PPy／SiO2纳米复合材料的合成与导电性能

以乙醚反应介质，用化学方法合成了聚吡咯纳米复合材料，利用红外光谱，四探针技术和透射镜表征了这些材料的组成，结构和导电性能，结果表明，载流子在ＰＰｙ分子链之间和ＰＰｙ聚集体之间有的传导性。     

Fe3O4磁性纳米颗粒的合成及其调控

利用水解共沉淀法制备了Fe3O4纳米颗粒,研究了温度和pH值对Fe3O4纳米颗粒粒径、形貌的影响关系。研究结果表明,反应温度从30℃升高到90℃,Fe3O4颗粒的粒径从6～8nm增大到10～12nm;同时,Fe3O4颗粒的饱和磁矩也随着Fe3O4颗粒粒径的增加而升高。溶液pH值会影响Fe3O4纳米颗粒的形状,高pH值易使合成的Fe3O4纳米颗粒为四方形,随着pH值的降低,Fe3O4纳米颗粒向球形转变。Fe3O4纳米颗粒的粒径和形状的可控性为进一步合成、调控Fe3O4电磁功能复合材料奠定了良好基础。     

导电聚合物/无机纳米复合材料的研究进展

主要介绍了导电聚合物/无机纳米复合材料的制备方法,详细评述了各种制备方法的优缺点,总结了导电聚合物/无机纳米粒子复合材料性能的改善与应用领域,并展望了导电聚合物/无机纳米粒子复合材料的研究方向和应用前景.     

AS/石墨纳米薄片复合材料的制备

通过把膨胀石墨进行超声处理制备了石墨纳米薄片(FG).并对挤出成型制备AS/石墨纳米薄片导电复合体系的工艺过程进行了研究,测试了纳米复合材料的渗滤阈值,其渗滤阈值为9～10%(质量分数).     

聚合物/石墨导电纳米复合材料研究进展

石墨是近几年国内外研究的热点无机层状材料之一,它与聚合物有效复合形成的纳米复合材料是一类具有广阔应用前景的新型材料。从石墨的应用形式、聚合物基体的种类、复合材料的制备方法几个方面概述了聚合物/石墨导电纳米复合材料的研究进展及其发展趋势。     

细菌纤维素基磁性纳米复合材料的研究进展

细菌纤维素作为一种新型的生物纳米材料,不同于植物纤维素,其较高的比表面积、精细的三维纳米网状结构和表面大量的活性反应位点可以作为"模板"反应使用,通过原位复合的方法可有效地控制、合成具有预期特定形貌与尺寸且分布均匀的磁性纳米复合材料,从而获得良好的综合性能。从细菌纤维素作为"模板"制备功能化材料的机理出发,归纳总结了近年来细菌纤维素基磁性材料的研究进展,着重归纳了解决磁性膜材料的颗粒团聚问题的方法,并展望了细菌纤维素基磁性材料的发展趋势。     

PPy／SiO2纳米复合材料导电机理的研究

在水介质中的化学方法合成了ＰＰｙ／ＳｉＯ２纳米复合材料，并利用元素分析，四探针技术和透射电镜等研究了它的导电机理。结果表明，载流于可以分子链内，分子链之间和聚合物聚集体颗粒之间传导。     

导电聚合物／无机纳米复合材料的研究进展

主要介绍了导电聚合物／无机纳米复合材料的制备方法，详细评述了各种制备方法的优缺点，总结了导电聚合物／无机纳米粒子复合材料性能的改善与应用领域，并展望了导电聚合物／无机纳米粒子复合材料的研究方向和应用前景。     

PPy/TiO2纳米复合材料的制备及光催化活性

采用原位聚合的方法合成了聚吡咯/二氧化钛(PPy/TiO2)纳米复合材料,研究了吡咯(Py)与TiO2的比例、氧化剂的种类、掺杂酸的浓度等因素对PPy/TiO2纳米复合材料在太阳光下光催化降解甲基橙的影响,采用透射电镜、紫外-可见漫反射吸收光谱等方法对样品进行了表征.结果表明,PPy/TiO2纳米复合粒子在太阳光下的光催化活性明显高于TiO2纳米粒子,当Py与TiO2的比例为1:100,三氯化铁为氧化剂,1.0mol·L-1盐酸溶液为掺杂剂时PPy/TiO2纳米复合粒子在太阳光下的光催化活性最高;TiO2纳米微粒以及PPy/TiO2纳米复合微粒的粒径均为10～20nm,复合微粒的粒径没有明显的增大,但是减轻了纳米粒子之间的团聚;聚吡咯使TiO2纳米粒子的禁带宽度由3.12eV降低到2.84eV,TiO2纳米粒子的吸收波长拓展到可见光区,有利于TiO2纳米粒子在太阳光下光催化活性的提高.     

