POLYMER
·
2016
·
IF 3.586
Siqi Huan,Long Bai,Wanli Cheng,Guangping Han
Uniform fibers composed of two concentrations of poly(vinyl alcohol) (PVA) separately reinforced with up to 20 wt% cellulose nanocrystals (CNCs) were successfully produced by electrospinning. The CNCs were well dispersed in both 5 wt% PVA (5PVA) and 7 wt% (7PVA) aqueous solution prior to nanofiber manufacture. Composite nanofibers with controllable ultra-thin diameters of around 200 nm were generated reproducibly at all CNC contents investigated, and the nanofiber diameter turned out to be much smaller at higher CNC content. Interestingly, with the same CNC loading, nanofibrous mats produced from 7PVA reinforced with CNC nanoparticles had higher degree of crystallinity than nanocomposite with 5PVA as the matrix due to the more orderly stack of 7PVA nanofibers as well as the stronger interactions between PVA molecular chains and CNC nanoparticles . High mechanical performance nanocomposite fibrous mats were successfully fabricated by electrospinning an all-aqueous system for their potential application in biological field.
研究领域:
高分子材料
·
纳米复合材料
·
生物医学工程
·
组织工程
·
药物递送
✓ 已验证
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2023
·Vol. 107
·期 2
·490-502
·
IF 2.5
Shen Qiuwan,Cai Zhongwen,Chen Gaokui,Zhang Xin,Li Shian,Yang Guogang
In this study, optimization of the synthesis process parameters of sol-gel method using orthogonal experiment was first applied for CuFe 1.2 Al 0.8 O 4 catalysts in methanol steam reforming (MSR). OA 9 (4 4 ) orthogonal experiments were applied to optimize the synthesis process parameters by sol-gel method, including precursor copper source complexing agent, calcination temperature, and calcination time. The MSR performance was selected as the objective function. Results show that copper source has the greatest impact among the four factors on the catalytic performance. The catalytic performance of the catalyst synthesized by using copper hydroxide as the precursor copper source was much better than the other copper sources. For the other three factors, the order of important factors is: calcination time > complexing agent > calcination temperature. According to the results of range analysis, the optimal synthesis process parameters for CuFe 1.2 Al 0.8 O 4 with best MSR performance are as follows: the precursor copper source is copper hydroxide, the calcination time is 2 h, the complexing agent is ethanol and ethylene glycol, and the calcination temperature is 700 °C. The hydrogen production is 0.077 mol/min/g oat , the methanol conversion rate can reach >95%, and the hydrogen selectivity can reach 99%. CuFe 1.2 Al 0.8 O 4 spinel oxide catalyst which synthesized in this study has excellent catalytic performance for hydrogen production in MSR. Its low CO selectivity makes it a potential catalyst for producing high-purity hydrogen. Graphical
Optimization of the synthesis process parameters of sol-gel method using orthogonal experiment was first applied for CuFe 1.2 Al 0.8 O 4 catalysts in methanol steam reforming (MSR). Its low CO selectivity makes it a potential catalyst for producing high-purity hydrogen.
研究领域:
材料科学
·
催化化学
·
能源化学
·
化学工程
·
纳米技术
✓ 已验证
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2019
·Vol. 220
·期 5
·1800528
·
IF 2.622
Du Beibei,Fan Tiantang,Li Jiafeng,Gong Li,Zhang Qin,Ye Wuyou,Tai Hongyun,Wang Wenxin,Fan Zhongyong
A series of poly( l -lactide)-grafted gelatin (Gel-g-PLLA) copolymers are synthesized by coupling the amino groups of gelatin with different molar masses and the carboxyl endgroup of poly( l -lactide) in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N -hydroxysuccinimide. Fourier transform infrared and nuclear magnetic resonance ( 1 H NMR) data confirm the successful bonding between gelatin and PLLA. Self-assembled micelles of copolymers are prepared by using the direct dissolution method. The size and micellar morphology are determined from dynamic light scattering as well as transmission electron microscopy measurements. Meanwhile, in vitro drug release reveals that Gel-g-PLLA micelles show excellent sustained-release properties when used as the carrier of the anticancer drug paclitaxel. A burst release of about 70% is observed in the first 24 h. All these features, together with the outstanding biocompatibility, make Gel-g-PLLA micelles a promising drug carrier for cancer therapy.
