聚合物对多壁碳纳米管的包覆改性研究

探讨了聚合物对碳纳米管的包覆改性.将多壁碳纳米管(MWNTs)通过浓硫酸和浓硝酸的混酸(体积比=3∶1)处理,使其带上羧基.将羧化MWNTs与甲基丙烯酸缩水甘油酯(GMA),苯乙烯双组分接枝聚苯乙烯(PS-g-(GMA-co-St))通过溶液共混方法,使其接在MWNTs上的羧基和GMA所带的环氧基团之间发生酯化反应,实现MWNTs表面接枝上PS-g-(GMA-co-St).扫描电镜观察表明,羧化MWNTs平均管径约为40nm,而接枝上PS-g-(GMA-co-St)的改性MWNTs管径可达约100nm.用四氢呋喃(THF)对表层包覆的PS-g-(GMA-co-St)刻蚀后,其直径降回到约40nm,这和先前观察到的羧化MWNTs的直径基本一致.对刻蚀后的MWNTs样品的FT-IR分析也表明MWNTs表面上存在接枝PS.表面经过PS-g-(GMA-co-St)修饰后,可以形成包覆层,为MWNTs在聚合物基体中分散、制备纳米功能材料提供了途径.     

多壁碳纳米管/溴/聚苯乙炔三元复合材料导电性能的研究

通过机械共混和溶液共混制备了多壁碳纳米管(MWNTs)/溴/聚苯乙炔(PPA)三元复合材料, 复合材料表现出良好的导电性能, 电导率为10 S/m, 达到掺溴MWNTs的导电水平. 通过固体紫外光谱、XPS和SEM分析了复合材料中MWNTs、溴与PPA三者之间的相互作用, 研究了独立导电单元的形成, 以及导电单元对电导率提高所起的作用. 结果表明, 当MWNTs含量较低时, MWNTs和PPA之间的溴转移导致复合材料电导率降低; MWNTs含量较高时, 独立导电单元的数目增多, 复合材料的电导率随之大幅提高.     

聚噻吩/多壁碳纳米管复合材料的导电性能

通过共混多壁碳纳米管(MWNTs)和聚噻吩(PTh), 制备了PTh/MWNTs复合材料, 复合材料表现出良好的导电性能(电导率达16.1 S/m). 通过Raman, TG, XPS, UV-Vis等对复合材料进行了分析, 结果表明, MWNTs和 PTh之间存在强的相互作用, MWNTs上的离域电子与噻吩共轭主链上的π电子之间形成π-π共轭, 电子从MWNTs转移到聚噻吩, 增加了噻吩主链的有效共轭长度, 提高了复合材料的导电性能. FESEM分析表明, MWNTs和它周围被掺杂的聚噻吩通过π-π共轭作用结合在一起, 形成相对独立的导电单元, 在复合材料的导电体系中起到主要作用.     

多壁碳纳米管/溴/聚苯乙炔三元共混物导电性能的研究

通过机械共混和溶液共混制备了多壁碳纳米管(MWNTs)/溴/聚苯乙炔(PPA)三元复合材料,复合材料表现出良好的导电性能,电导率为10S/m,达到掺溴MWNTs的导电水平.通过固体紫外光谱、XPS和SEM分析了复合材料中MWNTs、溴与PPA三者之间的相互作用,研究了独立导电单元的形成,以及导电单元对电导率提高所起的作用.结果表明,当MWNTs含量较低时,MWNTs和PPA之间的溴转移导致复合材料电导率降低;MWNTs含量较高时,独立导电单元的数目增多,复合材料的电导率随之大幅提高.     

RuO2·χH2O/MWNTs纳米复合物的超级电容特性研究

本文采用超声波技术合成了水合氧化钉/多壁碳纳米管纳米复合材料(Ru-MWNTs)前驱物,在150℃下热处理15 h后得到Ru-MWNTs.采用XRD及TEM对纳米复合材料进行表征,结果表明,水合氧化钌以无定型态比较均匀地沉积在MWNTs上.在1.0 mol·L-1H2SO4电解液中对Ru-MWNTs复合电极进行了电化学测试,循环伏安结果表明纳米复合物具有良好的电容性能,其比容量为100 F·g-1,是MWNTs的6倍(MWNTs的比容量为15.5 F·g-1);本文还采用交流阻抗方法来分析频率与电容的关系,比较分析了MWNTs和复合材料的孔结构,表明在MWNTs中复合少量的水合氧化钌可以提高电极材料的充、放电速度.     

