Preparation and characterization of polypyrrole/selenium composites

This article reports synthesis of polypyrrole (PPy) and its composites having various amounts of selenium (Se) in the presence of nitric acid in aqueous medium via chemical oxidative polymerization. Samples were spectroscopically characterized using Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, and atomic absorption spectroscopy. Although morphology of the samples was examined by using scanning electron microscopy (SEM), their thermal properties were studied via differential scanning calorimetry (DSC). The alternating current (ac) conductivity and dielectric properties were investigated as a function of temperature. Variation of adsorption free energy obtained from Langmuir adsorption isotherm showed that metal cations were physically adsorbed onto the polymer surface. SEM images showed that filling process significantly changes the morphology of PPy. DSC results indicated that cold crystallization temperature (T_cc) of unfilled PPy decreases with increasing filling level. Dielectric measurements showed that relaxation times for PPy and its composites have decreased linearly with increasing temperature. The conductivity of the PPy, when filled with 1 g of Se, increased ～ four times at room temperature for 1 kHz. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

聚吡咯/氧化石墨烯复合材料的制备及电化学性能研究

分别采用物理球磨混合法、化学原位聚合法和化学原位聚合-还原法制备了聚吡咯/氧化石墨烯混合物、聚吡咯/氧化石墨烯(PPy/GO)和聚吡咯/还原氧化石墨烯(PPy/RGO)复合材料。通过三电极测试其电化学性能(循环伏安、恒流充放电和交流阻抗)。结果表明,通过化学原位聚合法制备的PPy/GO(304. 5 F/g)比电容远高于物理混合(16 F/g)和聚吡咯/还原氧化石墨烯(126. 4 F/g)。化学法原位聚合法制备PPy/GO最佳条件是冰浴条件下和加入表面活性剂对羟基苯磺酸钠。并通过X射线衍射(XRD)和扫描电子显微镜(SEM)对化学原位制备的PPy/GO组成、结构和形貌进行了表征。     

一步水热法合成铜改性的介孔γ-Al_2O_3及其吸附脱硫性能研究

采用一步水热合成法,以Al(NO3)3为铝源,P123为模板剂,Na OH、Na2CO3和K2CO3分别为沉淀剂,Cu(NO3)2为铜源,制备出负载铜的金属有序介孔γ-Al2O3,并运用N2吸附-脱附和XRD等技术对其结构进行表征,同时探讨了铜改性的介孔γ-Al2O3对模型燃油中的噻吩的吸附性能。结果表明,这3种沉淀剂都能制备出比表面积大(>226 m2/g),孔径分布中心为3.3 nm,孔体积为0.27⁰.35 cm3/g的负载铜的介孔γ-Al2O3,且样品都保持了较好的介孔结构。样品对模型燃油中噻吩的吸附脱硫性能表明,用Na OH作为沉淀剂且负载铜的介孔γ-Al2O3样品对噻吩的吸附性能较好,原因在于此样品具有较大的比表面积且铜在此样品中的分散性较好。     

Preparation and characterization of composites of polypyrrole

In this paper, we report the preparation and characterization of composites of polypyrrole (PPy) with polyvinylidene fluoride (PVDF), and cellulose. We used the techniques of chemical and electrochemical polymerization. These materials were characterized using X-ray diffraction (wide and small angle (SAXS)), electrical conductivity and electron microscopy. The studies showed that homogeneous composites could be formed. The percentage crystallinity of the host polymer decreased, whereas some crystallization of PPy was noticed. SAXS studies revealed that the diffusion of PPy is in amorphous regions. The electrical conductivity of the composites was found to vary in the range of 10^?8 S/cm to 10^?4 S/cm. These composites were found to be useful in gas sensors for detection of chlorine and ammonia.     

Preparation and characterization of silylated graphite oxide

Graphite oxide was silylated by various alkylchlorosilanes in the presence of butylamine and toluene, and new intercalation compounds were obtained. The silylating reagents with two or three chlorine atoms at silicon in them reacted with graphite oxide, while no reaction occurred when silylating reagents with only one chlorine atom was used. The silylating reagent mainly reacted with hydroxyl group of graphite oxide, forming Si-O bonding. The role of butylamine was not only exfoliating graphite oxide layer but also scavenging HCl molecule which caused the decomposition of silylated graphite oxide. The silicon content was almost constant ≈0.6 mol/graphite oxide for the samples silylated by alkyltrichlorosilane with shorter alkyl chain lengths. It increased with the increase of alkyl chain length and reached 1.7 mol/graphite oxide. The higher silicon content could be ascribed to further silylation on hydroxyl groups formed at silicon atoms of silylating reagent bonded to graphite oxide, bridging two silylating reagents.     

