moreover, the AEMs also exhibit robust mechanical properties , good thermal stability and reasonable alkaline stability. An open circuit voltage (0.98 V) of H 2 /O 2 alkaline fuel cell using PAES-15-IMPPO at 60 °C can be an indicative of low fuel crossover. The maximum power density was 56.8 mW cm 2 at a current density of 125 mA cm 2 without optimization.
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2016
·
IF 0
Xiaobo Wang,Lihua Zhu,Libin Wan,Heqing Tang
Graphene was used to remove low-level environmental endocrines in micro-polluted water with the aid of an investigation about the adsorption of bisphenols at low levels in a very wide range from 0.0005 to 70 mg L −1 . It was found that over the wide concentration range, the adsorption isotherms could be divided into two regions: they followed the Freundlich model in the lower concentration region (correlation coefficient R 2 > 0.99), but obeyed the Langmuir model in the higher concentration region (R 2 > 0.99). This was attributed to the adsorption-induced changes in the morphology of graphene, which created different adsorption sites on the surface of graphene. The obtained values of thermodynamic parameters Δ G 0 , Δ H 0 and Δ S 0 indicated that the adsorption was a spontaneous, exothermic and entropy-decreasing process. The absolute values of these parameters tended to be decreased with increasing bisphenol concentration, suggesting stronger affinity of the binding sites on graphene for the adsorption of the bisphenols at lower concentrations. As confirmed by some characterization and monitoring experiments, the increased bisphenol adsorption decreased the surface grooved regions formed by wrinkles and increased the flat regions. The highly and lowly-wrinkled (or flat) surface states of graphene accounted for the observed two-stage adsorption isotherms.
✓ 已验证
产品关联
DOI
HIGH PERFORMANCE POLYMERS
·
2016
·
IF 1.045
Bei Liu,Zheng Chen,Liming Lin,Yuntao Han,Jinhui Pang,Zhenhua Jiang
3,6-Diphenyl-9H-carbazole pendants are grafted herein to poly(arylene ether ketone)s (PAEKs) via the Ullmann C–N coupling reaction. To the best of our knowledge, this is the first time that PAEKs containing a carbazole pendant (Cz) have been synthesized through the Ullmann C–N coupling reaction. The high molecular weights of PAEK-Cz (PAEKs with 3,6-diphenyl-9H-carbazole pendants) are inherited from their precursors, owing to the high reactivity of their monomers. The obtained PAEK-Cz-x polymers exhibit good solubility in most common organic solvents and excellent thermal stabilities, with the 5% weight loss temperatures for all products being above 598°C under a nitrogen atmosphere. The glass transition temperatures are all above 199°C and can be controlled by adjusting the feed ratio of monomers. The polymer membranes obtained by the casting method are tough and thus have strong potential for practical applications.
✓ 已验证
产品关联
DOI
高影响因子
Materials Chemistry Frontiers
·
2017
·Vol. 1
·期 10
·2031-2038
·
IF 0
Zhenzhen Cai,Yuping Zhang,Yilong Song,Qiuli Cheng,Yang Zheng,Zhanchen Cui,Zuosen Shi,Changming Chen,Daming Zhang
In this paper, we report the design, synthesis, and optical properties of novel negative-type fluorinated polycarbonate photoresists (FPC-PRs) and their use in thermo-optic switches. The novel polymer films are readily fabricated by spin coating on a silicon wafer followed by irradiation with UV light and post-baking at 110 °C. These films exhibit low roughness, good thermal stability (Td, up to 292 °C), high transparency (up to 97.8% at 400 nm) and high refractive indices (RI, 1.583–1.512 at 1550 nm). Channel optical waveguide and MZI thermo-optic waveguide switch arrays were fabricated based on the direct UV-written technique using the FPC-PR 2. The propagation loss of the channel waveguide was only 0.17 dB cm−1 at 1550 nm. The rise and fall times of the device with an applied 500 Hz square-wave voltage were 837 μs and 381.8 μs, respectively. The applied electric power as the switching power was about 35 mW, and the extinction ratio was measured to be about 14.0 dB.
✓ 已验证
产品关联
DOI
POLYMER
·
2017
·
IF 3.684
Yunji Xie,Bei Liu,Zheng Chen,Xiaocui Han,Baijun Liu,Haibo Zhang,Jinhui Pang,Zhenhua Jiang
A series of poly(arylene ether ketone)s (PAEKs) with dense sulfonic-acid-functionalized pendants were successfully synthesized by the Ullmann C–N coupling of a polymer precursor containing pendant iodobenzene rings and 3,6-ditrityl-9H-carbazole, followed by sulfonation using chlorosulfonic acid. A tough transparent membrane, which exhibited suitable dimensional stability and high proton conductivity, was obtained by casting an N , N -dimethylacetamide polymer solution . DSPAEK-CZ-25 (IEC = 2.03 meq. g −1 , where IEC = ion-exchange capacity) exhibited the highest proton conductivity of 177 mS cm −1 at 100 °C; this value is significantly greater than that of Nafion 117. In terms of molecular design, the large difference in polarity between the fluorinated polymer backbone and the concentrated pendant sulfonic acid groups possibly induces good phase-separation morphology, which enhances conductivity and dimensional stability. The obtained membranes exhibited excellent thermal stabilities and good mechanical properties . Overall, the DSPAEK-CZ polymers exhibited outstanding comprehensive performance as potential materials for proton exchange membranes (PEMs).
✓ 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）