Surface oxidation of cellulose fibers by vacuum ultraviolet irradiation

The efficacy of vacuum ultraviolet irradiation for oxidizing the surface of cellulose fibers was compared to that of the conventional wet and dry processes. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 357–361, 1999     

Surface modification and characterization of carbon black through oxidation

This study focuses on modifying the surface of carbon black (CB) with hydrogen peroxide to raise light absorbance of dispersed CB in water without capping agent. Four kinds of commercial CB, trademarked as M900, M1000, M1100, and Mogul L, respectively, were used as study materials. The ultrasonic bath was utilized to disperse the treated CB in de-ionic (DI) water in the absence of capping agent. The surface properties of treated CB were characterized by thermal gravimetric analysis, X-ray photoelectron spectroscope, and Fourier transform infrared spectroscopy, as well as the light absorbance, stability, and morphology of treated CB particles dispersed in DI water were analyzed by ultraviolet-visible light absorption spectroscopy, dynamic light scattering, and transmission electron microscopy. As shown in the results, in particular, it was found that the oxygen on the surface of CB could be increased by the treatment of peroxide hydrogen, resulting in stable dispersion without capping agent to sharply increase light absorption value of Mogul L CB in DI water from 38 to 545 g⁻¹ dm².     

Surface modification and characterization of carbon black by sodium lignosulphonate

Carbon black (CB) was encapsulated by the sodium lignosulphonate via the strong π–π* interaction force of aromatic ring in the planetary ball milling instrument. The use of new surfactant and ball milling instrument met the requirements about the low‐cost standard and provided an important sense to industrialization in comparison with the old surfactant, the poly(sodium 4‐styrenesulfonate). The successful encapsulation was confirmed by Raman spectroscopy, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and thermal gravimetric analysis. Encapsulation ratio of the modified CB increased to 15.9% when CB was prepared at longer milling time and with agate balls in different size. The morphology and dispersibility of samples studied by transmission electron microscope, sedimentation experiment and ultraviolet–visible spectroscopy showed that the modified CB dispersed stably in the deionized water. The average diameter and absolute value of zeta potential of the modified CB decreased and increased compared with those of CB, respectively, which confirmed further that sodium lignosulphonate encapsulated on the surface of CB make CB disperse better. In addition, the average diameter and zeta potential of the samples were affected by ball milling conditions. The modified CB prepared at longer milling time and with different sizes of agate balls had better dispersibility than the ones prepared at shorter milling time and with same size of agate balls. Copyright © 2016 John Wiley & Sons, Ltd.     

Nitric acid oxidation on carbon dispersion and suspension stability

In this study, we have investigated the effect of nitric acid oxidation on the dispersion and suspension stability of activated carbon powder. We treated activated carbon powder with nitric acid at different concentrations. We measured the content of functional groups, the zeta potential and the powder particle size of the activated carbon powder with the Boehm titration, Fourier transform infrared spectroscopy, a zeta potential analyzer, and scanning electron microscopy. The results show that with the increase of nitric acid molar concentration, the content of acid functional groups increased, whereas the content of alkali functional groups decreased. At a nitric acid concentration of 10 mol/l, the surface‐modified activated carbon powder displays features such as the highest functional group content and zeta potential value, the smallest particle size, and the best dispersion and suspension stability in the solution. Copyright © 2008 John Wiley & Sons, Ltd.     

Surface modification of carbon fiber for improving the interfacial adhesion between carbon fiber and polymer matrix

In this study, the reinforcing mechanism of amine functionalized on carbon fibers (CFs) has been precisely discussed, and the differences between aliphatic and aromatic compounds have been illustrated. Polyacrylonitrile‐based CFs were functionalized with ethylenediamine, 4,4‐diaminodiphenyl sulphone, and p‐aminobenzoic acid (PAB), and CF‐reinforced epoxy composites were prepared. The structural and surface characteristics of the functionalized CFs were investigated using X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT‐IR), and scanning electron microscopy (SEM). Mechanical properties in terms of tensile and flexural strengths and moduli were studied. The FT‐IR results confirm the success in bonding amines on the CF surface. After treatment of CFs, the oxygen and nitrogen contents as well as the N/C ratio showed an increase. XPS results provided evidence of the chemical reaction during functionalization, rather than being physically coated on the CF surface. Chemical modification of CF with diamines led to considerable enhancement in compatibility of CF filaments and epoxy resin, and remarkable improvements were seen in both tensile and flexural properties of the reinforced composites. SEM micrographs also confirmed the improvement of interface adhesion between the modified CFs and epoxy matrix. Finally, it can be concluded that PAB is a promising candidate to functionalize CF in order to improve interfacial properties of CF/epoxy composites. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of surface synergy for the dispersion of short carbon fibers sized by adipic acid modified epoxy resin potassium

