湿敏性碳纳米管在聚氯乙烯抗静电复合材料中的研究与应用

利用碳纳米管(CNTs)与十六烷基三甲基溴化铵(CTAB)的吸附作用,制得具有湿敏特性的CNTs,并通过红外光谱分析和热失重分析确定其组成;将其作为抗静电剂加入到聚氯乙烯(PVC)中,通过模拟潮湿环境研究其湿敏特性对PVC/CNTs复合材料体积电导率的影响规律。结果表明,CNTs的有机化改性可降低其在复合材料中的逾渗阈值;当CNTs添加量为4%(质量分数,下同)时,经过潮湿处理的PVC复合材料的电导率可升高4个数量级。     

PPy/Ni/NanoG复合材料的制备及导电性能研究

以聚吡咯（PPy）为基体,FeCl3作为氧化剂,十二烷基苯磺酸钠（DBSNa）作为掺杂剂,表面镀有金属镍(Ni)膜的纳米石墨微片（NanoG）作为二维层状纳米填料,通过原位聚合法制备了PPy/Ni/NanoG导电复合材料,并对其结构和导电性能进行了表征。结果表明,PPy与Ni/NanoG的相容性较好,PPy聚合物均匀地包覆在Ni/NanoG片层表面和边缘;Ni/NanoG的二维受限空间的阻隔作用能够有效抑制PPy分子链的卷曲和交联,使PPy分子链共轭程度提高,π电子的离域性增加;循环伏安测试表明复合材料的峰面积大,峰电流高,导电能力强;复合材料的导电性能随Ni/NanoG含量的增加由8.2 S/cm提高到103.6 S/cm,Ni/NanoG的阈值为2 %（质量分数,下同）。     

聚吡咯/SiO2作导电助剂的水性环氧抗静电涂料的制备

以导电性聚吡咯/二氧化硅(PPy/SiO2)复合材料作导电助剂,与环氧树脂乳液混合,经聚酰胺X-650固化后,制备了电导率在10-9～10-4S·cm-1之间的水性环氧抗静电涂料.结果表明PPy/SiO2用量为环氧乳液的2%(质量分数,下同)时,环氧涂层的电导率可从10-16S·cm-1提高到1.2×10-9S·cm-1,而且PPy/SiO2用量低于8%时,涂层具有良好的综合性能,对玻璃和马口铁附着力为1级,耐冲击性大于50 cm,铅笔硬度H,耐水性和柔韧性优良.SEM观察结果表明PPy/SiO2在环氧涂层中具有良好的分散性,且与环氧基体结合比较紧密.     

聚酯/碳纳米管导电纤维结构与性能的研究

通过双螺杆挤出机制备聚酯／碳纳米管(PET／CNTs)导电复合材料,为保证CNTs在PET中分散均匀,同时加入了矿物偶联剂,经扫描电镜分析,加入相对CNTs质量分数为50％矿物偶联剂能帮助CNTs在PET基体中均匀分散。PET复合材料中加入质量分数约为2％的CNTs可以使其体积电阻率从1014下降到102数量级。采用复合纺丝获得了导电纤维,分别在PET织物和羊毛织物中,添加相对织物质量分数为25％,3％的PET／CNTs导电纤维,可使相应织物具有优良的抗静电效果。     

油酸功能化石墨烯的制备及其在聚乙烯中的应用

以氧化石墨烯为原料,将油酸分子连接在石墨烯的表面,得到油酸功能化石墨烯,并通过溶液法将其与聚乙烯基体共混获得聚乙烯/功能化石墨烯复合材料,研究了复合材料的导电性能。结果表明,在低石墨烯含量下可大幅提高聚乙烯的导电性能。当油酸功能化石墨烯质量分数为8%时,复合材料的电导率达1 S/m;当油酸功能化石墨烯质量分数为10%时,复合材料的电导率达3 S/m。聚乙烯/功能化石墨烯复合材料在电缆屏蔽、电磁屏蔽和抗静电领域具有应用价值。     