PPy/APS-SiO2纳米导电复合材料的合成与表征

用化学氧化聚合复合方法合成聚吡咯／二氧化硅(PPy／SiO2)纳米复合材料。首先用不同百分含量的氨丙基三乙氧基硅烷(APS)处理SiO2，然后以水为反应介质，通过化学聚合方法合成PPy／APS—SiO2纳米复合材料，并利用红外光谱、热失重、X射线光电子能谱(XPS)、透射电镜和四探针等手段进行表征。结果表明，用APS处理过的SiO2合成的复合材料PPy含量增加，且通过XPS看出PPy／APS—SiO2表面富有PPy，而PPy／SiO2表面富有SiO2。其中用1％APS—SiO2合成的复合材料电导率最高，为38．46S／cm。     

Dynamic mechanical analysis and non-isothermal kinetics of EVA/PPy carbon black nanocomposites

Pure ethylene-co-vinyl acetate (EVA) and its conductive blend-nanocomposite with polypyrrole (PPy)/carbon black (CB) were prepared using a melt mixing process. Dynamic mechanical analysis and non-isothermal thermal gravimetrical analysis were performed on the samples. The storage modulus, loss modulus, and damping factor of the EVA/PPy/CB nanocomposites were significantly affected by the incorporation of PPy/CB. Two thermal decomposition stages were detected for pure and blended nanocomposite samples. Peak analysis was used to deconvolve the first complex decomposition stage. The Coats-Redfern method was used to determine the kinetic parameters. Improving the thermal and mechanical properties of the EVA co-polymer will enable the three-phase blend/nanocomposites to be used in several industrial applications.     

无定形炭/磁性粒子复合吸波材料的制备和电磁性能研究

以二甲基亚砜(DMSO)为溶剂进行溶液聚合制得聚丙烯腈(PAN)溶液,在此溶液中混入了微米级铁粉后将其压成薄膜,将烘干后的薄膜高温碳化处理制得一种碳基吸波材料。采用X射线衍射(XRD)、扫描电镜(SEM)等手段对材料的成分、形貌、结构进行了表征。采用矢量网络分析仪对该复合材料在2～18GHz频段内的电磁参数进行了测试,并作了微波反射率的数值模拟。研究了碳化温度对材料物相组成和电磁性能的影响以及碳化温度和涂层厚度对材料吸波性能的影响。此种吸波材料是无定形炭和铁的氧化物、铁的氮化物等磁性物质的复合材料,兼有电损耗和磁损耗,具有较好的吸波性能。     

Evolution of hollow dodecahedron carbon coated FeCo with enhance of electromagnetic properties

FeCo@C with a hollow porous dodecahedron structure was obtained through carbonization of ZIF-67 etched with Fe³⁺. During the pyrolysis process, the organic skeleton of the ZIF-67 was carbonized, forming graphitic carbon and carbon nanotubes. The etching effect of Fe³⁺ with different concentrations on the morphology of ZIF-67 is studied. The MOF-derived porous carbon bimetallic nanocomposites exhibited stronger electromagnetic wave absorption performance than the monometallic ones. Specifically, the optimized sample has a reflection loss of ?70.69 dB at 11.28 GHz, as the thickness is 2.07 mm. The enhanced electromagnetic wave (EMW) absorption performance of the nanocomposites can be attributed to the multiple interfaces and capacitive structure formed by catalytically produced carbon nanotubes. This achievement could be used as a reference for the development of MOF-derived porous carbon nanocomposite EMW absorbers.     

Co-Ni@N-C/多孔碳复合材料的制备及电磁特性

以制备的多孔碳为基材,采用热还原法通过原位生长制备轻质化Co-Ni@N-C/多孔碳复合材料,研究了多孔碳的添加量对样品电磁波吸收性能的影响。采用X射线衍射仪(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、拉曼光谱(Raman)对样品的相结构、组分和微观形貌进行表征。通过矢量网络分析仪对样品在2～18 GHz频段内的电磁参数进行测试,并根据传输线理论分析了样品的电磁波吸收性能。结果表明：以多孔碳为基材制备的Co-Ni@N-C/多孔碳样品,当多孔碳含量占原材料总质量的2.7%时,样品具有良好的电磁波吸收性能,最大反射损耗值为-57.74 dB(15.12 GHz, 2.35 mm),最大有效吸收带宽为5.14 GHz(12.86～18 GHz, 2.25 mm),基本覆盖整个Ku波段。     

M型钡铁氧体制备及吸波特性研究

为进一步研究M型铁氧体的吸波性能,以硝酸铁、硝酸钡为原料,采用溶胶凝胶自蔓延法,制备了M型钡铁氧体纳米粉.借助XRD、TG-DTA、SEM、矢量网络分析仪对铁氧体材料的晶体结构、凝胶热分解过程、表面形貌及微波吸收特性进行了研究,同时根据传输线原理,通过理论计算预测了材料的最佳匹配厚度.研究表明:所制得的铁氧体为晶相单一的M型钡铁氧体,频率在6～18GHz,预测最佳匹配厚度为0.35cm,最小反射损耗达-13.5dB,反射损耗小于-10dB的带宽为0.7GHz,说明M型钡铁氧体具有电磁波吸收效应.     