The carbon fiber (CF) surface plays a critical role in the performance of CF composite materials. Adipic acid modified epoxy resin potassium (AAEK) prepared with epoxy resin and adipic acid, and KOH was employed as the CF sizing agent. Then, series of surface properties of AAEK‐treated carbon fiber (CF‐AAEK) including surface charge, morphology, and groups were characterized by using Faraday cup, friction coefficient gauge, atomic force microscopy, X‐ray photoelectron spectroscopy, and thermogravimetry. The results indicated that the dispersion coefficient of CF‐AAEK was increased by 1.72 times and there were synergistic effects for the dispersion of short CFs during the sizing treatment process with AAEK. In addition, the flexural strength of treated short CF composite proved to increase by 168%, which evaluated that the better CF dispersion in the matrix was a critical factor for the mechanical property improvement of short CF‐AAEK/epoxy resin composites.     

Electrochemical behavior of glassy carbon electrodes modified by electrochemical oxidation

Glassy carbon electrodes were modified electrochemically by pretreatment in sulfate, phosphate or carbonate solutions by means of cycling the potential well into the positive limit of the solvent. Electrodes treated in this manner were then used to incorporate and concentrate a variety of redox species that were either cations or aromatic containing compounds, including Ru(bpy)²⁺₃, Ru(NH₃)³⁺₆, Cu(NH₃)²⁺₄, ferrocene, methylviologen, 1,4-benzoquinone, anthraquinone-2-sulfonate, riboflavin, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Surface-equivalent concentrations ranged from 5 × 10^?9 to 1 × 10^?7 mol cm^?2 for electrodes pretreated for 10 min in sulfuric acid. An E_1/2 vs. pH study of 1,4-benzoquinone, riboflavin, FMN and FAD in modified electrodes shows that the pK_a values shift toward higher pH (nearly 2 pH units). Results concerning the incorporation of redox compounds detected only by mediation with other electroactive complexes and the study of the modified electrodes in electrocatalysis are also discussed.     

碳纤维表面改性研究进展

碳纤维因其优异的综合性能常被用作树脂基体的增强材料.然而由于碳纤维与树脂基体之间的界面结合性能较差,其增强的复合材料的力学性能往往与理论值相差甚远,因此必须对碳纤维进行表面改性,以提高其与聚合物基体的界面粘结性能.本文作者综述了国内外关于碳纤维表面改性技术的研究进展,概述了涂层法、氧化法、高能辐射法等改性方法对碳纤维增强复合材料界面强度的改性效果.     

Surface modification and characterization of phenanthroline nanofilms on carbon substrate

Modification of glassy carbon (GC) surfaces with phenanthroline derivatives (PDs) such as 5‐amino‐1,10‐phenanthroline (5AP) and 5,6‐diamino‐1,10‐phenanthroline (56DAP) is described in this study. Surface modification experiments were performed by cyclic voltammetry (CV) scanning from + 1.2 to + 2.7 V at scan rate of 100 mV/s applying 30 potential scans in acetonitrile (CH₃CN) containing 1 mM PDs and 100 mM tetrabutylammoniumtetrafluoroborate (TBATFB). The presence of PDs on GC electrode was confirmed using CV, electrochemical impedance spectroscopy (EIS), contact angle measurements and ellipsometry and comparing with the results of bare GC electrode. A mechanism was proposed for the electrochemical modification of the GC electrode surface with PDs. The structure of the 5AP and 56DAP films was also discussed in the light of electrochemical and spectroscopic data. The complex‐forming ability of the modified surfaces against metal cations was investigated by square‐wave voltammetry (SWV). It was shown that surfaces having 1,10‐phenanthroline ligands with different functional groups were quite useful for the determination of transition metal ions. Copyright © 2010 John Wiley & Sons, Ltd.     