改性石墨烯/丁腈橡胶纳米复合材料的制备及性能研究

通过简单的回流氧化石墨烯(GO)和二乙基甲苯二胺(E-100)成功实现氧化石墨烯的原位功能化还原,制备了导电及表面修饰的氧化石墨烯(GO-E100),其电导率由GO的1. 0×10-7S/m提高到1 S/m。此外,制备的GO-E100有效地增强了以丁腈橡胶(NBR)为基体的柔性复合材料的力学性能和导电性能。当GO-E100在复合材料中的质量分数为4. 2%时,复合材料电导率达到3. 2×10-12S/m,比纯NBR增加了3个数量级,同时拉伸强度提高了18. 6%;当GO-E100在复合材料中的质量分数为6. 8%时,其拉伸强度提高了12%,耐油性稍有改善,复合材料电导率达到5. 6×10-8S/m,比纯的NBR增加了7个数量级,基本满足抗静电要求。     

着色抗静电PVC糊的性能

以聚氯乙烯(PVC)糊为基体树脂,采用导电云母粉为抗静电剂,并添加颜料制备了着色抗静电PVC糊。探索了导电云母粉用量对PVC糊抗静电性能的影响,不同颜料的添加量对PVC糊着色性能的影响,并着重研究了环保型颜料有机红144对PVC糊的着色性能、导电性能、微观分散性、力学性能的影响。结果表明:导电云母粉用量为15.0 phr时,改性PVC糊的抗静电性能较好;当有机红144质量分数为1.2%时,着色抗静电PVC糊的着色性能较优,表面电阻率不随颜料含量变化而变化,力学性能略有降低。     

碳纳米管/碳纤维增强聚苯硫醚复合材料研究

研究了采用碳纤维(CF)和碳纳米管(CNTs)增强聚苯硫醚(PPS)的力学性能和导电性能。实验分别采用CF和CNTs为添加剂,通过球磨混合后在平板硫化机上进行模压成型,制备出CF/PPS、CNTs/PPS和CNTs/CFPPS/复合材料。采用万能试验机测试复合材料的拉伸性能;采用数字式四探针测试仪测试材料的电导率。实验研究了CF和CNTs含量对其复合材料的导电性能和力学性能的影响,并进一步研究同时添加CF和CNTs对复合材料增强作用。通过分析复合材料的导电性能和力学性能,分别得出CF含量为20%、CNTs含量为15%时复合材料的力学性能和导电性能较理想。采用CF和CNTs同时增强PPS时,当CF添加16%、CNTs添加4%时,CNTs/CF/PPS复合材料性能较好。此外,对CF和CNTs增强机制进行初步讨论。     

聚氨酯/碳纳米管复合材料力学及电性能研究

利用超声分散和原位聚合的方法制备了聚氨酯／碳纳米管((PUR／CNTs)复合材料,观察了该复合材料的微观结构,探讨了CNTs含量对复合材料力学性能和电性能的影响。结果表明,CNTs在基体中获得了较好的分散,当CNTs质量分数为2％时复合材料的力学性能得到全面提高,与PUR相比,拉伸强度提高11．6％,拉伸弹性模量提高11．3％,断裂伸长率提高10．4％;复合材料的导电性能得到明显的提高,在CNTs质量分数为0．5％时可用作抗静电材料。     

PLA/PPy复合材料的制备及表征

以吡咯(Py)为原料,通过原位聚合法合成聚吡咯(PPy)导电粒子,通过PPy粒子对聚乳酸(PLA)进行改性,制备PLA基导电复合材料,并对其形貌、力学性能及导电性能进行测试。结果表明:PPy可以与PLA基体呈现一种紧密结合的状态;PLA/PPy(5%)导电复合材料综合性能最佳,其拉伸强度为51.2 MPa、断裂伸长率为163.5%、电导率为4.12×10~(-5) S/cm。     

Electrical and mechanical properties of pre-localized polypyrrole/poly(vinyl chloride) conductive composites