聚丙烯/多壁碳纳米管复合材料的热性能和流变性能

用熔融共混法制备了聚丙烯多壁碳纳米管(PP MWNTs)复合材料,TGA研究表明在氮气气氛下碳纳米管显著增加了聚丙烯基体的热稳定性.3wt%MWNTs可使PP热分解起始温度提高44℃.非等温结晶研究表明MWNTs对PP基体的结晶行为没有明显的影响.流变测试结果表明PP MWNTs复合材料的储能模量G′和损耗模量G″随着MWNTs含量增加逐渐增大.1wt%MWNTs的PP聚合物的零剪切粘度最低,5wt%MWNTs的PP聚合物的零剪切粘度最高,PP和3wt%MWNTs的PP纳米聚合物的零剪切粘度居于二者之间,随着频率的增加,剪切稀化作用越来越明显,呈现出假塑性流体行为.含5wt%MWNTs的PP复合材料的体积和表面电阻率与纯PP相比分别下降了9个和4个数量级,表明少量的MWNTs可以显著改变PP的电学性能.     

镍铁氧体/碳纳米管复合材料的制备及其对染料废水的吸附性能

用浸渍法制备了镍铁氧体/碳纳米管(NF/MWNTs)复合材料。用XRD、SEM、TEM、VSM、UV-Vis等表征了样品的组成、结构、形貌、磁性能和吸附性能。结果表明,制备的NF/MWNTs复合材料保留了碳纳米管优良的吸附性能,且具有良好的镍铁氧体负载率和优异的磁性能。质量比(mNF/mMWNTs)为1的NF/MWNTs复合材料对亚甲基蓝溶液的最大吸附容量为18.87 mg·g-1,其吸附行为符合Langmuir和Freundlich模型。NF/MWNTs复合材料对亚甲基蓝溶液的脱色率与溶液温度和pH值呈正相关性。此外,NF/MWNTs复合材料回收容易,活化处理简便,可重复使用。     

接枝聚苯乙烯/多壁碳纳米管纳米复合材料制备及合成机理

通过原位悬浮聚合的方法, 以过氧化苯甲酰(BPO)做引发剂, 制备了聚苯乙烯/多壁碳纳米管(MWNT-g-PS)纳米复合材料, 复合材料在水和乙醇中均表现出良好的分散性及稳定性. 通过高倍透射电镜(HRTEM)、场发射扫描电镜(FESEM)分析, 多壁碳纳米管上包覆有1～3 nm的聚苯乙烯膜, 并分布有半径从几十纳米到几百纳米不等的聚苯乙烯微球. 通过傅立叶变换红外光谱(FTIR)、拉曼光谱(Raman spectroscopy)、X光电子能谱(XPS)和热重分析(TGA)对复合材料进行分析, 结果表明, 自由基将多壁碳纳米管表面π键打开, 形成一种新的自由基, 引发聚苯乙烯的自由基聚合, 形成了接枝聚苯乙烯/多壁碳纳米管纳米复合材料.     

聚3-辛基噻吩/MWNTs复合材料的导电性能研究

采用在氯仿溶液中超声共混, 制备聚3-辛基噻吩(P3OT)和多壁碳纳米管(MWNTs)复合材料. 当MWNTs掺杂量为3%时复合材料的电导率为1.43 S•m－1, 达到纯MWNTs的电导率水平. 用FTIR光谱, TG, UV-Vis光谱, XPS和FESEM进行研究分析, 认为MWNTs的离域电子与P3OT主链上的π电子之间形成π-π共轭, 增加了P3OT主链的有效共轭度, 被掺杂的P3OT具有很高的电导率, 提高了复合材料的导电性能. MWNTs与被掺杂的P3OT组成相对独立的导体单元, 对复合材料的导电网络形成起着主要作用.     

聚噻吩/多壁碳纳米管复合材料结构与导电机理的研究

从结构和相互作用方面对聚噻吩(PTh)/多壁碳纳米管(MWNTs)复合材料进行了研究, 结果表明: 一方面聚噻吩本身的结构对其导电性能有一定的影响, 另一方面MWNTs作为一种掺杂剂, 和聚噻吩之间存在强的相互作用, 电子从MWNTs转移到聚噻吩. MWNTs和它周围被掺杂的聚噻吩通过π-π共轭作用形成相对独立的导电单元, 在复合材料的导电体系中起到主要作用, 随着这种导电单元数量的增加直至相互接触, 形成大的导电体系, 复合材料的电导率达到最大值.     

