功能化碳微球构建自组装膜

采用浓HNO3和H2O2对原始CMSs进行表面修饰,使其团聚现象得到改善;以氧化后CMSs作为结构基团,采用垂直沉积法实现CMSs的自组装,得到CMSs薄膜.考察了溶剂、悬浮液pH值、悬浮液浓度和反应温度对自组装的影响.采用场发射扫描电子显微镜和原子力显微镜对产物进行表征分析,结果表明,以NaOH溶液为溶剂配制悬浮液、...     

1,6-己二胺对碳微球的功能化修饰

首先采用体积比为1:3的浓硝酸和浓硫酸对碳微球(CMSs)进行氧化修饰,改善其表面活性;然后在缩合剂N,N'-二环己基碳二亚胺(DCC)的作用下,用1,6-己二胺与氧化CMSs反应,制备胺化CMSs。在胺化过程中考虑缩合剂DCC用量、反应时间和反应温度的影响。采用场发射扫描电子显微镜、热重分析仪和红外光谱仪对各阶段产物进行了形貌和结构的表征与分析。结果表明:对于0.3 g氧化CMSs,DCC用量0.3 g、反应时间36 h和反应温度110℃是胺化反应的适宜条件,所得胺化产物在弱极性溶剂乙酸乙酯和氯仿中有良好的分散性,且能与常用聚合物给体材料(聚3-己基噻吩)能级匹配,有望进一步与聚合物复合,为制备聚合物太阳能电池奠定基础。     

磁性聚醋酸乙烯酯微球的制备及表面功能化修饰

在油酸包覆的Fe3O4磁流体存在条件下,以醋酸乙烯酯为聚合单体,二乙烯苯为交联剂,过氧化苯甲酰为引发剂,聚乙烯醇为稳定剂,采用改良悬浮聚合法制备了粒径在数微米之间的磁性聚醋酸乙烯酯微球,对制备的磁性微球进行了表面功能化修饰。利用扫描电镜、振动样品磁强计和Fourier变换红外光谱分别检测了磁性微球的形貌、磁性能以及微球表面修饰的活性功能基团。结果表明:微球大小在1～7μm,平均粒径为3.8μm,粒径分布相对较窄;比饱和磁化强度为15.0emu/g,具有超顺磁性。     

沉积碳纳米微球制备超疏水表面

通过采用长链脂肪烃混合物在大气环境下的不完全燃烧,将其产生的碳纳米微球沉积在铝合金基底,制备一种具有稳定超疏水性能的表面。该方法简捷高效、所用原料廉价易得、操作简单、无需特殊设备。所制备的超疏水表面不仅对纯水具有很高的接触角,而且对于腐蚀性液滴也保持了很高的接触角。采用透射电镜和扫描电镜分别研究了所制备的超疏水表面的表面形貌以及碳纳米微球的微观结构,结果表明,碳纳米微球在微米尺度上的堆积和其50 nm的直径赋予了表面超疏水性能。     

中间相碳/Co复合微球的制备

以煤沥青和乙酸钴为原料进行热缩聚反应，以吡啶为溶剂，分离制备出大小为20μm左右的中间相碳／Co复合微球，并研究了钴含量和热处理温度对复合微球结构的影响。研究结果表明，随着原料中乙酸钴含量的增加，制备出的复合微球钴含量增加。复合微球的X衍射图显示出明显的石墨碳和金属钴的衍射峰，2500℃石墨化后，复合微球中的钴仍能稳定存在。热处理过程中复合微球中钴对碳的石墨化有催化作用，钴含量越大，这种催化石墨化作用越明显。复合微球的TEM照片显示微球中钴颗粒大小为10～40nm，颗粒均匀分布在中间相碳基质中。     

碳微球的研究进展

从碳微球的制备方法着手,综述了各方法的制备原理、原料、影响因素以及所得碳微球的结构性能和形貌特征,并归纳了各方法的优缺点,得出了溶剂热法、化学气相沉积法和模板法3种相对有效的制备方法,由于溶剂热法的突出优点,在碳微球的多种制备方法中优势凸显,将成为未来制备碳微球的主要方法。详细评述了不同结构和性能的碳微球在各个领域的应用,深入开发碳微球的性能和拓展其应用领域将会成为今后的研究重点;进一步讨论了碳微球的结构对其性质和应用的影响,通过设计碳微球的结构来改变其性质,是碳微球制备研究领域未来的发展方向。     

