纤维素纳米纤丝-碳纳米管/天然橡胶柔性导电弹性体的合成与性能

利用纤维素纳米纤丝(Cellulose nanofibers,CNFs)搭载碳纳米管(Carbon nanotubes,CNTs)均匀分散在天然橡胶(Natural rubber,NR)基体中,制备了具有高强度和高柔韧性的复合导电弹性体(CNF-CNT/NR)。通过对其化学结构、微观结构、力学性能和电学性能等研究发现,CNFs能有效协助CNTs在NR基体中均匀分散,使得弹性体的力学性能和电学性能显著提高。当CNFs和CNTs含量分别为3和10 phr时,CNF-CNT/NR的强度和弹性模量可达6.44±0.32 MPa和8.77±0.48 MPa,约为纯NR的6.9和9.96倍,CNT/NR的1.49和1.59倍;其电导率可达1.78±0.86 S/m,在电流密度为0.3 A/g时比电容可达107 F/g;1.0 A/g的电流密度下循环充放电1 200次,其比电容仍为初始值的83%。该柔性导电弹性体具有优良的机械性能和电学性能,有望应用于柔性电子器件领域。     

聚吡咯/纳米二氧化钛的制备及电化学性能

采用化学原位聚合的方法制备了聚吡咯/二氧化钛(PPy/TiO_2)复合物,其中聚吡咯和二氧化钛的质量比分别为1∶1、2∶1、3∶1、4∶1,将其作为电化学超级电容器的电极材料,采用扫描电子显微镜和X射线衍射仪研究了PPy/TiO_2的形貌和相组成,通过电化学测试研究了PPy/TiO_2的电化学性能.结果表明:TiO_2均匀地包覆在PPy基体中,PPy/TiO_2的电化学性能明显优于纯PPy;当PPy与TiO_2的质量比为3∶1时复合材料的电化学性能最佳,即在2 A/g充放电电流密度下,其比电容达到了255.68 F/g,比纯PPy提高了2倍左右;在1 A/g充放电电流密度下,循环充放电1 000圈之后PPy/TiO_2的比电容保持率为87.2%,纯PPy的比电容保持率仅为46.9%.     

基于界面相互作用构建纳米纤维素-羧基化碳纳米管-石墨/聚吡咯柔性电极复合材料

以纳米纤维素(CNF)、羧基化碳纳米管(CNTs—COOH)、铅笔石墨(PGr)、聚吡咯(PPy)为原料,通过真空抽滤、涂覆、氧化聚合等方法,同时基于氢键界面相互作用的原理,制备出具有石墨层结构的CNF-CNTs—COOH-PGr/PPy柔性电极复合材料。结果表明,CNF-CNTs—COOH-PGr/PPy柔性电极复合材料在平直、折叠和拉伸时不会断裂,展现出较强的力学性能,其拉伸强度达到28.90 MPa。亲水性CNF与CNTs—COOH构筑的多孔结构增强了离子和电子的扩散路径。PGr的加入有效增加了CNF-CNTs—COOH-PGr/PPy柔性电极复合材料的导电路径,赋予其优良的导电性能。氧化聚合后得到的CNF-CNTs—COOH-PGr/PPy柔性电极复合材料的电导率达到5.403 S·cm?1。在1 mol·L?1 H₂SO₄溶液中,0.5 A·g?1电流密度下,CNF-CNTs—COOH-PGr/PPy柔性电极复合材料具有521 F·g?1的高比电容量,且经过1 500次充放电循环后,其电容保持率高达68%。基于柔性电极优良的力学性能、电化学性能和导电性能,CNF-CNTs—COOH-PGr/PPy柔性电极复合材料具备成为柔性储能器件电极材料的基本特性。      

碳布/聚吡咯储能包装膜材料的制备及表征

目的以甲壳素纳米纤维、多壁碳纳米管、碳布、吡咯为原料,制备柔性超级电容器复合电极薄膜。方法先利用化学氧化法提高碳布的表面粗糙度,再通过真空抽滤在碳布表面附着甲壳素纳米纤维和多壁碳纳米管,以增加碳布的负载空间,最后通过原位聚合吡咯来增加复合薄膜的电容性能。同时制备氧化碳布/聚吡咯复合薄膜作为对照组。结果制成的氧化碳布/甲壳素纳米纤维/多壁碳纳米管/聚吡咯复合薄膜在扫描速率为5 mV/s时,质量比电容达到了307 F/g,是氧化碳布/聚吡咯质量比电容(175 F/g)的1.75倍;在电流密度为2 A/g时,经过2000次循环后电容保留率为72.3%,库仑效率为73.8%。结论制备的氧化碳布/甲壳素纳米纤维/多壁碳纳米管/聚吡咯薄膜具有较高的比电容和循环稳定性,可以作为超级电容器电极材料应用于物联网行业的有源储能包装。     