Bulk polymerized polystyrene in the presence of multiwalled carbon nanotubes

The in situ bulk polymerization method was applied to synthesize composites of multiwalled carbon nanotubes (MWNTs) and polystyrene (PS) under ultrasonication to open π-bonds in the MWNTs. Morphology of the composite products was studied by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Thermal properties and molecular weight of the PS synthesized in the presence of the MWNTs were examined by thermogravimetric analysis (TGA) and gel permeation chromatography (GPC), respectively. The MWNTs were observed to play an important role as initiator consumers during the polymerization reaction. Electrical conductivity of a film-type sample of the PS/MWNT nanocomposite was found to increase with increased amount of MWNTs added, following the percolation theory.     

高分子量聚苯胺/碳纳米管复合材料的合成与表征

在导电聚合物中,聚苯胺（PANI）因其导电性能优良,环境稳定性好,合成工艺简单,原料成本低廉等优点,被认为是最有可能实际应用的导电聚合物．然而用传统方法合成的聚苯胺由于其分子量小,分子链中存在缺陷而使其导电性能和力学性能大大降低,从而限制了其实际应用．而高分子量聚苯胺的导电性能和力学性能比一般聚苯胺有较大的提高．     

Synthesis and self‐assembly of polystyrene‐grafted multiwalled carbon nanotubes with a hairy‐rod nanostructure

Polystyrene‐grafted multiwalled carbon nanotubes (PS‐g‐MWNTs) with a hairy‐rod nanostructure were synthesized by the in situ free‐radical polymerization of styrene in the presence of multiwalled carbon nanotubes (MWNTs) terminated with vinyl groups. To quantitatively study the molecular weight and composition of polystyrene (PS) chains in PS‐g‐MWNTs, PS‐g‐MWNTs were fully defunctionalized by hydrolysis. The results showed that 1 of every 100 carbon atoms in MWNTs was functionalized at the tips and outer walls of the carbon nanotubes and grafted by PS with a weight‐average molecular weight of 9800 g/mol; therefore, a uniform thin layer (ca. 8–10 nm) of a PS shell was formed on the outer wall of MWNTs. PS‐g‐MWNTs were soluble in dimethylformamide and tetrahydrofuran. The thermal stability and glass‐transition temperature of PS in PS‐g‐MWNTs were obviously increased. Nanopins were formed on the glass substrates by the self‐assembly of PS‐g‐MWNTs, and the dewetting effect between the glass substrate and PS chains covered MWNTs during the evaporation of the solution. Both the length and diameter of the nanopins increased with the solution concentration. When PS‐g‐MWNTs were compression‐molded, MWNTs were dispersed uniformly in the PS matrix and formed good networks, such as circlelike and starlike structures, because of the entanglements of hairy PS chains on MWNTs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3869–3881, 2006     

聚(2,5-苯并(口恶)唑)/多壁碳纳米管复合材料的制备与性能

采用强氧化性酸处理多壁碳纳米管(MWNTs),形成功能化的多壁碳纳米管(MWNTs-COOH)。用傅里叶红外光谱(FT-IR)对处理前后MWNTs的表面官能团进行了分析,并利用原位聚合法成功制备了聚(2,5-苯并噁唑)(ABPBO)/MWNTs-COOH纳米复合材料。结果表明:碳纳米管经过酸处理后,表面含有较多羰基和羟基极性官能团,在ABPBO基体中分散均匀;复合材料保持了ABPBO的优异耐高温性能,其力学性能和光物理性能也得到了很大的提高。     

Effect of polymerization conditions on the molecular weight of polystyrene grafted onto silica in the radical graft polymerization initiated by azo or peroxyester groups introduced onto the surface

The effect of polymerization conditions on the molecular weight of polystyrene grafted onto silica obtained from the radical graft polymerization initiated by azo and peroxyester groups introduced onto the surface was investigated. The molecular weight of polystyrene grafted onto silica obtained from the radical graft polymerization initiated by surface azo and peroxyester groups decreased with decreasing monomer concentration and polymerization temperature. The molecular weight of polystyrene was found to be controlled to some extent by the addition of a chain transfer agent. The molecular weight of grafted chain on silica surface obtained from the graft polymerization initiated by surface radicals formed by photodecomposition of azo groups was considerably smaller than that by thermal decomposition. The number of grafted polystyrene in photopolymeriztion, however, was much larger than that in thermal polymerization. These results are explained by the blocking of surface radicals formed on the silica surface by previously grafted polymer chain: when the decomposition of surface azo and peroxyester groups proceed instantaneously at the initial stage of the polymerization, the number of grafted polymer chains increased.     