新型钆石墨层间化合物复合材料的制备及表征

通过Hummers法制备氧化石墨,并以化学吸附法将氯化钆（GdCl3）饱和溶液中的钆离子引入氧化石墨（GO）,合成新型水合碳酸氧钆-氧化石墨层间化合物复合材料。采用XRD、FT-IR和TG-DTA对产物进行分析表征。表明,制备水合碳酸氧钆-氧化石墨层间化合物的最佳质量配比为m（Gd2O3）∶m（EG）=5∶1。通过TG-DTA分析确认,水合碳酸氧钆-氧化石墨层间化合物的还原温度为480℃。     

Preparation and characterization of maleated polylactide-functionalized graphite oxide nanocomposites

Organically dispersible graphene nanosheets were fabricated by amine surfactant intercalated graphite oxide (GOAs) with ultrasonication below room temperature. Subsequently, GOAs filled nanocomposites of polylactide grafted with maleic anhydride (PLAgMA) were prepared directly by solution blending. The compatibilization effects provided by the functionalization of both constituents and their influence on the structure and properties of the final nanocomposites in different compositions were investigated. The interactions and structural morphology of the nanocomposites were examined by Fourier transform infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopy. Thermal, dynamic-mechanical and conductive properties of these nanocomposites were investigated as a function of GOAs content. The detailed morphological and X-ray diffraction results revealed that the degree of GOAs dispersion enhanced with maleated PLA. Study of the dynamic-mechanical properties showed that both the storage modulus G’ and the loss modulus G” are very sensitive to the microstructure of the nanocomposite. The thermal properties of the nanocomposites were significantly influenced by the GOAs content due to the shielding and nucleating effect of exfoliated layers. Both the thermal and electrical conductivities showed substantial improvements with increasing GOAs content. The overall results pointed to the compatibilization synergy of GO functionalization and PLA maleation.     

Preparation of two-dimensional graphite oxide modified chlorinated polyethylene rubber composites

<正>Herein,a two-dimentional graphite oxide (GO) modified chlorinated polyethylene rubber(CM) was utilized to prepare GO/CM composite. The vulcanization system which is suitable for this composite was     

聚吡咯/二氧化锰复合材料的制备及其电化学性能研究

利用水热法合成了海胆状MnO_2,通过吡咯聚合制备了PPy@MnO_2复合结构,研究了包覆时间、包覆量对PPy@MnO_2电化学性能的影响。用PPy@MnO_2纳米复合材料作为工作电极,在1 mol/L的Na_2SO_4溶液中利用三电极体系进行了电化学性能测试。PPy@MnO_2纳米复合材料的循环伏安、恒电流充放电和电化学阻抗谱(EIS)研究表明,PPy@α-MnO_2-60纳米复合材料在吡咯与二氧化锰质量比10∶1、包覆时间6 h时电化学性能最佳,在电流密度0.5 A/g时比电容值为177.3 F/g。     

Electrochemical inspection of polypyrrole/chitosan/zinc oxide hybrid composites

Polymer nanocomposite composed of polypyrrole, chitosan, and zinc oxide nanoparticles has been synthesized and it has been evaluated for various electrochemical aspects of the current electrochemical industry. The polypyrrole (PPy) was synthesized by the chemical oxidative polymerization reaction by employing ammonium persulfate as oxidizing agent. Composites of polypyrrole/chitosan (PPy/Chy) and polypyrrole/chitosan/ZnO (PCZ) composites were synthesized by the solution blending method. Detailed structural, morphological, thermal characterization of PPy, PPy/Chy, and PCZ were performed to characterize the specific features of the systems. The composites exhibit better thermal stability and high surface area and the addition of ZnO nanoparticle increase the crystallinity of the composite. Electrochemical characterization of the ITO electrodes modified with PPy, PPy/Chy, and PCZ were performed using cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry techniques. The present study highlights the role of a bio-compatible material with high surface area and conductive constituent for designing of various high performing electronic noninvasive sensors, biosensors, and so forth.     

Preparation and characterization of manganese oxide/CNT composites as supercapacitive materials

Manganese oxide was synthesized and dispersed on carbon nanotube (CNT) matrix by thermally decomposing manganese nitrates. CNTs used in this paper were grown directly on graphite disk by chemical vapor deposition technique. The capacitive behavior of manganese oxide/CNT composites was investigated by cyclic voltammetry and galvanostatic charge–discharge method in 1 M Na₂SO₄ aqueous solutions. When the loading mass of MnO₂ is 36.9 μg cm^− 2, the specific capacitance of manganese oxide/CNT composite (based on MnO₂) at the charge–discharge current density of 1 mA cm^− 2 equals 568 F g^− 1. Additionally, excellent charge–discharge cycle stability (ca. 88% value of specific capacitance remained after 2500 charge–discharge cycles) and power characteristics of the manganese oxide/CNT composite electrode can be observed. The effect of loading mass of MnO₂ on specific capacitance of the electrode has also been investigated.     

石墨/PMMA的制备与表征

以鳞片石墨和甲基丙烯酸甲酯(PMMA)为原料,采用悬浮聚合的方法制备出石墨/PMMA复合材料,并对此材料的结构和性能进行表征.实验结果表明,以石墨为填料对PMMA进行改性,可有效地改善PMMA的导热性能.     

