聚苯胺/碳复合物的合成及其电化学性能研究

采用化学法合成了聚苯胺/活性炭(PANi/C)和聚苯胺/石墨(PANi/G)复合材料,并研究了其电化学性能.在合成过程中,加入石墨或活性炭均可提高PANi的产率,尤其加入活性炭.所获得的PANi/C、PANi/G复合物的电导率高于聚苯胺与活性炭(PANi+C)、聚苯胺与石墨(PANi+G)混合物及PANi的电导率,其中加入石墨的PANi/G复合物电导率明显增大.以PANi、PANi/G和PANi/C作为Zn-PANi二次电池阴极材料,其放电比容量分别为74.1 mAhg-1、101.3 mAhg-1和118.7mAhg-1,电池库伦效率达90-100%.     

磺基水杨酸掺杂聚苯胺/石墨复合粉体的研究

研究了磺基水杨酸(SSA)对PANi/EP的机械力化学掺杂作用,通过电导率测定、SEM观察和FT-IR研究了体系的导电性能和掺杂机理.结果表明,SSA与PANi/EP粉体按照一定比例共碾磨,在复合粉体与SSA质量比为2.5时,共碾磨90 min电导率达到最高值0.438 S/cm,105 ℃退火2 h,测试其电导率为2.762 S/cm,提高了约5倍,但仍低于盐酸掺杂样品.可见高熔点有机酸对聚苯胺的固相机械力化学掺杂,避免了溶剂体系对环境的污染,是一种低成本绿色工艺.SEM表明,SSA掺杂PANi/EP复合粉体具有疏松多孔不规则形貌特征,粒径大小在0.5 μm～1 μm;FT-IR比较发现,SSA的特征峰3113 cm-1消失,1667 cm-1减弱并发生左移,1068 cm-1和1582 cm-1合并成一个1582 cm-1峰.表明SSA与PANi/EP发生了化学反应,即SSA与PANi/EP发生了掺杂.     

聚苯胺/氧化石墨的合成及其在DNA识别上的应用

采用层离/吸附和原位聚合相结合的方法合成了聚苯胺/氧化石墨复合材料（PAn/GO）.利用TEM、AFM、XRD、FTIR等方法对PAn/GO的结构和电化学性能进行了研究.以PAn/GO修饰炭糊电极为工作电极,采用方波伏安法（SWV）检测了单链小牛胸腺DNA（CTssDNA）和双链小牛胸腺DNA（CTdsDNA）.研究结果表明：PAn/GO为当量直径约60 nm～70 nm的扁球状纳米颗粒,这些纳米颗粒呈链状聚集,并具有电化学活性;聚苯胺（PAn）以双层平行排列的方式嵌入氧化石墨层间和包覆在氧化石墨表面两种形式与氧化石墨结合;PAn/GO修饰炭糊电极识别单链小牛胸腺DNA（CTssDNA）和双链小牛胸腺DNA（CTdsDNA）时的峰电位分别为90.99 mV和18.00 mV.     

界面聚合法制备管状聚苯胺/聚苯胺包覆镍纳米复合材料及其电磁特性

采用工艺简单的界面聚合法制备了管状聚苯胺(PANi)及管状聚苯胺/聚苯胺包覆镍纳米粒子(PANi/PANi(Ni))复合材料。上层油相采用正己烷,下层水相采用稀盐酸溶液,将两相混合并添加镍纳米颗粒,在两相的界面处发生化学复合反应。通过FT-IR、XRD、TEM分析表征表明,生成了管状聚苯胺,形状均一,直径大约在100nm,并且存在着部分的结晶。聚苯胺很好地包覆了纳米镍粉,实现了管状聚苯胺及聚苯胺包覆纳米镍粉的多种物质及形态的复合,对其制备工艺及微波频段的电磁特性进行了研究。     

