ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
·
2013
·Vol. 39
·期 1
·43-51
·
IF 0.385
Ahmad Nadeem,Khan M. B.,Ma Xiaoyan,Ul-Haq Noaman
Cross-linked and chain-extended polyurethane networks based on hydroxyl-terminated polybutadiene are synthesized by one-step reaction with isophorone diisocyanate. The degree of cross-linking is controlled by varying the triol to diol ratio. Chain extension is optimized by appropriate adjustment in the concentration of the diols. The influence of cross-linking agents and chain-extenders on mechanical properties of cured elastomers is investigated. IR-spectroscopy is employed to observe the curing reaction and inter-segment hydrogen bonding. It is demonstrated that the chain-extended polymer is phase segregated at sub-micron level and registers far better mechanical properties as compared to cross-linked polymer. Incorporation of 1,4 butanediol yields the maximum tensile strength, elongation and modulus. The polymer fabricated with trimethylolpropane is stronger than that of hexanetriol but exhibits lower stretching properties. However, butanediol exhibits superior mechanical properties in comparison to hexanediol. Equilibrium swelling behaviour follows the expected norm; degree of swelling varies inversely with the cross-link density. The chain-extended polymers show reduced degree of swelling due to plausible association between the hard segment domains formed in the micro-phase segregated structures.
研究领域:
高分子材料科学
·
功能高分子
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聚合物化学
·
材料力学
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软物质物理
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高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2018
·Vol. 411
·期 2
·471-478
·
IF 3.307
Huang Lu,Lin Qi,Li Yanxia,Zheng Guocai,Chen Yiting
Two new chiral membranes were prepared by modification of gold nanochannel membranes with d -penicillamine and N -acetyl- l -cysteine and were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. The effects of key factors such as the gold deposition time, the pH, and the concentration of sodium dihydrogen phosphate on the separation factor are discussed. Chiral resolution of amino acid enantiomers by the chiral membranes was investigated. The experimental results show that the d -penicillamine-modified membrane has good enantioselectivity toward tyrosine and phenylalanine enantiomers, whereas the N -acetyl- l -cysteine-modified membrane has good enantioselectivity toward tyrosine and tryptophan enantiomers. Furthermore, the chiral recognition mechanism was studied by density functional theory. The calculation results indicate that the basic chiral recognition system of d -penicillamine complexes involves only one chiral selector and one selected enantiomer, whereas that of N -acetyl- l -cysteine complexes involves two chiral selectors and one selected enantiomer. Finally, the NH 3 + group of d -penicillamine is proved to play an important role in enhancing interactions between complexes and improving enantioselectivity.
Enantioselective interactions between amino acid enantiomers and sulfhydryl-compound-functionalized gold nanochannel membranes
研究领域:
分析化学
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纳米科学与技术
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分子识别
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手性分离
·
生物传感器
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Zuolong Yu,Guiwei Rao,Yunxiao Wei,Jie Yu,Sihong Wu,Yupei Fang
Of late, the demand for food-packaging materials, in particular, multifunction packaging materials that are biodegradable; antibacterial; have good mechanical and barrier properties; and are edible and transparent, has increased considerably. In this study, we prepared chitosan (CS)/ε-polylysine (PL) biofilms with different CS-to-PL ratios. We studied the preparation, mechanical properties, microstructures, thermal stability, transparency, water-vapor permeability, oil permeability, and antibacterial properties of the composite CS/PL biofilms. The results demonstrate that CS/PL biofilms are mechanically strong, have good thermal stability, high transparency, low water-vapor and oil permeability, and extensive antibacterial properties that act against Escherichia coli , Bacillus subtilis , and yeast. Therefore, we therefore conclude that CS/PL biofilms are promising food-packaging materials.
