CTAB改性石墨/氟碳导电涂层的制备及性能研究

针对目前接地网材料的严重腐蚀问题,研究一种高性能导电防护涂层。以氟碳树脂(FEVE)为成膜剂,采用十六烷基三甲基溴化铵(CTAB)改性石墨为导电填料,成功制备了一种新型的具有高导电性能的复合氟碳导电防腐杂化涂层材料。采用傅里叶变换红外光谱仪(FTIR)、扫描电镜(SEM)和X射线光电子能谱仪(XPS)表征改性前后石墨的结构以及涂层表面的微观形貌,根据国标测定涂层体积电阻率,并深入探讨涂层的导电机理。实验结果表明:CTAB与石墨以范德华力结合,增强了石墨在氟碳树脂中的分散性能;石墨的加入,增强了氟碳涂层的导电及耐热性能,完全满足接地网防护涂层的性能要求。     

HGAFS法代替GFAAS法测定水中的硒

用氢化物发生—原子荧光分析技术(HGAFS)和石墨炉原子吸收分光光度法(GFAAS)对水样中硒的测定进行了多方面的比较。通过一系列实验，设定了最佳仪器测量条件，并从其线性范围、最低检出限、精密度、准确度、回收率等方面进行对比实验。结果表明：HGAFS比GFAAS检出限低、精密性好、回收效果好、基体干扰少，且快速方便，完全可代替GB／T 15505—1995的GFAAS法，具有很好的可行性和适用性。     

马来酸酐接枝聚乙烯/石墨导电纳米复合材料的研究

用溶液插层法制备了马来酸酐接枝聚乙烯(MGPE)/膨胀石墨(EG)导电纳米复合材料,以熔体混合法作对照,通过电导率测试和X射线衍射、透射电镜、扫描电镜和光学显微分析,研究了复合材料的制备方法-形态结构-导电性能关系和导电通路形成机理。溶液插层法复合材料的逾渗阈值(1.65%体积)仅约为熔体混合法复合材料(3.03%体积)的一半。上述复合材料的导电行为和差异可用统计逾渗理论结合材料的形态结构特征来说明。     

聚苯酯／石墨／聚甲醛复合材料的力学性能

用转矩流变仪共混-模压成型方法制备了聚苯酯/石墨/聚甲醛复合材料，并对其力学性能（拉伸强度，弯曲强度，冲击强度和压缩强度）进行了研究。结果表明，聚苯酯的加入，使聚苯酯/石墨/聚甲醛复合材料的压缩强度提高，拉伸强度，弯曲强度和冲击强度有所降低，但并不防碍其作为结构零件使用；当聚苯酯含量为20%左右时，复合材料具有较为理想的综合力学性能。     

高密度聚乙烯／石墨PTC导电复合材料的研究

以高密度聚乙烯（PE—HD）为基体材料，选用四种不同粒径的石墨作为导电填充物探讨石墨粒径对复合体系PTC效应的影响，研究了石墨用量、增塑剂添加量和成核剂添加量对高密度聚乙烯佰墨复合体系电学性能及力学性能的影响。结果表明：选用50μm的石墨颗粒作为导电添加剂可以得到具有明显PTC强度的复合材料；正交实验最优化配比为高密度聚乙烯100g，石墨60g，邻苯二甲酸二辛酯25g，滑石粉12g；制备的复合材料弯曲强度为3．5MPa，PTC强度为6．4，与PE-HD／石墨复合材料相比弯曲强度减少了2／3，脆性明显下降，同时保持了较高的PTC强度，具有良好的综合性能。     

膨胀石墨膨胀机理的研究

在进行石墨膨胀实验的过程中，发现压片后的膨胀石墨不能再次膨胀很大倍数，通过XRD研究得出，膨胀石墨仍具有石墨的结构，并且还发现鳞片石墨中灰分的含量越少膨胀体积越大，这些实验结果证明传统的膨胀机理不完善，由此推断出一个新的膨胀机理，石墨的膨胀不仅发生在层间，还发生在鳞片石墨灰分挥发后留下的空位，并对这一结论作了论证。     

日本石墨换热器的发展及其现状

介绍了日本石墨换热器的发展概况，分析了研究了日本制造石墨换热器所用的材料，性能及应用情况，指出了日本近年来石墨换热器的发展趋势。     

Directional control of physico-chemical and mechanical properties of epoxide composites by the addition of graphite-graphene structures

ABSTRACT

As a result of the research, the possibility of directional control of the operational properties of epoxy composites by the use of small additives of thermally expanded graphite-graphene structures has been proved, providing the bending failure stress increases by 32% and the bending elastic modulus increases by 44%, the compression strength increases by 49%, the tensile strength increases by 74% and the tensile elastic modulus increases by 34%, impact resilience increases by 78%. The addition of thermally expanded graphite increases thermal, fire and heat resistance as well as the coefficient of heat-conducting epoxy composite.     

Compatibility of quaternary ammonium-based ionic liquid electrolytes with electrodes in lithium ion batteries

Electrochemical intercalation/deintercalation behavior of lithium into/from electrodes of lithium ion batteries was comparatively investigated in 1 mol/L LiClO₄ ethylene carbonate-diethyl carbonate (EC-DEC) electrolyte and a quaternary ammonium-based ionic liquid electrolyte. The natural graphite anode exhibited satisfactory electrochemical performance in the ionic liquid electrolyte containing 20 vol.% chloroethylenene carbonate (Cl-EC). This is attributed to the mild reduction of solvated Cl-EC molecules at the graphite/ionic electrolyte interface resulting in the formation of a thin and homogenous SEI on the graphite surface. However, rate capability of the graphite anode is poor due to the higher interfacial resistance than that obtained in 1 mol/L LiClO₄/EC-DEC organic electrolyte. Spinel LiMn₂O₄ cathode was also electrochemically cycled in the ionic electrolyte showing satisfactory capacity and reversibility. The ionic electrolyte system is thus promising for 4 V lithium ion batteries based on the concept of “greenness and safety”.     

Magnetic carbon: Explicit evidence of ferromagnetism induced by proton irradiation

The recently found ferromagnetic signals in pure graphite and in polymerised fullerenes are received mainly with scepticism by most of the scientific community. Actually, before those results were published, there were already several reports claiming an unusually large magnetization in pyrolytic carbon and oxidised fullerenes, without attracting the attention of the community. This scepticism may be well founded since not always a careful and systematic impurity study was provided to quantify the influence of ferromagnetic impurities. In this article and after a brief review of the existing data on magnetic carbon, we present and discuss recently obtained results on the ferromagnetism (or ferrimagnetism) induced by proton irradiation on pure pyrolytic graphite, which strengthen the importance of hydrogen in the formation of the magnetic ordering. The overall results indicate that room-temperature ferromagnetism in carbon-based structures containing only p- and s-electrons is a reality.