A novel process for preparation of conductive polypyrrole/poly(vinyl chloride) (PPy/PVC) composites by pre-localization of an intrinsically conducting PPy phase in a PVC matrix has been developed. This process involves encapsulating PVC particles with a thin layer of PPy, and subsequently compacting this PPy-encapsulated PVC powder by compression molding. The current-voltage characteristics and electrical conductivity of the pre-localized PPy/PVC composites were determined. The change of the current-voltage characteristics from linear to nonlinear behavior with increasing PPy content in the composites is discussed in the view of the intermolecular hopping and tunneling of electrons. The tensile properties, dynamic mechanical behavior, and microhardness of the pre-localized PPy/PVC composites were studied as a function of PPy content. A percolation threshold of 0.3 wt% is achieved in the pre-localized PPy/PVC composites. This value is much lower than those of the conventional conductive composite materials containing a random distribution of PPy fillers. The samples with a PPy content of 1.6 wt% or above have high conductivity and still preserve reasonable mechanical properties.     

Fabrication of carbon nanotubes/polypyrrole/carbon nanotubes/melamine foam for supercapacitor

The carbon nanotubes (CNTs) have been loaded on the melamine foam (MF) to form the composite (CNTs/MF) by dip‐dry process, then polypyrrole (PPy) is coated on CNTs/MF (PPy/CNTs/MF) through chemical oxidation polymerization by using FeCl₃·6H₂O adsorbed on CNTs/MF as oxidant to polymerize the pyrrole vapor. Finally, CNTs are coated on the surface of PPy/CNTs/MF to increase the conductivity of the composite (CNTs/PPy/CNTs/MF) by dip‐dry process again. The composites have been characterized by X‐ray diffraction spectroscopy, scanning electron microscopy and electrochemical method. The results show that the structure of the composites has obvious influence on their capacitive properties. According to the galvanostatic charge/discharge test, the specific capacitance of CNTs/PPy/CNTs/MF is about 184 F g^?1 based on the total mass of the composite and 262 F g^?1 based on the mass of PPy (70.2 wt % in the composite) at the current density of 0.4 A g^?1, which is higher than that of PPy/CNTs/MF (120 F g^?1 based on the total mass of the composite and 167 F g^?1 based on the mass of the PPy). Furthermore, the capacitor assembled by CNTs/PPy/CNTs/MF shows excellent cyclic stability. The capacitance of the cell assembled by CNTs/PPy/CNTs/MF retains 96.3% over 450 scan cycles at scan rate of 20 mV s^?1, which is larger than that assembled by CNTs/PPy/MF (72.5%). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39779.     

Selective Laser Sintering 3D Printing: A Way to Construct 3D Electrically Conductive Segregated Network in Polymer Matrix

Selective laser sintering (SLS), which can directly turn 3D models into real objects, is employed to prepare the flexible thermoplastic polyurethane (TPU) conductor using self‐made carbon nanotubes (CNTs) wrapped TPU powders. The SLS printing, as a shear‐free and free‐flowing processing without compacting, provides a unique approach to construct conductive segregated networks of CNTs in the polymer matrix. The electrical conductivity for the SLS processed TPU/CNTs composite has a lower percolation threshold of 0.2 wt% and reaches ≈10⁻¹ S m⁻¹ at 1 wt% CNTs content, which is seven orders of magnitude higher than that of conventional injection‐molded TPU/CNTs composites at the same CNTs content. The 3D printed TPU/CNTs specimen can maintain good flexibility and durability, even after repeated bending for 1000 cycles, the electrical resistance can keep at a nearly constant value. The flexible conductive TPU/CNTs composite with complicated structures and shapes like porous piezoresistors can be easily obtained by this approach.     