石墨/PS复合材料的制备与表征

以鳞片石墨和聚苯乙烯为原料,采用悬浮聚合的方法制备出石墨/PS复合材料,并对此材料的结构和性能进行了表征.实验结果表明,以石墨为填料对PS进行改性,可有效地改善PS的导热性能.     

聚吡咯/凹凸棒土纳米复合材料的制备及结构表征

以十二烷基磺酸钠为掺杂剂,FeCl3·6H2O为氧化剂,引发吡咯单体（Py）发生化学氧化聚合,制备出聚吡咯/凹凸棒土纳米复合材料（PPy/ATP）,并通过XRD、TG-DTA、FTIR和TEM等技术手段对所得的复合材料进行了表征。体积电阻率测量表明,随着Py用量的增大,纳米复合材料的体积电阻率逐渐变小,当Py/ATP的质量比≥0.25时体积电阻率变化不大。XRD和TEM显示,聚吡咯以非晶态形式包覆在凹凸棒土单晶的表面,形成核-壳棒状纳米结构,包覆层厚度约为2 nm。TG-DTA表明凹凸棒土纳米复合材料的耐热性能与纯聚吡咯相比明显提高。FTIR表明纳米复合材料中聚吡咯与凹凸棒土之间存在物理作用。     

Fabrication and characterization of multilayer SiO2/polymethacrylic acid/polypyrrole composites and hollow polypyrrole microspheres

Methacrylic acid was polymerized on the 3‐(methacryloxy)propyl trimethoxysilane‐modified silica core. The carboxylic acid groups of polymethacrylic acid (PMAA) not only provide the “active‐sites” for growth of the pyrrole monomers but also act as doping acids for polypyrrole (PPy). By in situ polymerization route, SiO₂/PMAA/PPy multilayer composites and hollow PPy microspheres with controllable shell thickness were fabricated. The morphologies, sizes, and structures of the nanocomposites were investigated in detail by transmission electron microscopy, scanning electron microscopy, Fourier‐transform infrared spectra, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

纳米石墨片/环氧树脂复合材料的制备及性能

分别采用低温固化剂和高温固化剂制备了纳米石墨片/环氧树脂复合材料。通过电阻测试仪和材料试验机研究了纳米石墨片的含量对复合材料导电性能和力学性能的影响规律,并将溶液混合法与直接混合法制备的复合材料的性能进行对比,同时比较了纳米复合材料的性能与微粉石墨/环氧树脂复合材料的性能。结果表明,溶液混合法制备的复合材料逾渗阈值更低,可得到填料质量分数达60%、体积电阻率为0.0085 Ω·cm的纳米复合材料。当填料质量分数高于4%时,纳米复合材料的力学性能低于微粉复合材料。     

Preparation and characterization of carboxymethyl polyvinyl alcohol–graphite nanosheet composites

Carboxymethyl polyvinyl alcohol (CMPVA) was prepared by introducing carboxymethyl groups to polyvinyl alcohol (PVA) with chloroacetic acid. Graphite nanosheets (NanoG) were obtained by treating expandable graphite at a high temperature in a muffle furnace, and then sonicating it in an aqueous ethyl alcohol solution. Nanocomposites of CMPVA with NanoG were prepared by dispersing NanoG in a CMPVA aqueous solution with the aid of sonication and then casted on plastic film to remove water. Carboxymethyl groups were proved to be linked to PVA by Fourier transform infrared (FTIR) spectra and the degree of carboxymethyl substitution on the PVA was 2.77% determined by conductometric titration. Experimental results show that carboxylate anions in introduced carboxymethyl groups facilitate the dispersal of NanoG with positive charges in the CMPVA solution. The CMPVA matrix was detected by X‐ray diffraction (XRD) and FTIR spectra to be less crystal, into which NanoG tend to disperse. Scanning electron microscopy was used to characterize the structure of the graphite and morphology of the composites to prove that NanoG was 40–70 nm thick. The percolation threshold of CMPVA/NanoG composites at room temperature was as low as 0.80 wt%. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Fabrication and characterization of ultrafine graphite/carbon foam composites

Journal of Porous Materials - Ultrafine graphite/carbon foam composites were prepared by direct pyrolysis of ultrafine graphite/mesophase pitch mixtures at high pressure, via foaming and...     

碳纳米管增强环氧／石墨复合材料的制备与性能研究

采用粉末冶金法制备了碳纳米管增强环氧／石墨复合材料,并研究了酸洗处理对复合材料弯曲强度、硬度和导电性能的影响。结果表明：与未处理碳纳米管相比,酸处理的碳纳米管增加了环氧／石墨复合材料的弯曲强度和硬度,降低了电阻率。酸处理的碳纳米管增强环氧／石墨复合材料的弯曲强度达到21．9MPa,比未添加碳纳米管时提高了近22％;同时复合材料的硬度达到最大值21．7HS,比未添加碳纳米管时提高了近10％;复合材料的电阻率达到了最小值45036μΩ·cm,比未添加碳纳米管时复合材料的电阻率降低了近17％。