细鳞片与大鳞片膨胀石墨微观结构的比较研究

用混酸（浓硫酸、浓消酸）、强氧化剂处理天然鳞片[大鳞片（-60～＋80目），细鳞片（-140～＋160目）]石墨，制得可膨胀石墨，再经高温膨胀得膨胀石墨。采用SEM对两各种膨胀石墨的形貌进行观察分析，发现不同粒度的石墨获得的膨胀石墨其微观孔结构的特征基本相同，但尺寸上存在较大的差异。采用XRD对原料石墨、可膨胀石墨和膨胀石墨的结构作了分析，通过层间距变化、衍射峰出现与消失的情况，判断出不同鳞片大小的石墨在氧化、膨胀过程中发生了相同的变化，从而证明了不同鳞片大小的石墨的膨胀机理是相同的。     

原位膨胀法制备PMMA/EG复合材料及其导电和流变性能的研究

使用低温可膨胀石墨,通过"原位膨胀-机械剥离"的方法制备了PMMA/EG复合材料,研究了可膨胀石墨含量对其电导率的影响。电导率、SEM、动态流变等测试表明膨胀后的石墨片层在树脂基体中分散良好;从10~20 phr开始,石墨鳞片相互接触形成网络结构显著地提高电导率,最高达12个数量级。采用原位膨胀法可以制备逾渗阈值较小的导电复合材料,填充少量低温可膨胀石墨就可以大幅度提高PMMA电导率。     

高导电聚苯胺/纳米石墨微片复合材料的结构与性能

以天然可膨胀石墨(GN)为原材料,采用酸及快速热处理制备了膨胀石墨(EG),再将膨胀石墨置于超声波中制得了纳米石墨微片(NanoG),最后采用原位聚合法制备了聚苯胺/纳米石墨微片(PANI/NanoG)导电复合物。扫描电镜(SEM)显示纳米石墨微片长径为0.8μm～20μm,厚度为30nm～90nm。聚苯胺均匀覆盖在纳米石墨微片表面;透射电镜(TEM)揭示了纳米石墨微片的片层分散在复合物中并形成了导电网络;电性能测试表明,当纳米石墨微片含量为0.5%(质量分数,下同)时,复合物电导率达到107.3S/cm,其渗滤阈值达到0.1%,纳米石墨微片独特的结构(宽度/厚度的高比值)及在聚苯胺中的分散造就了复合物良好的导电性能。     

聚甲基丙烯酸甲酯/膨胀石墨纳米导电复合材料的制备与表征

通过原位插层聚合制备了聚甲基丙烯酸甲酯/膨胀石墨纳米导电复合材料,其室温导电渗滤阈值约为3%(质量分数),当膨胀石墨的质量分数为8%时,室温电导率可高达60 S/cm。通过TEM、SEM观察了复合材料的形貌,用DSC测定其热力学性能并探讨了不同外加电压对PMM A/膨胀石墨纳米导电复合材料体积电导率的影响,同时研究了复合材料的拉伸强度。     

膨胀石墨/酚醛树脂-聚乙烯醇缩丁醛复合双极板的制备与性能

采用聚乙烯醇缩丁醛（PVB）对酚醛树脂（PF）进行改性,并以膨胀石墨为第一导电填料,用模压成型法制备了新型质子交换膜燃料电池用膨胀石墨/PF-PVB复合材料双极板。研究了PVB与PF质量比、改性树脂含量及炭黑的添加对膨胀石墨/PF-PVB复合材料双极板电导率、抗弯强度等性能的影响。结果表明,当改性树脂质量分数固定为30wt%时,膨胀石墨/PF-PVB复合材料双极板在PVB：PF=0.5时表现出最佳的电导率及抗弯强度,分别为192.3 S/cm、47.25 MPa,与不添加PVB的膨胀石墨/PF复合材料双极板相比,平面内电导率和抗弯强度分别提高了12.3%、14.2%。在PVB含量固定的条件下（PVB：PF=0.5）,当改性树脂的质量分数由25wt%增加至45wt%时,膨胀石墨/PF-PVB复合材料双极板的电导率下降,而抗弯强度增加。进一步添加炭黑提高膨胀石墨/PF-PVB复合材料双极板的导电性能,当改性树脂质量分数固定为45wt%时,炭黑添加量为4wt%的试样表现出最佳的平面电导率和面比电阻,分别为137 S/cm、14.4 mΩ·cm²。     