Facile synthesis and wide-band electromagnetic wave absorption properties of carbon-coated ZnO nanorods

In this work, a facile and scalable acetylene decomposition method was employed to synthesize carbon-coated ZnO (ZnO@C) nanorods. The characterization of morphology and structure analysis demonstrate that ZnO nanorod was well coated by an amorphous carbon shell with a thickness of about 20 nm. Comparted with ZnO, ZnO@C exhibit significantly enhanced microwave absorption properties. The effective absorption bandwidth with RL values exceeding –10 dB can reach 5.3 GHz for ZnO@C with a matching thickness of 2.5 mm. The excellent microwave absorption arose from enhanced dielectric loss caused by interfacial polarization, dipole polarization and the formation of conductive network.     

Synthesis and characterization of multiwalled carbon nanotube/FeCo nanocomposites

Multiwalled carbon nanotube/FeCo nanocomposites were produced by Catalytic Chemical Vapour Deposition using highly porous FeCo-SiO2 aerogels with different loadings and dimensions of FeCo nanoparticles as catalysts. Multiwalled carbon nanotubes with average number of walls depending on the size of the catalyst nanoparticles were obtained. Inside the nanotubes spherical or elliptical FeCo nanoparticles are retained, and the magnetic properties of the resulting nanocomposites were characterized in detail.     

Synergistic effects of micro-/nano-fillers on conductive and electromagnetic shielding properties of polypropylene nanocomposites

This study presents the synergistic effects of graphene nanosheets (GNSs) and carbon fibers (CFs) additions on the electrical and electromagnetic shielding properties of GNS/CF/polypropylene (PP) composites. These composites were fabricated by the melt blending of different ratios of GNSs and CFs (20:0, 15:5, 10:10, 5:15 and 0:20 wt/wt%) into a PP polymer matrix using a Brabender mixer. Besides, the chemical and crystalline structures and the thermal stability of the resultant GNS/CF/PP composites were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). FT-IR and XRD showed that with the addition of GNSs content, transmittances at 1373.4?cm^?1 and 1454.4?cm^?1 became smaller and the characteristic peak at 26.82° became stronger. TGA showed that the GNS/CF/PP composite can be used at high temperature below 456°C. Blending 10?wt% CFs and 10?wt% GNSs into the PP polymer resulted in excellent conductivity (0.397 S/cm), which indicated the occurrence of the critical percolation threshold phenomenon, and also reached the maximum electromagnetic shielding effectiveness (EMSE) of 20?dB at 1.28–2.00?GHz. Laminated with five layers of composites, its EMSE achieved 25–38?dB at 0.3–3.0?GHz, corresponding to blocking of 94.38–98.74% electromagnetic waves.     

Preparation and electromagnetic wave absorption properties of hollow Co,Fe@air@Co and Fe@Co nanoparticles

In this study, hollow Co, Fe@air@Co and Fe@Co nanoparticles (NPs) have been synthesized respectively by electroless plating Co shell on Fe core and controlling reaction time based on galvanic cell reaction between Co shell and Fe core in hydrochloric acid at room temperature. The electromagnetic (EM) wave absorption properties of these three NPs are also been investigated. The results indicate that the relationship between Fe core and Co shell is critical to the EM wave absorption properties of hollow Co, Fe@air@Co and Fe@Co nanoparticles when blended with 70?wt% in paraffin-based samples. Fe@air@Co nanoparticles shows the best EM wave absorption properties with minimum reflection loss of ?42.75?dB and effective bandwidth of 4.1?GHz under ?10?dB. The present work has a significant potential for the development of EM wave absorbing materials with core-shell structure.     

宽频带橡胶复合铁氧体电磁波吸波材料研究

采用M型六角晶系铁氧体材料与橡胶复合构成宽频带、薄型电磁波吸波材料。介绍了材料配方、制备工艺与特性。用弓形法，在2～18GHz频率范围研究了这种复合吸波材料的反射率特性，通过合理组合成复合吸波材料，当总厚度为20mm时，可在2～18GHz频率范围实现反射率≤-10dB。