Textural characteristics, surface chemistry and oxidation of activated carbon

Numerous researches were reviewed and interpreted to depict a comprehensive illustration of activated carbon and its behavior towards oxidation. Activated carbon as one of the most important adsorbents is tried to be described in this review paper by terms of its "Textural Characteristics" and "Surface Chemistry". These two terms, coupled with each other, are responsible for behavior of activated carbon in adsorption processes and in catalytic applications. Although as-prepared activated carbons are usually non-selective and their surfaces suffer from lack of enough reactive groups, their different aspects may be improved and developed by diverse types of modifications. Oxidation is one of the most conventional modifications used for activated carbons. It may be used as a final modification or as a pre-modification followed by further treatment. In this paper, methods of oxidation of activated carbon and other graphene-layer carbon materials are introduced and wet oxidation as an extensively-used category of oxidation is discussed in more detail.     

改性活性炭纤维可见光催化联合脱硫脱硝的研究

利用水合肼还原法制备的TiO₂/Cu₂O复合光催化剂对活性炭纤维(ACF)进行改性,利用SEM、XPS、BET以及XRD对其进行表征,研究改性后ACF的性质及其脱硫脱硝效果。研究表明,TiO₂/Cu₂O同时改性后的ACF表面孔径减小,但表面石墨碳和羰基(C=O)官能团增加,增强了ACF对NO和SO₂的吸附能力,从而提高了脱硫脱硝的效率,该催化剂在40℃、可见光的催化下脱硫效率达90%,脱硝效率达60%。     

Surface characteristics of carbon fibers modified by direct oxyfluorination

The effect of oxyfluorinated conditions on the surface characteristics of carbon fibers was investigated. Infrared (IR) spectroscopy results indicated that the oxyfluorinated carbon fibers showed carboxyl/ester groups (CO) at 1632 cm(-1) and hydroxyl groups (OH) at 3450 cm(-1) and had a higher OH peak intensity than that of the fluorinated ones. X-ray photoelectron spectroscopy (XPS) results for the fibers also showed that oxyfluorination introduced a much higher oxygen concentration onto the fiber surfaces than fluorination with F(2) only. Additionally, contact-angle results showed that the surface was better wetted by following oxyfluorination and that the polarity of the surface was increased by increasing the oxyfluorination temperature.     

二苯氨基碳酰肼在多壁碳纳米管修饰电极上的电催化氧化及电化学动力学研究

肼及其衍生物被广泛应用于医药,农药,水处理,军事,航天,光稳定剂以及化工生产助剂等诸多领域。因此对肼及其衍生物的研究有着极其重要的意义。二苯氨基碳酰肼(二苯氨基脲,又名二苯卡巴肼,D iphenyl Carbazide,DPC)广泛用于重金属离子的检测分析[1-4]。但是,目前关于DPC的电化学     

Preparation of glass carbon electrode modified with nanocrystalline nickel-decorated carbon nanotubes and electrocatalytic oxidation of methanol in alkaline solution

Nanocrystalline nickel with an average diameter of about 16 nm and a face-centered cubic (fcc) structure was uniformly attached to the surface of carbon nanotubes (CNT) by wet chemistry. The sample was characterized by X-ray powder diffraction and transmission electron microscopy (TEM). A glass carbon electrode modified with nickel-modified multi-wall carbon nanotubes (MWCNTs-Ni/GCE) was prepared. The electrochemical behavior of the MWCNTs-Ni/GCE and the electrocatalytic oxidation of methanol at the MWCNTs-Ni/GCE were investigated by cyclic voltammetry in 1.0 mol/L NaOH solution. The cyclic voltammograms showed that the electron transfer between β-Ni(OH)₂ and β-NiOOH is mainly a diffusion-controlled quasireversible process, and that the electrode has high catalytic activity for the electrooxidation of methanol in alkaline medium, revealing its potential application in alkaline rechargeable batteries and fuel cells. __________ Translated from Chinese Journal of Applied Chemistry, 2007, 24(5): 503–506 [译自: 应用化学]     