聚乙烯醇-聚吡咯复合纳米纤维的制备及其导电性能

利用化学氧化法制备出导电聚吡咯（PPy）,与聚乙烯醇（PVA）共混后,采用静电纺丝技术制备PVA-PPy纳米共混纤维,随后加入对甲苯磺酸钠（TSNa）、十二烷基磺酸钠（DSNa）、十二烷基苯磺酸钠（DBSNa）和磺基琥珀酸二乙基己酯钠（DEHS）等不同掺杂剂改变纤维的结构和性能,采用SEM、TGA和四探针测试仪检测了纳米纤维的形貌、热稳定性和导电性能。结果表明,掺杂剂、PPy制备技术及聚合物添加剂对PPy的形貌、热稳定性和导电性能有很大影响。纳米纤维的电导率远远高于用同样掺杂剂所制备的PVA-PPy薄膜和PPy粉末,四种纳米纤维中DEHS掺杂PVA-PPy纳米纤维的电导率最高,可达26.64 S/cm。     

导电聚吡咯/醋酸纤维素复合膜的合成及性能研究

采用相分离原位聚合法在醋酸纤维素(CA)基体中合成聚吡咯(PPy),可制成均匀的PPy/CA导电复合薄膜,成膜后朝向玻璃的膜面(反面)是绝缘的,而朝向溶液的膜面(正面)却是导电的.膜中吡咯/醋酸纤维素的投料比为0.091时,导电复合膜的表面电阻约为20Ω/cm.通过红外光谱(FTIR)、原子力显微镜(AFM)对导电复合膜两面的化学组成、表面形态进行了表征.分析了制备条件对PPy/CA复合膜导电性能的影响.     

聚吡咯纳米管/碳纳米管复合材料在氧化还原电解液中的电化学性能

用模板法制备聚吡咯纳米管(PPyNTs),然后采用乙醇混合法将其和多壁碳纳米管(MWCNTs)制备了复合电极材料(PM)。比较不同材料在传统H_2SO_4电解液和添加了具有氧化还原活性物质胭脂红(AR18)的电解液中的电化学性能。三电极测试结果表明,在H_2SO_4电解液中PPy纳米颗粒的比电容为220 F/g,在氧化还原电解液中,PPyNTs的比电容为579.2 F/g,高于PPy纳米颗粒(445 F/g),而PM复合材料的最高比电容可达674.2 F/g,既高于单一PPyNTs又高于MWCNTs的(405.8 F/g)。利用性能优化的PM-3复合材料组装对称电容器,当电流密度为0.5 A/g时,功率密度为300 W/kg,能量密度达15.7 Wh/kg,且经过5000次循环,电容保持率为90%。说明AR18和H_2SO_4构建的氧化还原电解液能够提供额外的氧化还原反应,使具有双电层电容和赝电容的复合材料具有更加优良的电化学性能。     

共轭导电高分子/纳米纤维素复合材料研究进展

以纳米纤维素为基体材料、共轭导电高分子为功能材料,制备的共轭导电高分子/纳米纤维素复合材料兼具共轭导电高分子良好的导电性能以及纳米纤维素易改性、易成膜、可降解等优良特性,由此而拓宽了二者的开发与应用范围,并促进了导电高分子复合材料的发展。综述了几种典型的共轭导电高分子/纳米纤维素复合材料的研究进展,介绍了聚苯胺/纳米纤维素复合材料、聚吡咯/纳米纤维素复合材料和聚噻吩/纳米纤维素复合材料的制备及应用。     

片状聚吡咯/氧化石墨烯复合材料的制备及电化学性能

通过原位聚合在低温条件下(-10℃)制备具有片状微结构的聚吡咯(PPy)/氧化石墨烯(GO)复合材料,利用傅里叶红外光谱仪(FT-IR),扫描电子显微镜(SEM)对复合材料进行结构表征的基础上,利用循环伏安(CV)、恒流充放电(GC)、电化学阻抗技术(EIS)测试复合材料的电化学性能。FT-IR结果表明复合材料中GO与PPy存在相互作用;SEM结果表明复合材料显示为亚微米片状结构形貌;CV、GC、EIS电化学分析表明,与纯聚吡咯及氧化石墨烯相比,复合材料显示出优越的电容特性。当电流密度保持在1 A/g时,复合材料的比电容可达319 F/g,比GO(9 F/g)和PPy(167 F/g)的比电容都要高,该复合材料可用作潜在的超级电容器电极材料。     

