Regenerated cellulose nanocomposites reinforced with exfoliated graphite nanosheets using BMIMCL ionic liquid

Green nanocomposites of regenerated cellulose/exfoliated graphite nanosheets films with low nanofiller loadings were prepared using environmentally benign 1-butyl-3-methylimidazolium chloride (BMIMCl) ionic liquid. X-ray diffraction revealed well developed intercalated nanocomposites. The tensile strength and Young's modulus of the prepared nanocomposites were increased by 97.5% and 172% respectively when 0.75 wt.% and 1 wt.% exfoliated graphite nanosheets were added. The results were validated using the Halpin–Tsai model. The exfoliated graphite nanosheets were unidirectionally aligned in the regenerated cellulose parallel to the surface of the nanocomposites as revealed by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Also, the TEM and FESEM revealed uniform dispersion of the exfoliated graphite nanosheets and good interaction between the nanofillers and the matrix. The addition of the exfoliated graphite nanosheets enhanced the thermal stability and reduced the water absorption and diffusivity of the nanocomposites.     

Carbon nanotube–polyaniline composites

The last decade has seen a growing interest in hybrid electrically conducting nanocomposites. This article aims to provide a detailed overview of the present status of research in carbon nanotube–polyaniline (CNT/PANI) composites, from processing to structural and property evaluations. CNT/PANI are synthesized by electrochemical and chemical processing. When chemical methods are used, the main challenge is to obtain processable CNT/PANI in the emeraldine salt (ES) form composites. Stable dispersions of ES–CNT in organic media are prepared using the post doping method, inverse emulsion polymerization, or ex situ polymerizations. On the contrary, stable water dispersions of CNT/ES are prepared using hydrophilization of a preformed CNT/ES composite, direct synthesis of micelle–CNT hybrid templates, interfacial polymerization, covalent functionalization of CNT with a water soluble polymer, or using electrostatic interactions between two oppositely charged ES and CNT aqueous colloids. Moreover, the strategies for the synthesis of ternary CNT/PANI composites incorporating noble metal nanoparticles, metal oxide, or graphene sheets are also presented and analyzed in depth. Finally, we give a review of potential applications, including chemical sensors, capacitors, fuel cells and electronic devices.     

导热PE-LD复合材料的制备与性能研究

采用低密度聚乙烯(PE-LD)为基体材料,石墨、Al N为导热填充材料,通过双辊混炼、模压制备了导热复合材料,并对该复合材料的导热性能、力学性能、热行为进行了分析。结果表明,随着石墨或Al N含量的增加,PE-LD/石墨复合材料和PE-LD/Al N复合材料的热导率逐渐增大;PE-LD/石墨复合材料的热导率高于PE-LD/Al N复合材料的热导率。当石墨与Al N的总质量分数为50%、石墨与Al N的质量比为4∶1时,PE-LD/石墨/Al N复合材料的拉伸强度、弯曲强度均达到最大值,分别为12.8,17.15 MPa;此时PE-LD/石墨/Al N复合材料的热导率达到最大值,为0.618 W/(m·K),略低于添加质量分数50%的石墨时的PE-LD/石墨复合材料的热导率[0.634 W/(m·K)];当石墨与Al N质量比为1∶4时,PE-LD/石墨/Al N复合材料的热导率为0.488 W/(m·K),高于只添加质量分数50%Al N的PE-LD/Al N复合材料的热导率[0.410 W/(m·K)]。当石墨和Al N总质量分数为50%时,随着Al N含量的增加,PE-LD的结晶度增大。     

无机盐离子对CoFe_2O_4/GO催化PMS氧化降解酸性橙Ⅱ的影响

考察了四种无机盐离子H2PO4-、HCO3-、NO3-、Cl-对CoFe2O4/GO催化单过硫氢钾(PMS)降解酸性橙II的影响进行了研究。实验结果表明:随着无机盐离子浓度的增加,H2PO4-起到促进作用,HCO3-起到先促进后抑制作用,Cl-和NO3-起到抑制作用。     

石墨粉对低锌含量水性环氧富锌漆阴极保护性能的影响

配制了颜料体积浓度(PVC)与临界颜料体积浓度(CPVC)之比为0.9的低锌含量水性环氧富锌漆,加入占锌粉质量1%、2%和3%的石墨粉,研究了石墨粉对水性环氧富锌涂层阴极保护性能的影响。涂层的阴极保护性能评价采用传统的开路电位(OCP)测试法与自行开发设计的恒电流溶解法。OCP测试结果表明,添加石墨后的涂层有更长的阴极保护时间,石墨粉添加量越大,阴极保护时间越长。恒电流溶解法测试结果表明,加入石墨粉之后涂层的活性溶解时间变长,石墨粉添加量越高,活性溶解时间越长。导电胶和涂层电极在3.5%NaCl溶液中的电化学阻抗谱测试结果表明,随着石墨粉含量的增加,涂层阻抗降低,阴极保护作用增强。     

GF/PVDF导电复合材料的PTC行为

以石墨纤维(GF)、乙炔炭黑(CB)为导电填料,聚偏氟乙烯(PVDF)为基体,通过熔融共混方法分别制备GF/PVDF、CB/PVDF导电复合材料。讨论了导电填料形状、含量对复合材料正温度系数效应(PTC)的影响。并通过实验现象分析认为具有长径比结构的GF是导电复合材料负温度系数效应(NTC)减弱的原因,结合差示扫描量热分析(DSC)证明PTC效应与聚合物结晶熔融有直接关系。     

模温和热处理对PET/石墨复合材料导热性能的影响

从影响PET结晶度的角度出发,研究了模具温度和热处理工艺对复合材料热导率的影响,并通过DSC测试对实验结果进行了分析。结果表明:在一定温度范围内,模温升高有利于复合材料中PET结晶的完善和结晶度的提高。选用适当的温度对共混体系进行热处理可使共混材料中的热应力得到松弛,能促进聚合物分子链运动重排,共混物中PET的结晶完善、结晶度提高,提升复合材料的导热性能。     

炭/石墨材料的成型工艺综述

由于炭/石墨材料在冶金、太阳能、核能、原子能、半导体、航空航天等领域的广泛应用,本文针对当前国内炭/石墨材料的成型方式,主要探讨挤压成型、模压成型和等静压成型,以及它们的技术特点.     

石墨炉原子吸收光谱法测定银柴胡中铅含量

实验使用微波消解技术对银柴胡进行前处理,利用石墨炉原子吸收光谱法测定银柴胡中的铅含量。优化了仪器条件及实验条件,利用标准曲线法测定样品中铅含量,方法检测限为0.091μg·L-1。结果表明,本法能够准确、快速测定银柴胡中铅含量。微波消解法空白值低,避免了铅的损失,提高了分析的准确度和精密度。     

副产蒸汽氯化氢石墨合成炉应用总结

介绍了副产蒸汽氯化氢合成炉工艺流程、设备特点、运行情况及副产蒸汽的效益。