碳微球的制备及应用研究进展

综述了碳微球的基本制备方法,包括电弧放电法、水热法、化学气相沉积法以及模板法,水热法操作简单,条件温和,微球分散性好,产物纯,在碳微球的制备方法中占有突出优势;介绍了碳微球在电池电极材料、超级电容器以及催化剂载体领域的应用,并展望了未来碳微球的发展方向。     

纳米聚合物微球对石蜡的表面修饰

采用乳液聚合法制备得到单分散且粒径为80～100nm的聚苯乙烯(PS)种子微球,使聚苯乙烯与石蜡进行共聚,合成石蜡聚苯乙烯微球.通过实验对微球合成的因素进行分析,找到了影响微球合成产率及粒径分布的因素.结果表明,乳液聚合法合成的聚苯乙烯粒径较为均匀,分散性好.通过聚苯乙烯对石蜡的修饰得到微米级粒径、分布均匀且高产率的石...     

微纳米多孔碳质材料的表面修饰及苯酚吸附性能

采用不同修饰工艺对微纳米多孔碳质材料进行处理,考察了修饰前后材料表面官能团的变化及其对苯酚吸附能力的影响,并结合Boehm滴定、Fourier变换红外光谱仪和X射线光电子能谱对材料表面官能团进行表征。结果表明：经高温（800℃）和尿素修饰后,材料的比表面积分别下降了41.9%和19.6%,苯酚吸附性能分别提升了21.2%和37%;经硝酸预改性的样品表面存在大量的羧基和酚羟基酸性基团,尿素改性时更利于吡啶和吡咯结构的生成。     

Surface modification of Kevlar by grafting carbon nanotubes

A novel and efficient method was developed for surface‐modification of Kevlar fibers by multi‐wall carbon nanotubes (MWCNTs). Kevlar fibers were immersed in a solution mixed with Hexamethylene diisocyanate, 1,4‐diazabi‐cyclo [2,2,2] octane (DABCO), and toluene to introduce pendant amine groups before the COCl‐functionalized carbon nanotubes were chemically grafted onto the surface of modified fibers under ultrasonic condition. The characterization of resulting fiber involved in SEM, infrared spectroscopy, and tensile measurement. Results indicated over 20% of the fiber surface were coated by MWCNTs even after washing, which indicated a good adhesion. Furthermore, the mean value of tensile strength of Kevlar fiber was improved by 12% compared with original one. And the interlaminar shear strength (ILSS) of the fiber‐reinforced bismaleimides composite was increased by 30%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Surface modification of polybutadiene facilitated by supercritical carbon dioxide

The hydrophilicity of polymers can be improved through surface modification, traditionally done with conventional organic solvents, but these may cause the deterioration of polymer bulk properties due to irreversible polymer swelling. However, supercritical carbon dioxide (scCO₂) not only swells the polymer reversibly, but also acts as a convenient transport medium for monomeric solutes, which may be subsequently polymerized. Thus we are able to modify the polymer surface without affecting its bulk strength and durability. Here we report scCO₂ surface modification of polybutadiene using ultraviolet‐visible (UV/Vis) and Fourier transform infrared (FTIR) spectroscopy. Monomers such as 3‐vinylbenzoic acid and crotonic acid are used to study the effects of pressure, solute structure, and reaction mechanism on the diffusion rates and partitioning of monomers between the fluid phase and the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 522–530, 2003     

Surface modification of multi-wall carbon nanotubes by nitrogen attachment

Commercial multiwall carbon nanotubes (MWCNT-s) were treated by RF activated N₂ gas plasma at (nominally) room temperature. Treatment time of 5 to 10 min was applied at negative bias varying in the 0-300 V range. Surface chemical alterations were followed by X-ray photoelectron spectroscopy (XPS). All the applied treatments resulted in a significant build-up of nitrogen in the surface of MWCNT-s. The amount of nitrogen varied between 19 and 25 at.% depending on the treatment time and, in a lesser extent, also on biasing conditions. Interestingly, the nitrogen attachment was also significant (20 at.%) when the treatment commenced without bias. Evaluating the high-resolution N1s XP spectral region, typically three different chemical bonding states of the nitrogen was delineated. Peak component at 398.3 ± 0.3 eV is assigned to CNC type, at 399.7 ± 0.3 eV to sp² N in melamine-type ring structure and at 400.9 ± 0.3 eV to N substituting carbon in a graphite-like environment. Identical chemical bonding of the nitrogen was detected on the surface of highly oriented pyrolytic graphite (HOPG) and on microcrystalline graphite surfaces treated in the same way for comparison. Estimating the penetration depth of the nitrogen atoms by the SRIM program it was concluded that at the applied DC bias energy range the implanted nitrogen is incorporated in the top 2-4 monoatomic layers of the samples. A model for the distribution of the chemically bonded nitrogen on the outer walls of the MWCNT-s is proposed.     