石墨微球的制备及化学修饰

采用化学气相沉积（CVD）法以脱油沥青（deoiled asphalt，DOA）为碳源制备出碳微球，对碳微球进行了真空热处理，运用硬脂酸对石墨微球进行表面修饰，并研究了硬脂酸修饰后石墨微球作为润滑油添加剂的分散性和稳定性。采用X射线衍射（XRD），场发射扫描电镜（SEM），高分辨透射电镜（HRTEM）分析了石墨微球的晶体结构和形貌，结果表明所制备的碳微球纯度很高，粒径均匀（500nm），真空热处理后显著提高了碳微球的石墨化程度，使碳微球转变为石墨微球。傅立叶红外（FT—IR）实验证明，通过酯化反应石墨微球能够被硬脂酸包覆；显著提高了石墨微球在润滑油中的分散性和稳定性。     

可溶性聚苯胺/聚乙烯醇掺杂氧化石墨烯复合材料的制备

通过加入十二烷基苯磺酸钠(SDBS)制备了可溶性的聚苯胺/聚乙烯醇掺杂氧化石墨烯导电复合材料。通过XRD、SEM、TEM、FT-IR、TGA、CV对合成的复合材料进行了表征和分析,结果表明聚苯胺/聚乙烯醇能够插入到氧化石墨烯的层间和包裹在氧化石墨烯的表面形成复合物。用十二烷基苯磺酸钠掺杂的聚苯胺/聚乙烯醇/氧化石墨烯材料具有很好的溶解性和导电性能,将复合物进行还原和再次用酸掺杂之后,发现复合材料的导电性得到进一步提升。     

Effect of different carbon fillers and dopant acids on electrical properties of polyaniline nanocomposites

Electrically conducting nanocomposites of polyaniline (PANI) with carbon-based fillers have evinced considerable interest for various applications such as rechargeable batteries, microelectronics, sensors, electrochromic displays and light-emitting and photovoltaic devices. The nature of both the carbon filler and the dopant acid can significantly influence the conductivity of these nanocomposites. This paper describes the effects of carbon fillers like carbon black (CB), graphite (GR) and muti-walled carbon nanotubes (MWCNT) and of dopant acids like methane sulfonic acid (MSA), camphor sulfonic acid (CSA), hydrochloric acid (HCl) and sulfuric acid (H₂SO₄) on the electrical conductivity of PANI. The morphological, structural and electrical properties of neat PANI and carbon–PANI nanocomposites were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT–IR), UV–Vis spectroscopy and the four-point probe technique, respectively. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies were also conducted for different PANI composites. The results show that PANI and carbon–PANI composites with organic acid dopants show good thermal stability and higher electrical conductivity than those with inorganic acid dopants. Also, carbon–PANI composites generally show higher electrical conductivity than neat PANI, with highest conductivities for PANI–CNT composites. Thus, in essence, PANI–CNT composites prepared using organic acid dopants are most suitable for conducting applications.     