原位缩聚法制备碳纳米管/尼龙11复合材料

用原位缩聚法制备了碳纳米管增强的尼龙11复合材料,用X射线衍射仪、红外(FTIR)、扫描电镜(SEM)、热重(TGA)、机械拉伸测试仪等对其结构、形貌、热性能及机械性能进行了表征测试.扫描电镜结果显示碳纳米管均一地分散在尼龙11/碳纳米管复合材料中.复合材料的拉伸模量比纯尼龙11有较大的提高.当复合材料中碳纳米管含量分别为1%,5%,10%时,材料的拉伸模量分别提高了34.5%,92.9%和113,7%.同时,复合材料的储能模量也有提高.热分析结果显示当复合材料中碳纳米管含量为1%时,其失重5%和10%的温度分别由纯尼龙11的404℃、424℃提高到414℃和437℃.示差扫描量热分析(DSC)显示复合材料的结晶温度随碳纳米管的加入而升高,而结晶度则降低.     

Influence of silver-decorated multi-walled carbon nanotubes on electrochemical performance of polyaniline-based electrodes

In this work, silver (Ag) nanoparticles were deposited on multi-walled carbon nanotubes (MWNTs) by chemical reduction while Ag-decorated MWNTs (Ag-MWNTs)/polyaniline (PANI) composites were prepared by oxidation polymerization. The effect of the Ag incorporated into the interface of the composites on the electrochemical performance of the MWNTs/PANI was investigated. It was found that highly dispersed Ag nanoparticles were deposited onto the MWNTs, and the Ag-MWNTs were successfully coated by PANI. According to cyclic voltammograms, the Ag-MWNTs/PANI exhibited significantly increased electrochemical performances compared to MWNTs/PANI and the highest specific capacitance obtained of MWNTs/PANI and 0.15 M Ag-MWNTs/PANI was 162 F/g and 205 F/g, respectively. This indicated that Ag nanoparticles that were deposited onto the MWNTs caused an enhanced electrochemical performance of the MWNTs/PANI due to their high electric conductivity, which resulted in an increase of the charge transfer between the MWNTs and PANI by a bridge effect.     

Polystyrene-coated micro-sized particles by "in situ" surface initiated polymerization in accord with Langmuir model adsorption

This study describes the mechanism of adsorption of polystyrene chains PS "in situ" growth from micro-sized commercial silicate particles, i.e. Feldspar. The main aim is to derive adsorption isotherms from thermal gravimetric analysis (TGA) and size exclusion chromatography (SEC) data obtained during the direct polymerization of PS initiated by a pre-adsorbed radical initiator onto the inorganic surface. The adsorption isotherm plot indicates that the PS adsorption is in accord with the Langmuir Model. The amount of PS monolayer coverage increases with polymerization time, and it is highly dependent on the monomer diffusion to the surface during the hybrid inorganic/organic synthesis. Such behavior depends on the concentration gradient between monomer concentration in solution and that adsorbed by polymerization onto the micro-sized particles surface of Feldspar.     

PS/MWNT复合材料界面上的化学反应性

利用悬浮聚合法制备了可溶于甲苯的聚苯乙烯／多壁碳纳米管（PS／MWNT）复合材料,通过透射电镜观察到MWNT完全或部分被PS包裹。拉曼光谱分析表明,复合材料中MWNT的两个特征峰D峰和G峰的位置均发生了红移,且D峰的强度及ID／IG值也较MWNT明显增大。凝胶渗透色谱测得复合材料的分子量相对于纯PS的分子量有较大幅度提高。同时比较共混法与悬浮聚合法制得的复合材料在甲苯中的溶解性。可以认为悬浮聚合法制备复合材料的过程中,MWNT参与了PS的聚合反应,与PS形成了化学键从而完全或部分地被PS包裹。     

PLA/MWNTs/HA复合材料的制备和性能研究

采用超声辅助原位湿法合成多壁碳纳米管／羟基磷灰石纳米复合材料(MWNTs／HA),并通过溶液浇铸法制备了PLA／MWNTs／HA复合材料薄膜。考察了MWNTs／HA纳米粒子含量对复合膜性能的影响,并通过力学性能、SEM、FTIR、以及DMTA对复合膜性能进行了表征,结果表明：随着纳米粒子质量分数的增加,复合膜的拉伸强度呈下降趋势;拉伸模量和储能模量呈现先下降后上升的趋势;玻璃化转变温度则呈现不断上升趋势。