静电纺定向纳米纤维素-碳纳米管/聚乙烯醇复合纤维导电膜及性能

利用纤维素纳米晶须（CNCs）搭载碳纳米管（CNTs）在水相中形成均一稳定的纳米CNCs-CNTs导电复合物,并将其均匀分散于聚乙烯醇（PVA）基体中制得纺丝液,采用静电纺丝技术制备纤维定向排列的CNCs-CNTs/PVA复合导电膜。结果表明：CNCs-CNTs增强了纤维膜热力学性能,并赋予其导电功能;纤维的定向排列显著提高了膜的力学性能;随CNTs含量增加,纺丝液电导率和黏度提高,纤维直径减小;当CNCs和CNTs与PVA的质量比分别为8.0%和1.0%时,CNCs-CNTs/PVA的纤维直径、拉伸强度和电导率分别可达182 nm±35 nm、15.99 MPa±1.25 MPa和0.12 S/m±0.01 S/m;当电流密度为0.2 A/g时,其比电容可达127.1 F/g,且经过1 500次充放电循环后电容量仍保持在83.14%。基于导电膜优良的力学性能、热稳定性和导电性,CNCs-CNTs/PVA导电膜有望应用于可折叠超级电容器、柔性传感器和柔性电极材料等领域。     

Enhanced electrical conductivity of polypyrrole/polypyrrole coated short nylon fiber/natural rubber composites prepared by in situ polymerization in latex

In this paper we report the characterization and properties of conductive elastomeric composites of polypyrrole (PPy) and PPy coated short Nylon-6 fiber (F-PPy) based on natural rubber (NR) prepared by in situ polymerization method. PPy/NR blends were prepared by polymerizing pyrrole in NR latex using anhydrous ferric chloride as oxidizing agent, p-toluene sulphonic acid as dopant and vulcastab VL as stabilizer. PPy/F-PPy/NR composites were prepared as above in presence of short nylon fiber. The products were coagulated out, dried, compounded on a two roll mill and moulded. The cure pattern, DC electrical conductivity, morphology, mechanical properties, thermal degradation parameters and microwave characteristics of the resulting composites were studied. Incorporation of PPy to elastomer retards the cure reaction whereas addition of fiber accelerates the cure reaction. DC conductivity up to 6.25 × 10⁻² was attained for NR/PPy/F-PPy system. The composites containing F-PPy exhibited better mechanical properties compared to NR/PPy systems. The absolute value of the dielectric permittivity, AC conductivity and absorption coefficient of the conducting composites prepared were found to be much greater than the gum vulcanizate. PPy and F-PPy were found to decrease the dielectric heating coefficient and skin depth significantly.     

Preparation and characterization of novel polypyrrole-nanotube/polyaniline free-standing composite films via facile solvent-evaporation method

Polyaniline (PANI) is an important conducting polymer and has drawn much attention for its inexpensiveness and chemical stability in the conducting state but its conductivity is rather low. Another well-known conducting polymer is polypyrrole (PPy) with a much higher electrical conductivity but it is hard to prepare films using PPy alone due to its poor film-forming ability. In this work, novel polypyrrole-nanotube (PPy-NT)/polyaniline (PANI) composite films are prepared via a facile solvent-evaporation method. The influence of the PPy-NT content is examined on the film structure, morphology, electrical and mechanical properties. It is shown that PPy nanotubes (PPy-NTs) are uniformly distributed in the PANI matrix. The electrical conductivity is greatly enhanced by 10.2 times by the addition of 10 wt.% PPy nanotubes. Moreover, the mechanical ductility is significantly increased by the addition of PPy nanotubes.     

PPy/graphene nanosheets/rare earth ions: A new composite electrode material for supercapacitor

Highly conductive PPy/graphene nanosheets/rare earth ions (PPy/GNS/RE³⁺) composites were prepared via in situ polymerization with p-toluenesulfonic acid as a dopant and FeCl₃ as an oxidant. The effects of GNS and RE³⁺ on the electrical conductivity of the composites were investigated. The results showed that the GNS as a filler had effect on the conductivity of PPy/GNS/RE³⁺ composites, which played an important role in forming a conducting network in PPy matrix. The microstructures of GNS and PPy/GNS/RE³⁺ were characterized by the SEM and TEM examinations. It was found that GNS and PPy nanospheres formed a uniform composite with the PPy nanospheres absorbed on the GNS surface and/or filled between the GNS. Such uniform structure together with the observed high conductivities afforded high specific capacitance when used as supercapacitor electrodes. A specific capacitance of as high as 238 F/g at a current density of 1 A/g was achieved over the PPy/GNS/Eu³⁺ composite.     