研究领域:
高分子材料科学
·
食品科学
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包装工程
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生物医学工程
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应用微生物学
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材料表征
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食品安全
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DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2011
·
IF 1.862
Xin Liu,Kai Xu,Huan Liu,Hualun Cai,Jiangxun Su,Zien Fu,Ying Guo,Mingcai Chen
Waterborne polyurethanes (WPUs) with natural dimer fatty acids (DA) based polyester polyols as soft segments were prepared via the acetone process, and characterized by Fourier transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC). The thermal and mechanical properties were investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and tensile tester. Water contact angle on the surface of the WPU films increased from 80° to 93° with increasing DA weight content in dicarboxylic acid of polyester polyol from 0 to 100%. The results indicated that among the synthesized WPUs, those containing DA exhibited excellent water resistance (water uptake decreased from 13.2% to 2.42%), outstanding hydrolytic resistance (weight loss decreased from 14.2% to 5.85%) and superior thermal stability (decomposition temperature of 50% weight loss and maximum weight loss, increased from 384 to 443 °C and from 409 to 464 °C, respectively). Compared to toluene resistance and mechanical properties of WPUs containing no DA, those of WPUs containing DA were low. For the WPU films based on polyester polyol derived from 100% DA as dicarboxylic acid, the interesting delamination occurred in special solvents, probably due to dissolution of low molecular weight molecules, and the presence of long hydrophobic branched chains and the high degree of phase separation.
研究领域:
高分子材料
·
涂料科学
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表面化学
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胶体与界面科学
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功能材料
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环境友好材料
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高影响因子
RSC Advances
·
2017
·Vol. 7
·期 67
·42320-42328
·
IF 3.108
Zaochuan Ge,Huanhuan Ren,Shuqin Fu,Shaojun Chen
Recently, zwitterionic shape memory polyurethanes (ZSMPUs) have found many promising applications in smart biomedical field. This paper provides a novel strategy to improve shape memory properties of ZSMPUs by using a silane coupling agent, namely 3-glycidyloxypropyl-trimethoxysilane (KH560). The synergistic effects of zwitterionic segments and silane coupling agents on the structure, morphology, thermal properties, mechanical properties, and shape memory properties were carefully investigated. The results demonstrate that the incorporation of KH560 does not influence the original molecular structure and morphology of ZSMPUs, and the KH560-modified ZSMPUs form a hard–soft phase separation structure. Also, the KH560 modification promotes the entanglement of hard segments, and thus provides better mechanical properties to ZSMPUs-KH560. Moreover, the silane coupling agent can provide lubrication to influence the aggregation of soft segments while the zwitterionic segments promote the formation of crystal seeds. Therefore, a good semi-crystalline soft phase endows the ZSMPUs-KH560 with a decent shape fixity (e.g. above 94%), and the entangled hard segments greatly enhance the shape recovery of ZSMPUs (e.g. above 90%).
研究领域:
生物材料学
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高分子科学
·
生物医学工程
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智能材料
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组织工程
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药物递送
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表面科学
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高影响因子
Polymer Chemistry
·
2016
·Vol. 7
·期 10
·1963-1970
·
IF 5.687
Dedai Lu,Yongyong Zhang,Ting'e Li,Yunfei Li,Hongsen Wang,Zhiqiang Shen,Qiangbing Wei,Ziqiang Lei
The incorporation of L-3,4-dihydroxyphenylalanine (L-DOPA) residues in mussel-like biomimetic copolymers has drawn great attention due to their adhesive properties. In this work, a series of temperature-sensitive and hyperbranched poly(amino acid)s containing different functional side groups (catechol, guanidyl, mercapto and double bond) were designed and synthesized by the ring-opening polymerization of N-carboxy-α-amino acid anhydride (NCA), using a temperature-sensitive and multi-hydroxyl end pluronic L-31 as the initiator in this process. The tissue adhesive properties of these copolymers were evaluated by tensile strength tests on wet pork skin. We found that the topological structure, side groups of copolymers, adhesive temperature and cure time had influence on the wet adhesive strength, especially side groups. While only L-DOPA was incorporated into copolymeric chains, the wet adhesive strength was about 106 kPa. With guanidyl, mercapto and double bonds incorporated into copolymeric chains, an obvious increase in the wet adhesive strength was observed. Additionally, the wet adhesive strength improved by about 20 kPa at body temperature (37 °C) as compared to that at room temperature (25 °C). Meanwhile, we found that it has good biocompatibility and degradability through its cytotoxicity and degradation tests.