研究领域:
高分子化学
·
纳米技术
·
药学
·
生物医学工程
·
肿瘤学
✓ 已验证
DOI
高影响因子
MACROMOLECULAR RAPID COMMUNICATIONS
·
2018
·Vol. 39
·期 11
·1800048
·
IF 4.441
Shuang Pan,Mingjing Zhu,Luze He,Hongdong Zhang,Feng Qiu,Zhiqun Lin,Juan Peng
An intriguing morphological transition from poly(3-hexylthiophene) (P3HT) 1D nanofibers to 2D nanoribbons enabled by the addition of a series of alkylthiols is reported. First, P3HT 1D nanofibers are formed due to strong anisotropic π–π stacking between planar rigid backbones. Upon the addition of alkylthiols, P3HT nanofibers are transformed into nanoribbons associated with the crystallographic transition from edge-on orientation to flat-on orientation. The content of alkylthiols has a great influence on the P3HT morphology in the solution. The mechanism of such a morphological transformation is discussed based on the interaction between alkylthiols and P3HT chains. This work offers an effective strategy to tailor the crystal morphology and dimension of P3HT, which not only improves the understanding of P3HT crystallization but also may enable such discovery into conjugated polymer-based optoelectronic devices.
研究领域:
高分子化学
·
材料科学
·
凝聚态物理
·
纳米科技
·
有机电子学
✓ 已验证
DOI
高影响因子
CRYSTAL RESEARCH AND TECHNOLOGY
·
2015
·Vol. 50
·期 4
·312-318
·
IF 0.935
Yadong Hu,Yinghua Zhou,Xurong Xu,Ruikang Tang
The evolution of amorphous calcium carbonate (ACC) into crystals in ethanol/water binary solvents under ambient temperature was investigated, and it was found to depend on the volume ratio of ethanol to water (R). Calcite remained dominant when the amount of water was high (R = 1/3). A slight change in the amount of ethanol (R = 3/1) could lead to a dramatic change in the polymorph from calcite to aragonite. However, when poly (allylamine hydrochloride) (PAH) was added at R = 3/1, almost pure vaterite could be obtained, which has a specific morphological variation (from hollow microspheres to cloud-like). This study provides an alternative polymorphic route for the CaCO 3 mineral by using the evolution of ACC in different solvent environments, which provides some useful clues for understanding the importance of kinetic control of the morphologies and polymorphs of a wide range of inorganic materials. In addition, this simple mild phase-controlled synthetic method could be scaled up as a green chemistry route for the industrial production of different polymorphs of CaCO 3 .
研究领域:
材料化学
·
结晶学
·
纳米材料
·
生物矿化
·
绿色化学
·
功能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2012
·Vol. 129
·期 2
·846-852
·
IF 1.289
Hong Yu Yang,Xiu Mei Zhang,Li Jie Duan,Ming Yao Zhang,Guang Hui Gao,Hui Xuan Zhang
A series of environmental pH-responsive block copolymers PEG-polyurethane with tertiary amine groups in the main chain and free carboxyl groups in the side chain were synthesized, including poly(ethylene glycol) (PEG), 1,4-bis (hydroxyethyl) piperazine, 1,6-diisocyanato hexamethylene, and 2,2-dimethylolpropionic acid. The chemical structure, molecular weight, and pH-dependent capacity of pH-responsive PEG-polyurethane were examined by 1 H-NMR, FTIR, gel permeation chromatography (GPC), and an acid-base titration. Moreover, the fluorescent dye fluorescein isothiocyanate was conjugated with PEG-polyurethane by the similar polymerization method and the obtained polymer was measured by ultraviolet visible spectroscopy (UV-vis) and fluorescent spectroscopy. The results indicated that the pH-responsive PEG-polyurethane showed a pH-buffering phenomenon and fluorescent imaging in a range of pH values. As a result, we demonstrated its potential application for optical imaging; however, it is believed that more applications in the areas of biomedicine will be possible owing to its free carboxyl acid terminal residues in the stimuli-responsive polymer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
研究领域:
生物材料
·
分子影像学
·
高分子化学
·
纳米医学
·
药物递送
·
生物传感器
·
转化医学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 135
·期 11
·45974
·
IF 1.86
Wenqi Xian,Lina Song,Baohua Liu,Hulan Ding,Zhao Li,Mengping Cheng,Le Ma
