石墨层间化合物的制取及其应用

石墨层间化合物是一种新型的纳米材料,具有广泛的应用背景。本文介绍了石墨层间化合物的原理以及种类,几种制备方法：双室法、化学氧化法、电化学法、溶剂法、混合法、加压法等,并比较了他们各自的优缺点及应用现状。     

自吸背景校正石墨炉原子吸收法测定全血中的铅

铅是一种蓄积性的有毒物质,过量铅的摄入严重影响人的身心健康。血铅是作为职业性铅中毒和职业性健康检查的必检项目。文章用专用试剂直接稀释样品,无需在标准溶液中加入健康人血做基体匹配,自吸背景校正石墨炉原子吸收法直接测定全血中的铅,方法的精密度为2.34%～5.45%,回收率为107%,检出限为0.98μg/L,获得了满意的...     

Methylene blue adsorption onto an eco-friendly modified polyacrylamide/graphite composites: Investigation of kinetics,equilibrium, and thermodynamic studies

ABSTRACT

Batch adsorption system using eco-friendly glucose and glucosamine grafted polyacrylamide/graphite composites were investigated to eliminate methylene blue (MB) dye from aqueous solution. The effect adsorption parameters reveal that pseudo-second order and Langmuir model exhibited good correlation with the adsorption kinetic and isotherm data for pollutant, respectively. Furthermore, an increase in pH from 2 to 11 was accompanied by an approximately fourfold increase in the amount of dye adsorbed. The maximum removal efficiency of MB was 96.23% under optimum conditions with equilibrium time of 40 min. The thermodynamic data supported its spontaneous and endothermic property of adsorption process. A possible adsorption mechanism has been proposed, where H-bonding and electrostatic interactions dominated the adsorption of dye.     

石墨炉原子吸收光谱法测定柑橘皮中铅

采用加入基体改进剂-石墨炉原予吸收光谱法测定柑橘皮样品中的痕量铅。应用塞曼效应消除背景干扰,以20g／L的磷酸二氢铵（NIGH2P04）为基体改进剂,灰化温度为500℃,原子化温度为1900℃。试样消解分别采用了湿法消化法和下法灰化法。铅的质鬣浓度在0-110μg/L范围内与其吸光度呈线性关系,湿法消化法和干法灰化法的检出限（3s）分别为12．26μg／kg和3．803μ／kg。应用此建立的石墨炉原予吸收光谱法分析了几种柑橘皮试样中铅,方法快速简便、结果比较准确。     

高导热系数聚丙烯复合材料的制备及研究

将氧化镁、氧化铝和石墨分别与聚丙烯熔融共混制备导热复合材料,考察了填料种类、基体黏度和增容改性对复合材料导热系数(λ)的影响。结果表明:增加填料含量能逐渐提高λ,且填料的λ直接决定了复合材料的λ;基体黏度越高,复合材料导热性能提高越显著;对氧化镁和氧化铝进行表面改性同时加入增容剂,可以明显减少填料的团聚,形成更多的有效网链,能有效提高复合材料的导热性能。探究了将氧化镁和氧化铝分别与石墨复配来制备高λ的复合材料,发现少量石墨与无机填料复配可以大幅提高复合材料的λ,当聚丙烯/增容剂/氧化镁/石墨质量比为30/10/50/10时,λ达到1.267 W/(m K),比不添加石墨时提高了50%;而对于氧化铝和石墨的复配体系,λ为0.622 W/(m K),相比于未添加石墨时增加了60%。     

高碳石墨生产中废酸制备聚合氯化铝铁的研究

研究了利用“碱熔-水洗-酸浸”法提纯石墨过程中含Fe”废酸制备聚合氯化铝铁(PAFC)的工艺条件,结果表明直接用回收酸制备高效混凝剂PAFC切实可行,所制备的PAFC具有适用范围宽,混凝效果优的特点。     

Improved oxidation resistance of expanded graphite through nano SiC coating

Expanded graphite with nano SiC and amorphous SiC_xO_y coating was successfully prepared through pyrolysing silane coupling agent (SCA), where the grafting of SCA dominated the final products. The results show that mainly amorphous SiC_xO_y coating covers expanded graphite at 1000 °C, regardless of the SCA concentration. In comparison, nano SiC coating can be synthesized at 1200 °C depending on the good dispersion of SCA (with a SCA concentration of 50 vol%). The formed SiC coating contributes to much higher peak oxidation temperature (812.1 °C) than 678.0 °C of the pure expanded graphite. Meanwhile, the oxidation activation energies of expanded graphite are remarkably improved from 149.15 kJ/mol to 176.16 kJ/mol (based on Kissinger method), attributing to the derived nano SiC and SiC_xO_y coating.     

A New Single Fiber/Resin Interface Test for Highly Cross-Linked Resin Systems

A new single fiber/resin interface test technique has been developed to test fibers in highly cross-linked resins that were difficult to characterize before. The new approach was based on the fracture mechanics considerations to allow brittle thin resin film with embedded single fiber to undergo large strain elongation. This was achieved by sandwiching the resin between high elongation epoxy doublers. Several systems with graphite fibers in highly cross-linked epoxy and bismaleimide resins were successfully characterized for strains up to 6%. Because of the thin resin film used, even matrix materials with limited transparency in bulk form could easily be tested. At sufficiently high strains, the fiber/resin systems showed interface-related behavior consistent with their edge delamination performance previously studied.     

石墨炉原子吸收光谱法检测烟用接嘴胶中铬的含量

为了建立石墨炉原子吸收光谱法检测烟用接嘴胶中铬含量的方法,研究了待测接嘴胶的用量、灰化温度、原子化温度及基体改进剂对检测的影响.确定的优化检测条件为：烟用接嘴胶用量为0.3000 9,铬的灰化温度、原子化温度、基体改进剂分别为800℃,2300℃和1.00 g/L氯化钯.在优选的实验条件下检出限分别为0.245 μg/kg,相对标准偏差分别为1.26％,回收率范围分别在93.8～106.8％之间.本方法检出限低,重复性好,回收率高,简单方便.     

PP/POE/GNP导电复合材料的制备与性能研究

用油酸钠/乙醇溶液、邻二氯苯、N-甲基吡咯烷酮对膨胀石墨进行表面处理和分散改性并制备了纳米石墨微片(GNP),研究了其效果,确定了油酸钠/乙醇溶液作为分散介质和表面改性剂。将由该处理剂制得的GNP以不同添加量添加到聚丙烯/聚烯烃弹性体共混树脂(PP/POE)中,制得PP/POE/GNP复合材料。测试表明,GNP在基体中分散均匀,大部分达到纳米尺寸,与基体结合良好,复合材料的室温渗滤阈值为9%左右(对应GNP质量份数为10份),GNP质量份数超过10份之后复合材料成为半导体,最低体积电阻率为3.6×107Ω.cm。当GNP质量份数为20份时,复合材料仍然保持较佳力学性能,材料破坏方式为脆性断裂。