Surface modification of carbon/carbon composites to improve their wettability by copper

This work proposes a simple and low cost method to modify the surface of undoped and silicon-doped carbon/carbon composites (C/C) in order to widen their application field in particular when joined to metals. The C/C surface was modified using W, Mo and Cr in an attempt to improve its wettability by copper.W, Mo and Cr powders are applied to C/C surface by the slurry technique and successively heat treated in Ar atmosphere to perform a solid state reaction with C/C. As a consequence, Cu wetting on C/C is improved and direct joining of C/C to Cu is feasible without any filler metal. The reactions between the C/C surface and the deposited metal powders were investigated by X-ray diffraction analysis, optical and electron microscopy. The best results in terms of wettability of molten copper on C/C have been achieved by modifying C/C with Cr. Cr forms a homogeneous carbide layer on the C/C surface with strong adhesion which provides a suitable substrate for molten copper. Because of the importance of surface wetting behaviour in certain applications (e.g. joining C/C to metals), C/C surface modification may enhance their use.     

Surface modification of carbon sorbents with polycarbosilane

Modified carbon sorbents containing silicon oxycarbide, which did not form a continuous protective layer on the surface, were prepared by the liquid-phase supporting of polycarbosilane onto the surface of carbon sorbents followed by thermal treatment. The silicon-containing sorbents were characterized by increased stability to oxidation by atmospheric oxygen at high temperatures (as compared with that of the initial sorbents) with the retention of sufficiently high sorption activity.     

Surface modification of amorphous carbon thin films by 1,3-dipolar cycloaddition

Amorphous carbon thin film surfaces were successfully modified by 1,3-dipolar cycloaddition of nitrones, generated by the condensation of 4-(trifluoromethyl)benzaldehyde and N-methylhydroxylamine. Amorphous carbon thin films were deposited by electron cyclotron resonance sputtering and consisted of mainly sp²-hybridized carbon. The modification of amorphous carbon thin film surfaces with organic molecules was confirmed by X-ray photoelectron spectroscopy (XPS), Raman, and atomic force microscopy (AFM). F 1s, N 1s, and C 1s electron spectra revealed the existence of organic molecules on the surface of modified amorphous carbon thin films. The surface coverage increased with reaction temperature, reactant concentration, and reaction time.     

Surface modification and characterization of carbon spheres by grafting polyelectrolyte brushes

Modified carbon spheres (CSPBs) were obtained by grafting poly(diallyl dimethyl ammonium chloride) (p-DMDAAC) on the surface of carbon spheres (CSs). It can be viewed as a kind of cation spherical polyelectrolyte brushes (CSPBs), which consist of carbon spheres as core and polyelectrolytes as shell. The method of synthesizing carbon spheres was hydrothermal reaction. Before the polyelectrolyte brushes were grafted, azo initiator [4,4′-Azobis(4-cyanovaleric acyl chloride)] was attached to the carbon spheres'' surface through hydroxyl groups. CSPBs were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), conductivity meter, and system zeta potential. The results showed that compared with carbon spheres, the conductivity and zeta potential on CSPBs increased from 9.98 to 49.24 μS/cm and 11.6 to 42.5 mV, respectively, after the polyelectrolyte brushes were grafted. The colloidal stability in water was enhanced, and at the same time, the average diameter of the CSPBs was found to be 173 nm, and the average molecular weight and grafted density of the grafted polyelectrolyte brushes were 780,138 g/mol and 4.026 × 10⁹/nm^2, respectively.     

Surface modification of thermally expandable microspheres for enhanced performance of disbondable adhesive

This research successfully improved the compatibility between thermally expandable microspheres (TEMs) and an adhesive system for enhanced performance. TEMs were grafted with poly(glycidyl methacrylate) (PGMA) chains via atom transfer radical polymerisation (ATRP) with activators regenerated by electron transfer (ARGET) or ARGET ATRP technique. The temperature effect on the surface modification of TEMs was investigated for an optimum modification condition. Compared to adhesive incorporating unmodified TEMs, up to 15.8% increase in tensile lap shear strength and 24.0% increase in ultimate tensile strength (UTS) were achieved. Most notably, after environmental conditioning, the UTS of the adhesive system containing modified TEMs was 8.0% higher than the strength of unmodified TEMs before environmental conditioning.