Preparation and morphology of electrically conductive and transparent poly(vinylchloride)-polypyrrole composite films

Summary The chemical process of preparing poly(vinylchloride)-polypyrrole composite films with high electrical conductivity and transparency has been studied. Pyrrole has been diffused into the poly(vinylchloride) matrix in the swelling medium of n-hexane and acetone mixture. The oxidative polymerization of the diffused pyrrole in the binary solvent system of acetonitrile and methanol gives high conductivity of the polypyrrole as well as the good penetration of the oxidant into the PVC polymer matrix. The analytical testing of the composite film shows the formation of homogeneous mixture of polypyrrole and poly(vinylchloride) conductive layer within the 1.0m of thickness on the film surface. The transparency of the composite film showed about 50–60% at 500 nm. The electrical conductivity of the composite was about 20 s/cm.     

Conducting poly(styrene‐co‐divinylbenzene)/polypyrrole PolyHIPE composite foam prepared by chemical oxidative polymerization

Conducting poly(styrene‐co‐divinylbenzene)/polypyrrole (PPy) polyHIPE (polymerized high internal phase emulsion) composite foams were synthesized via chemical oxidative polymerization method. The effect of solvent and dopant type on the surface morphology and electrical conductivity of composite foams has been investigated. SEM micrographs showed that the morphology of PPy thin film on the internal surface of poly(styrene/divinylbenzene) (poly(St‐co‐DVB) polyHIPE support foam strongly depends on the solvent and dopant type used. Incorporation of dodecylbenzene solfunic acid‐sodium salt (DBSNa) as a dopant in chloroform solvent resulted in formation of a PPy thin film with higher molecular compact structure and electrical conductivity on the support foam as compared to other solvents and another dopant used. Fourier‐transform infrared spectroscopy was used to correlate the electrical conductivity of composite foams to their PPy structural parameters. As expected, the extended conjugation length of PPy in the presence of DBSNa dopant is the main reason for higher electrical conductivity of resultant composite foam. Electrical conductivity measurements revealed that the chemical aging of various conducting foams follows the first‐order kinetic model, which is a representative of a reaction‐controlled aging mechanism. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A study of the electrical properties of carbon nanotube-NiFe2O4 composites: Effect of the surface treatment of the carbon nanotubes

Novel carbon nanotube-NiFe₂O₄ composite materials have been prepared for the first time by in situ chemical precipitation of metal hydroxides in ethanol in the presence of carbon nanotubes (CNTs) and followed by hydrothermal processing. The obtained composite powders were characterized using XRD, TEM and EDS. The effect of surface oxidation treatment of CNTs on their properties was investigated by FTIR, zeta potential and hydrodynamic radius distribution characterization. Electrical conductivity measurements show that surface oxidation treatment of CNTs can improve the electrical conductivity of the composites more pronouncedly than pristine CNTs do. With 10 wt.% addition of surface treated CNTs, the electrical conductivity is increased by 5 orders of magnitude. The surface oxidized CNTs are crucial for this significant increase in electrical conductivity, which provides strong adhesion between the nanotubes and the matrix to give a homogeneous carbon nanotube-NiFe₂O₄ composite.     

Chemical Grafting of Crosslinked Polypyrrole and Poly(vinyl Chloride) onto Modified Graphite: Fabrication,Characterization, and Material Properties

ABSTRACT

Conjugated polymer/graphite nanocomposites have been known as high performance materials owing to improve the physicochemical properties relative to conventional once. Multilayered polymer nanocomposites based on polypyrrole (PPy), polyvinylchloride (PVC) as matrices and p-phenylene diamine (PDA) as linker were prepared via chemical in situ polymerization process and subsequently investigated the physical characteristics of fabricated nanocomposites at various loadings. The structural characterization and morphology of prepared nanocomposites were inspected by Fourier transform infrared spectroscopy (FTIR), X-ray photon spectroscopy (XPS), energy dispersive X-ray spectroscope (EDX), field emission scanning electron microscope (FESEM), respectively. The composite III showed higher thermal stability at 10 wt% loading of PPy. According to differential scanning calorimetry (DSC), the glass transition temperature (T_g), melting temperature T_m, and crystallization temperature (T_c) of nanocomposites increases with PPy loading (2–10 wt%) owing to crosslinking and chain rigidity. Moreover, higher surface area was displayed by the multilayered PPy/PVC/PDA@FG nanocomposites. Remarkably, electrical conductivity of ultimate nanocomposites was also found to be a function of PPy loading.     