Conductive rubber composites from different blends of ethylene-propylene-diene rubber and nitrile rubber

Conductive rubber composites were derived from different blends of ethylene-propylene-diene monomer (EPDM) rubber and acrylonitrile butadiene rubber (NBR) containing acetylene black. The electrical and mechanical properties of these composites were measured. The percolation limit for achieving high conductivity of conductive filler depends on the viscosity of the blend. The higher the viscosity, the higher is the percolation limit. The conductivity rises with increasing temperature, and the activation energy of conduction increases with the decrease in the loading of conductive filler and percentage of NBR in the blend. Electrical hysteresis and an electrical resistivity difference during the heating-cooling cycle are observed for these systems, which is mainly due to some kind of irreversible change occurring in the conductive networks during heating. The mechanisms of conduction of these systems were discussed in the light of different theories. It was found that the degree of reinforcement by acetylene black in blends compares with those in the pure components NBR and EPDM. This is due to incompatibility of two elastomers in the blend. This revised version was published online in November 2006 with corrections to the Cover Date.     

导电硅橡胶泡沫材料的制备与性能研究

在硅橡胶基体中添加碳系导电填料(CB、CNT),利用超临界CO2发泡技术,制备了CB/硅橡胶、CNT/硅橡胶以及CB/CNT/硅橡胶复合导电泡沫材料,研究了混料胶料的流变行为以及发泡前后复合材料电导率、电磁屏蔽效能的变化规律。结果表明,CB与CNT均会阻碍硅橡胶复合材料的初始交联,导电填料含量越多交联越迟缓。CB/CNT/硅橡胶复配体系中更容易形成导电通路,当CB/CNT(1∶1)总含量为8%(质量分数)时,硅橡胶复合材料的电导率可达10^-5 S/cm,其电磁屏蔽效能(EI)为14~26 dB。发泡后,硅橡胶复合材料的电导率及EI值均有所下降。     

锂离子电池硅/碳纳米管/石墨烯自支撑负极材料研究

通过真空驱动自组装法及蒸汽处理得到结构疏松的硅/碳纳米管/石墨烯自支撑负极材料(Si/CNTs/GP)。纳米硅颗粒(50 nm)为活性物质, 均匀分布在石墨烯片层结构中间; 石墨烯作为碳基体, 通过自组装构筑形成二维导电网络; 碳纳米管(CNTs)具有超高导电性和良好的力学强度, 它通过吸附作用均匀分布在石墨烯基体上形成导电的支撑网络结构。经过蒸汽处理后, 石墨烯层间距明显增大, 层与层之间不再是紧密堆叠的结构, 而是形成一种疏松、褶皱、内部空隙丰富的片层结构。Si/CNTs/GP负极材料中丰富的内部空穴和贯穿孔洞, 提供了材料很高的比表面积, 能有效提高电解液对材料的浸润性, 极大缩短了离子传输距离。同时这些内部空穴也有效缓冲硅充放电时的体积膨胀, 提高了材料的结构稳定性和电化学性能。该负极材料在4 A/g的大电流密度下容量维持在600 mAh/g, 表现出良好的大电流循环稳定性能。     

橡胶分子链接枝对导电炭黑/天然橡胶复合材料电磁性能的影响

采用乳液法制备了聚甲基丙烯酸甲酯接枝改性的天然橡胶(MNR),并通过机械共混法制备了其与导电炭黑(CCB)的复合材料,研究了橡胶分子链接枝改性对复合材料微观结构和电磁性能的影响。研究结果表明,与天然橡胶(NR)相比,CCB会在MNR中选择性偏聚,形成更完善的填料损耗网络,进而改善复合材料的电磁性能。复合材料电磁性能随着CCB含量的增加而增加,当CCB含量为30phr时,复合材料的电导率、介电损耗因子、反射损耗达到峰值,分别为0.75S/m、0.34、-22.38dB,依次为CCB/NR复合材料的2.18倍、1.48倍和2.15倍;基于微相分离,讨论了复合材料对电磁波的衰减机理。     

Surface modification of carbon nanofibers by glycidoxysilane for altering the conductive and mechanical properties of epoxy composites

Carbon nanofibers (CNFs) were functionalized with 3-glycidoxypropyltrimethoxysilane and dispersed into epoxy resin. The chemical modification of CNFs was confirmed by FTIR, SEM, EDX and TGA measurements. After silanization, FTIR showed the existance of epoxy ring; EDX detected Si element; while TGA indicated 1.1 wt.% Si on CNFs. Mechanical properties were analyzed by DMA. Silanized CNFs/epoxy composites demonstrated improved dispersion of CNFs in the matrix, and an enhancement of storage modulus for about 20% compared to the neat matrix, which indicated that the modification of CNFs improved the adhesion between fillers and matrices. DC electrical conductivity of CNFs was reduced about 7-fold compared to the original CNFs due to the silane coating. Accordingly, the composites containing silanized CNFs also had lower electrical conductivity than those containing original CNFs. In spite of decreased electrical conductivity, thermal conductivity of silanized CNFs/epoxy composites was increased due to the surface modification of CNFs.