CO 2 copolymer diol-based thermal polyurethane elastomers (PPC-TPU) were prepared by the reaction of CO 2 copolymer diol and methylene diphenyl diisocyanate and chain extender (ethylene glycol/1,4-butanediol/1,6-hexanediol) (EG/BDO/HG). The rheological and mechanical properties of PPC-TPU were analyzed. The effects of shear rate, shear temperature, hard segment content, and variety of chain extender on the properties of PPC-TPU were studied. The results showed that the apparent viscosity (η) of PPC-TPU decreased with the increasing shear rate ( τ ), and the non-Newtonian index ( n ) was less than 1. PPC-TPU exhibited a typical character of pseudoplastic non-Newtonian rheological behavior. The degradation during the processing was obviously inhibited by adding plasticizer and antioxidant. It was also discovered that the apparent viscosity varied with the content of hard segment and chain extender. Under the same temperature (185 °C) and shear rate (50 s −1 ), the apparent viscosity increased considerably with the raise of hard segment content, and the apparent viscosity and tensile strength of PPC-TPU with EG as chain extender was the maximum. It can be seen that with the apparent shear rate increasing, the variation tendency of apparent shear stress levels off, and the nonlinear relationship of τ – γ curve tended to be obvious. PPC-TPU exhibited a typical character of pseudoplastic non-Newtonian rheological behavior. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45974.
研究领域:
高分子材料科学
·
流变学
·
功能高分子
·
生物基聚合物
·
材料力学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 59
·36867-36875
·
IF 3.108
Fangyan Liu,Jia Ni,Hui Hao,Wei Wang,Wei Chen,Lijie Zhang,Chao Zou,Yun Yang,Shaoming Huang
Pd-based nanostructures with stepped facets possess potential applications in many fields, particularly in catalysis. Generally, crystal growth often only allows the formation of nanostructures with energetically non-stepped facets, so it is desirable to develop methods that can be used to prepare Pd-based nanostructures bounded by stepped facets. Herein, penta-fold twinned (PFT) Au@Pd nanobipyramids (NBs) with stepped {100} facets were synthesized through growing Pd on Au decahedral nanoparticles (NPs) in polyol. During the growth of Au@Pd NBs, Br− was a critical factor, because it has appropriate affinity for the Pd atom and adjusted the growth rate ratio along 〈110〉 and 〈100〉, resulting in the formation of Au@Pd NBs with stepped {100} facets. The product shape and size could be tailored by controlling the reaction conditions. Transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), high angle annular dark field (HAADF) imaging and scanning transmission electron microscopy EDS (STEM-EDS) were used to investigate the structure and growth of the Au@Pd NBs. A growth mechanism involving two stages was elucidated. In the first stage, the growth of Pd clearly occurred along both 〈110〉 and 〈100〉. In the second stage, the growth along 〈110〉 was faster than that along 〈100〉. Furthermore, we also demonstrated that the as-prepared Au@Pd NBs had high catalytic activity, compared with Pd nanocubes and Pd–Au–Pd segmental nanorods.
研究领域:
纳米材料化学
·
催化科学
·
无机合成
·
表面科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 24
·16383-16392
·
IF 2.993
Wu Yadong,Wang Fang,Li Xianglong,He Jinmei,Huang Yudong
The synergic effect between each component in composite membrane has created a new concept to fabricate membrane materials and widen their applications. Previous trials have suggested that micrometer-scale aramid fiber (MAF) could be effectively split into nanoscale aramid fiber (NAF) by dissolution in DMSO/KOH. Addressed herein is a time-saving approach to incorporate graphene oxide (GO) together with NAF to fabricate composite membranes through π–π stacking interactions. NAF–GO composite membranes (GO/NAF) containing gradient contents of GO have been prepared using absolute ethanol as proton donor, making the drying process facile and fast. The obtained composite membranes exhibit excellent hydrophilicity and enhanced mechanical performance. The chemical structure, morphology, crystallization and mechanical strength of GO/NAF composite membranes are characterized, respectively, and the hydrophilicity of GO/NAF is also evaluated by static water contact angle measurements. In the case of medium GO content (1 wt%) used in this study, the composite membrane possesses both optimal mechanical performance and better hydrophilicity compared to other supplementations, indicating that absolute ethanol is a promising proton donor for flocculation, which makes the post-treatment process more economic.