Surface modification of ultra‐high molecular weight polyethylene fibers by chromic acid

Ultra‐high molecular weight polyethylene (UHMWPE) fibers were modified by chromic acid. The effects of surface modification were evaluated with Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), contact angle measurement, and scanning electron microscope (SEM). The results showed that both the content of O‐containing functional groups and surface roughness of modified fibers increased. The polar groups on the modified fiber surface decreased the contact angles with water and ethylene glycol, as evidenced by contact angle measurement. The tensile test results showed the strength and the elongation at break of UHMWPE fibers decreased but the modulus increased after chromic acid modification. Copyright © 2016 John Wiley & Sons, Ltd.     

Surface and interface study of ZnO nanoparticles modified by octadecanol phosphate

In this paper, we describe an effective method in which ZnO nanoparticles were prepared through the rapid precipitation transformation reaction in aqueous solution of ZnSO₄ and NaOH with octadecanol phosphate (ODP) as a modifying agent. From the study on the surface and the interface, ZnO nanoparticles modified by ODP exhibited small size, pore structure, good dispersion, and hydrophobicity. The wide variety of surface wettability can be achieved by changing the preparation parameters. The research offers a simple and effective approach to prepare ZnO filler in mild condition and enhances interfacial compatibility between ZnO powders and matrixes by treating the surface with certain capping molecules. Copyright © 2010 John Wiley & Sons, Ltd.     

碳纤维表面的液相氧化处理改性

碳纤维表面的液相氧化处理改性赵东宇＊李滨耀余赋生（中国科学院长春应用化学研究所长春１３００２２）关键词碳纤维，表面改性，氯酸钾，硫酸１９９６－１０－２４收稿，１９９７－０５－２９修回＊现在黑龙江大学化学系（哈尔滨，１５００８０）碳纤维具有高强、高模、...     

催化湿式共氧化法同时去除硝基苯和苯酚

在150–210 oC,1.0 MPa氧分压条件下,对催化湿式共氧化法同时去除硝基苯和苯酚进行了研究.与无催化剂共氧化降解苯酚和硝基苯相比,均相催化剂的加入极大提高了苯酚和硝基苯的去除.在所研究的过渡金属催化剂中, Cu2+, Co2+和Ni2+是有效的催化剂,其中Cu2+的催化活性最好.引发剂苯酚的连续加入模式对硝基苯的去除有很大的促进作用,分批加入苯酚的促进作用更明显.在200 oC,以Cu2+为催化剂,苯酚分两次加入,反应1 h,硝基苯去除率达到95%.这种催化共氧化体系以及分批进样引发剂的反应模式对有效去除环境中其它有机污染物提供了一种方法.     

活性炭催化氧化脱除单质汞的研究

模拟煤气的气氛,在硫化氢（H₂S）和氧气（O₂）存在条件下,对活性炭催化氧化吸附单质汞（Hg⁰）的性能进行了研究。结果表明,H₂S和O₂存在条件下,活性炭对Hg⁰的吸附能力明显提高。在180min内,H₂S和O₂共存气氛下,脱汞效率约为78%;只有H₂S存在下,脱汞效率约为69%;没有H₂S和O₂气氛下活性炭脱汞效率快速下降为28%。随着吸附温度的升高,入口汞浓度的提高和吸附剂粒径的增大,活性炭的脱汞效率会随着下降。通过XRD表征表明,Hg⁰的吸附反应机理是Hg⁰在活性炭催化氧化下与H₂S形成硫化汞（HgS）,从而实现了Hg⁰的稳定化脱除。     

Surface characterization of modified glass fibers by inverse gas chromatography

The dispersive component of the surface free energy _d ^s of glass fibers and their acid-base interaction can be evaluated by the measurement of specific retention volumes of several kinds of probe molecules by use of an inverse gas chromatography. The effect of the treatment of glass fibers with silane-coupling agents was also evaluated. The specific retention volumes of n-alkanes changed linearly with theirC number or vapor pressure. Those of polar molecules varied with their donor number (DN) or acceptor number (AN). The _s ^d values and electron-accepting or donating abilities depended upon the kind of functional groups contained in the coupling agents.