研究领域:
生物材料学
·
高分子科学
·
组织工程
·
再生医学
·
生物医学工程
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药物递送
·
表面科学
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高影响因子
RARE METALS
·
2012
·Vol. 31
·期 5
·512-516
·
IF 0.593
Lian Yuanpei,Zhen Wei,Tai Zhigang,Yang Yaling,Song Jun,Li Zonghao
Cloud point extraction (CPE) with Tergitol TMN-6 was applied for the extraction of trace amounts of palladium (Pd(II)), platinum (Pt(IV)), and gold (Au(III)) in the soil of industrial sewage. Ammonium pyrolysine dithiocarbamate (APDC) was adopted as the chelating agent prior to CPE and then was detected by atomic absorption spectrometry (AAS). Different parameters such as the concentration of surfactants, chelating agent and salt, sample pH, equilibration temperature and time, centrifugation time and rates, and the effect of foreign ions were studied. Under optimum conditions, the low limits of detections are 1.4, 2.8 and 1.2 ng·ml −1 and the enrichment factors are 21, 12, and 24 for Pd(II), Pt(IV), and Au(III), respectively. The relative standard deviations vary from 0.6% to 1.0% ( n =11). All correlation coefficients of the calibration curves are >0.9960. The proposed method was successfully applied for the determination of Pd(II), Pt(IV), and Au(III) in the real soil of industrial sewage samples.
研究领域:
分析化学
·
环境化学
·
重金属检测
·
分离科学
·
环境监测
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高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2015
·Vol. 41
·期 11
·8557-8570
·
IF 1.221
Wu Jinfang,Zheng Xingwen,Li Wenpo,Yin Linliang,Zhang Shengtao
The work presents the combined effect of methionine molecules and cuprous oxide passive film on the corrosion inhibition of copper in 1 M NaOH solution by using potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy/energy dispersive X-ray analysis and theoretical calculations. The results reveal that methionine is an effective inhibitor for copper in 1 M NaOH solution and its inhibition efficiency is increased by increasing its concentration. Also, the electrochemical results showed that methionine mainly suppresses the cathodic process as a cathodic-typed inhibitor by adsorption, and the adsorption of methionine can occur on the passive film surface (cuprous oxide) of copper. The adsorbed film of inhibitors combines with the cuprous oxide passive film, and provides a double-layer protection for copper in alkaline solution. Quantum chemical calculation was applied to investigate the inhibition mechanism of methionine, and molecular dynamics simulation was further performed to illustrate the double-layer protection system for copper in alkaline solution.
研究领域:
材料科学
·
电化学
·
腐蚀与防护
·
表面科学
·
理论化学
·
金属材料
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DOI
高影响因子
Nano Research
·
2023
·Vol. 16
·期 8
·10770-10778
·
IF 9.9
Guan Renquan,Cheng Xueying,Chen Yunning,Wu Zhengkai,Zhao Zhao,Shang Qingkun,Sun Yingnan,Sun Zaicheng
Ammonia is an important chemical raw material and non-carbon-based fuel. Photocatalytic ammonia production technology as a mild alternative to the traditional Harbor–Bosch route is carried out at the air, liquid, and solid three-phase interface. Promoting the activation of N 2 , depressing hydrogen evolution reaction (HER), and increasing the local N 2 concentration around the catalyst surface are critical factors in achieving high conversion efficiency. In this paper, we proposed that defective TiO 2 is surface-modified by alkyl acids with different carbon chain lengths (C 2 , C 5 , C 8 , C 11 , and C 14 ) to tune the catalyst surface properties. The defect sites greatly promote N 2 adsorption and activation. The wettability of the catalyst can be regulated from hydrophilic to hydrophobic by the length of the alkyl chain. The hydrophobic surface enhances the N 2 adsorption and increases the local N 2 concentration due to its aerophile. Meanwhile, it depresses the proton adsorption and HER. Overall, the nitrogen reduction reaction (NRR) is greatly promoted. Among the series of samples, they present a systematic change and have a maximal NRR performance for n-octanoic acid-defective TiO 2 (C 8 -Vo-TiO 2 ; Vo = oxygen vacancy). The rate of ammonia production can be as high as 392 µmol·g −1 h −1 . This work provides a new strategy for efficient ammonia synthesis at the three-phase interface using photocatalyst technology.