Preparation of low-density polyethylene/low-temperature expandable graphite composites with high thermal conductivity by an in situ expansion melt blending process

A facile strategy with the advantages of low cost and ease of mass production was presented to prepare low-density polyethylene (LDPE)/low-temperature expandable graphite (LTEG) composites with relatively high thermal conductivity by an in situ expansion melt blending process. LTEGs were expanded and delaminated into graphite multi-layers and graphite nanoplatelets during processing which synergistically created more thermo-conducting paths in the composites and hence led to great improvements in thermal conductivity. Thermal conductivity of the composite with 60 wt% of LTEG loading was increased by 23 times as compared to the pure LDPE, increasing from 0.47 to 11.28 W/mK. The incorporation of LTEG decreased the melting temperature and the degree of crystallinity of LDPE. Percolation threshold of both the electrical conductivity and rheological measurements was observed at about 8 vol% of LTEG loading. Moreover, the LDPE/LTEG composites showed better thermal stability compared to the pure LDPE.     

Influence of thermal treatment on the structure and electrical conductivity of thermally expanded graphite

Thermally expanded graphite (TEG) is a promising filler beneficial to electrically conductive materials due to its high electrical conductivity, low density, and cost. In this work, the electrically conductive TEG was prepared by thermal treatment of the expandable graphite in the range of temperatures from 400 to 800 °C in air. Effects of the temperature treatment on the morphology and chemical structure of TEG were thoroughly characterized. Thermal treatment of the expandable graphite resulted in thermally expanded graphite formation with up to 6 times higher electrical conductivity than the precursor. Optimal conditions of thermal treatment were established at 600 °C providing material with the highest electrical conductivity, high expansion volume, and a well-ordered and defect-less structure.     

Thermoelectric properties of graphene nanosheets-modified polyaniline hybrid nanocomposites by an in situ chemical polymerization

A hybrid material of polyaniline protonated with hydrochloric acid and conductive graphene nanosheets (PANi/GNs) has been prepared by an in situ chemical polymerization method. The interactions between PANi and GNs in the hybrid composites are investigated by utilizing XRD, FT-IR, UV–vis and Raman. It is found that the PANi are adsorbed on the surface of the GNs, and the morphology of PANi transforms from twist structure to extended structure after the GNs are introduced. The thermoelectric (TE) properties of PANi/GNs composites have been investigated in the range from 323 K to 453 K. The electrical conductivity and the Seebeck coefficient of PANi/GNs composites are obviously higher than those of the PANi, while the thermal conductivity of the composites still keeps relatively low values even with high GNs content, resulting in the increase in dimensionless figure of merit (ZT). A highest ZT value of 1.95 × 10⁻³ has been obtained for the composite containing 30 wt % GNs at 453 K, which is about 70 times higher than that obtained from the PANi.     

膨胀石墨复合材料的电磁特性及其3mm、8mm波动态衰减性能研究

通过高温下膨化二茂铁与可膨胀石墨混合物的方法, 制得附着铁氧化物的膨胀石墨复合材料. 铁氧化物的主要成分为Fe₂O₃、Fe₃O₄, 随着铁氧化物含量的增加, 其平均电导率呈下降趋势, 而磁化强度逐渐增强, 复合材料呈亚铁磁性. 在不影响膨胀石墨电损耗吸收的同时, 复合材料增加了磁损耗吸收, 其3mm、8mm波动态衰减效果明显优于单纯的膨胀石墨. 二茂铁和可膨胀石墨的质量比为2～3:5时, 3mm、 8mm波动态衰减能力最强.     

PANI/SnO2导电复合材料的制备及光催化吸附性能

采用水热合成法制备了类球状二氧化锡纳米粉体,再经原位聚合工艺制备聚苯胺(PANI)/SnO2纳米复合材料。利用红外光谱(IR)、X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)表征了材料的结构和形貌,用四探针测试了材料的电导率,考察了反应物配比对复合材料导电性及光催化吸附性能的影响。结果表明,PANI与SnO2之间存在着化学键的结合,形成交联的孔状结构。复合材料兼具良好的导电性和较高的光催化吸附性能,掺杂30%SnO2纳米粒子时,复合材料的电导率为3.57 S/cm,相比于掺杂态聚苯胺提高了将近十倍,对萘酚绿B的吸附降解率达98%,且循环使用率较高(80%±6%)。