Electrically conductive composites of polyurethane derived from castor oil with polypyrrole‐coated peach palm fibers

Electrically conducting fibers were prepared through in situ oxidative polymerization of pyrrole (Py) in the presence of peach palm fibers (PPF) using iron (III) chloride hexahydrate (FeCl₃·6H₂O) as oxidant. The polypyrrole (PPy) coated PPF displayed a PPy layer on the fibers surface, which was responsible for an electrical conductivity of (2.2 ± 0.3) × 10⁻¹ S cm⁻¹, similar to the neat PPy. Electrically conductive composites were prepared by dispersing various amounts of PPy‐coated PPF in a polyurethane matrix derived from castor oil. The polyurethane/PPy‐coated PPF composites (PU/PPF–PPy) exhibited an electrical conductivity higher than PU/PPy blends with similar filler content. This behavior is attributed to the higher aspect ratio of PPF–PPy when compared with PPy particles, inducing a denser conductive network formation in the PU matrix. Electromagnetic interference shielding effectiveness (EMI SE) value in the X‐band (8.2–12.4 GHz) found for PU/PPF–PPy composites containing 25 wt% of PPF–PPy were in the range −12 dB, which corresponds to 93.2% of attenuation, indicating that these composites are promising candidates for EMI shielding applications. POLYM. COMPOS., 38:2146–2155, 2017. © 2015 Society of Plastics Engineers     

Fabrication of polypyrrole (PPy)/carbon nanotube (CNT) composite electrode on ceramic fabric for supercapacitor applications

Polypyrrole (PPy)/carbon nanotube (CNT) composite electrodes are fabricated on ceramic fabrics for electrochemical capacitor applications. The CNTs are grown on the ceramic fabrics by the chemical vapor deposition (CVD) method and PPy is subsequently coated on them by chemical polymerization. The large surface area and high conductivity of the CNTs on the porous ceramic fabrics enhance their energy storage capacity. PPy provides not only additional capacitance as an active material, but also enhances the adhesion between the CNTs and ceramic fabrics. Furthermore, PPy acts as a conducting binder for connecting every individual CNT to increase the capacitance. The morphology of the PPy–CNTs on the ceramic fabrics is confirmed by SEM and TEM, and the electrochemical characteristics are investigated by cyclic voltammetry and galvanostatic charge–discharge tests.     

Microcellular Conductive Carbon Black or Graphene/PVDF Composite Foam with 3D Conductive Channel: A Promising Lightweight,Heat-Insulating,and EMI-Shielding Material

In this study, a lightweight microcellular carbon-based filler/poly(vinylidene fluoride) (PVDF) composite foam is fabricated with a 3D conductive network that is thermally insulating, electrically conductive, and fabricated on a large scale. This composite can be used for high-efficiency thermal insulation and electromagnetic interference (EMI) shielding applications. The prepared composite demonstrates low density, high electrical conductivity, and excellent thermal insulation properties. The structure and density of the conductive network and the carbon-based filler content has a significant influence on the electrical conductivity of the prepared composite foam. Although the composite comprises microcellular PVDF beads of the same density, the conductivity of the composite-comprising strip beads is greater than that comprising spherical beads. In the same conductive network structure, as the size of the microcellular PVDF beads decrease, the conductive network becomes denser, which results in a higher conductivity. Furthermore, with an increase in the conductive filler content, the conductivity improves significantly. Excellent EMI shielding materials with optimal filler content and particle shapes, exhibiting EMI shielding effectiveness of up to 40–50 dB, are developed. The prepared composite foam possesses excellent application potential in the fields of ultra-light thermal insulation, conductivity, and EMI shielding.