研究领域:
光催化
·
材料科学
·
化学工程
·
环境科学
·
表面化学
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DOI
高影响因子
ELECTROCHIMICA ACTA
·
2010
·Vol. 55
·期 23
·7102-7108
·
IF 3.325
Huanshun Yin,Qiang Ma,Yunlei Zhou,Shiyun Ai,Lusheng Zhu
The graphene–chitosan composite film modified glassy carbon electrode (GCE) was fabricated and used to determine 4-aminophenol (4-AP). In 0.1 M pH 6.3 phosphate buffer solution , the redox peak currents of 4-AP increased significantly and the peak-to-peak separation decreased greatly at graphene–chitosan composite film modified GCE compared with bare GCE and chitosan modified GCE, indicating that graphene possessed electrocatalytic activity towards 4-AP. The experimental conditions were optimized and the kinetic parameters were investigated. The oxidation mechanism was discussed. Under the optimal experimental conditions, the oxidation peak current was proportional to 4-AP concentration in the range from 0.2 to 550 μM with the correlation coefficient of 0.9930. The detection limit was 0.057 μM (S/N = 3). Using the proposed method, 4-AP was successfully determined in water samples and paracetamol tablets with standard addition method, suggesting that this method can be applied to determine 4-AP in environments and pharmaceuticals.
研究领域:
电分析化学
·
药物代谢
·
环境监测
·
生物传感器
·
分子诊断
·
转化医学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE
·
2017
·Vol. 28
·期 5
·67
·
IF 2.325
Li Wenyan,Huo Mengmeng,Sen Chaudhuri Arka,Yang Chen,Cao Dazhong,Wu Zhenghong,Qi Xiaole
Currently, polysaccharide-based hydrogels are widely studied macromolecular networks to modify drug dissolution from controlled-releasing matrix tablets. Among them, polyelectrolyte complexes (PEC) films consisted of chitosan (CS) and sodium alginate (SA) could be obtained via spontaneously assembling under physiological gastrointestinal environment. Here, we utilized these self-assembled PEC films as an efficient coating materials to develop controlled-released matrix tablets through compression coating process, with paracetamol (APAP) as model drug. The constitutive and morphology characteristic studies on these PEC films illustrated that the mixture of CS and SA with the weight ratio of 1:1 would be an promising outer layer for compression-coating tablets. In addition, the in vitro drug releasing behavior experiments demonstrated that the optimized compression coating tablets displayed satisfied zero-order drug releasing profits. Furthermore, the in vivo pharmacokinetic studies of these APAP loaded compression-coated tablets in New Zealand rabbits gave that the T max (12.32 ± 1.05 h) was significantly prolonged ( p < 0.01), compared to that (0.89 ± 0.26 h) of common APAP tablets (Jinfuning ® ) after oral administration. These studies suggest that the compression-coated tablets with self-assembled PEC film as coating outer layer may be a promising strategy for peroral controlled release delivery system of water soluble drugs. Graphical
研究领域:
药剂学
·
生物材料
·
药物递送系统
·
药代动力学
·
胃肠药理学
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DOI
高影响因子
Materials Today Chemistry
·
2021
·
IF 8.301
Z. Yu,Y. Yang,C. Wang,G. Shi,J. Xie,B. Gao,Y.C. Li,Y. Wan,D. Cheng,T. Shen,S. Hou,S. Zhang,X. Ma,Y. Yao,Y. Tang,J. Chen
Although various eco-friendly and sustainable biobased polyurethane-coated controlled-release fertilizers (BPCFs) have been developed, their applications were limited by the bio-based coating contained many microscopic holes. In this work, a nano-soy-protein microcapsule-enabled self-healing biopolyurethane-coated controlled-release fertilizer (NSBCF) with enhanced controlled-release performance was fabricated. Nanoscale soy-protein microcapsules (SMCs) were prepared from soy-protein isolate (SPI) and poly (lactic-co-glycolic acid) using the water-oil-water emulsification technology. The self-healing biopolymer coatings of NSBCF with uniformly dispersed SMCs were constructed through self-assembly. The controlled-release longevity of NSBCF was >28 days longer than that of the BPCF with the unmodified coating. The self-healing mechanism of NSBCF was determined by directly observing the restoration area and the 3D pore distribution of coating using fluorescence labeling and X-ray computed tomography . After being released from the SMCs, SPI self-repaired the coating by reacting with glutaraldehyde to form solid resins to clog the microscopic holes. The SMCs-enabled self-healing process successfully reduced the nutrient release rate and extended the nutrient release longevity of NSBCF. This novel biobased controlled-released fertilizer with self-healing function represents a new direction for the development of high efficiency and environmentally friendly fertilizers to improve agriculture and food sustainability .
研究领域:
农业材料学
·
环境功能材料
·
可持续农业
·
高分子化学
·
缓释技术
·
生物基材料
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DOI
高影响因子
危险品化学品经营许可证（带存储）