研究领域:
材料科学
·
高分子化学
·
纳米技术
·
膜科学
·
表面科学
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Yuzhen Zhang,Jiangying Yu,Changwei Shao,Peichuan Sun,Chungang Min,Jianhua Wang,Xikun Yang
Effectively improving catalytic activity of nitrogen (N)-doped carbon catalysts in oxygen reduction reaction (ORR) is very important but still facing with challenges. Herein, we proposed a “solvent effect” strategy to prepare a high active N-doped carbon catalyst with trace iron (N-C-Fe-ethanol, 0.10 at.% Fe) via pyrolysis of polyaniline (PANI)-iron (Fe) coordination polymer washed with ethanol. Electrochemical results show that N-C-Fe-ethanol catalyst exhibits a remarkable 109 mV positive shift of half-wave potential compared with that of catalyst unwashed PANI-Fe coordination polymer, and its limiting current density (3.61 mA-cm -2 ) is closer to that of Pt/C catalyst in acid media. It was demonstrated that the surface structure of PANI-Fe coordination polymer could be tuned via removing some nitrogen-containing groups such as –N + = groups and other small molecules on its surface, which helped to generate a high ratio of graphitic N in the pyrolysis process. This work develops a new path for improving the ORR activity of N-doped carbon catalysts.
研究领域:
材料化学
·
电催化
·
能源材料
·
纳米催化
·
表面化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2016
·
IF 8.328
Shengjie Xia,Yue Meng,Xiaobo Zhou,Jilong Xue,Guoxiang Pan,Zheming Ni
In this paper, Ti/ZnO–Fe 2 O 3 composite derived from Ti/Schiff base intercalated ZnFe layered double hydroxides was used as thin film electrode in CO 2 photoelectroreduction. The influence of molar ratio of Ti/Fe and calcination temperature, which would affect the composites' physicochemical property and the photoelectrocatalytic performance for CO 2 reduction, were investigated in detail. The characterization results from XRD, SEM, TEM, UV-vis and BET showed that Ti/ZnO–Fe 2 O 3 composite with flower–like crystal from had small particle sizes, narrow band gap and excellent textural properties. The final product of CO 2 photoelectroreduction was methanol and the intermediates were formic acid and formaldehyde. The methanol field reached at 0.773 mmol/cm 2 after 3 h reaction with 0.5 V voltage by Ti/ZnO–Fe 2 O 3 composite with Ti/Fe = 1, calcined at 800 °C. In addition, the CO 2 photoelectroreduction pathway and the reason for highly efficient photoelectrocatalytic activity of the composite were also discussed.
研究领域:
材料化学
·
环境催化
·
能源化学
·
纳米材料科学
·
电化学
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2020
·Vol. 78
·期 8
·4183-4204
·
IF 2.014
Yu Hailin,Xia Yifan,Zhang Hanwen,Wang Yinghan
A novel series of sulfonated polyimide (SPI)/polyvinyl alcohol (PVA) composite membranes applied in vanadium redox flow battery (VRFB) is prepared and characterized in this work. With the hydrophilicity and good barrier of PVA, the composite membranes exhibit better hydrolysis stability and vanadium ion resistance than normal SPIs with five-membered rings. In VRFB single-cell tests, because of the highest proton selectivity, the SPI5/PVA5 composite membrane shows lower self-discharge rate, higher coulombic efficiency, and energy efficiency (EE) (79.5% vs 77.8% at 30 mA cm −2 ) than that of Nafion117. Besides, the composite membranes present stable performances up to 100 cycles without significant decline in EE.
研究领域:
材料科学
·
电化学
·
能源存储
·
高分子化学
·
膜科学与技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）