尼龙1010/蒙脱土纳米复合材料的合成与表征

通过插层聚合制备了尼龙1010／蒙脱土纳米复合材料，测试了材料的力学性能，耐溶剂性，并通过SEM，WAXD，DSC等分析手段，研究了蒙脱土在聚合物基体中的分散情况及聚合物的结晶行为。实验结果表明，通过单体插层聚合方法所制得的复合物，其性能较尼龙1010有较大提高，蒙脱土在聚合物中基本达到了纳米级分散。     

原位聚合制备尼龙6/多壁碳纳米管复合材料及性能表征

用原位聚合法制备了尼龙6/多壁碳纳米管(MWCNTs)复合材料。先对多壁碳纳米管进行胺基功能化处理,再研究了多壁碳纳米管添加量对复合材料电性能和力学性能的影响,结果显示,复合材料体积电阻率和表面电阻率相对于不加碳纳米管制得的尼龙6基体降低了3个数量级,复合材料的介电常数显著增加,相对于不加碳纳米管的增加了71%;复合材料的弹性模量、弯曲模量、弯曲强度随碳纳米管加入量的增加大幅提高。     

纳米银/PAMPS复合物的微波合成及表征

在不加还原剂的条件下,微波辐射双原位合成纳米银/2-丙烯酰胺基-2-甲基丙磺酸均聚物[PAMPS]复合材料。并通过UV-Vis、XRD、FTIR、TEM、XPS和TG等分析方法对其进行表征。结果表明:纳米银粒子具有面心立方结构,且较均匀地分散在聚合物基体中;微波辐射时间不影响纳米银粒子的形态;纳米银与基体PAMPS中的氮原子和羰基氧原子存在相互作用,而且对基体PAMPS的热学性能有很大影响。     

尼龙1010与壳聚糖共混膜的制备、表征及性能研究

用红外光谱,X射线衍射,差示扫描量热,扫描电镜,吸水率,力学性能及降解性能测试对尼龙1010与壳聚糖共混膜进行了表征。结果表明,共混膜中,当尼龙1010含量不超过80％时,尼龙1010分子链与壳降糖分子链在晶区有一定相互作用,但在非晶区是不相容的,共混膜呈现出明显的“海－岛”结构。壳聚糖的引入有利于改善尼龙1010的力学性能及生物降解性能,降低其吸水性。     

尼龙1010/白炭黑纳米复合材料的研究进展

介绍了白炭黑的结构性能、制备方法、表面改性及尼龙1010/白炭黑纳米复合材料的制备方法;指出与纯尼龙1010相比,尼龙1010/白炭黑纳米复合材料具有良好的机械性能和加工性能,应用前景广阔.     

功能化碳纳米管的制备及功能化碳纳米管/尼龙6复合纤维

采用多聚磷酸(PPA)/P₂O₅弱酸体系, 通过傅克反应(Friedel-Crafts reaction)对多壁碳纳米管(MWCNTs)进行功能化改性, 加入己内酰胺后采用原位聚合法制备功能化碳纳米管(F-MWCNTs)/尼龙6(PA6)复合材料, 并熔融纺丝制备复合纤维。通过TEM、TG、DSC、SEM及力学性能测试对复合纤维进行表征。结果表明: 在MWCNTs表面成功地接枝了氨基, F-MWCNTs均匀地分散在PA6基体中, 没有发生团聚现象, 并且与基体具有很好的界面作用; F-MWCNTs的加入, 对复合纤维的熔融温度和结晶度影响不大, 结晶温度有所提高, 并明显提高了复合纤维的热稳定性; 随着F-MWCNTs的加入, 复合纤维的拉伸断裂强度和杨氏模量增加, 当F-MWCNTs质量分数为0.5%时, 拉伸断裂强度和杨氏模量达到最大, 比纯PA6纤维分别提高了45%和208%。     

PA6-66-1010/MCPA6复合材料的结构与性能

采用原位聚合法制备了三元共聚尼龙6-66-1010(PA6-66-1010)与原位浇铸尼龙6(MCPA6)的共混复合材料。利用差示扫描量热法(DSC)、动态热机械分析(DMA)、力学性能测试和扫描电子显微镜(SEM)表征复合材料的结晶熔融行为、动态力学性能、力学性能及断裂破坏形貌。结果表明,PA6-66-1010的加入,使得复合材料中MCPA6分子间的氢键作用减弱、分子链活动性增加;复合材料的结晶温度、熔融温度、结晶度随着PA6-66-1010含量的增加而下降;PA6-66-1010的加入,破坏了MCPA6分子间氢键的规整性,使得复合材料韧性得到提高而强度变化不大;当PA6-66-1010含量为10%时,复合材料断裂伸长率提高近6倍。     

碳纳米管/聚苯胺复合材料的制备及电性能

利用超声波将多壁碳纳米管(CNTs)分散于苯胺盐酸溶液体系中,以过硫酸铵((NH4)2S2O8)为氧化剂,原位聚合法制备碳纳米管/聚苯胺纳米复合材料(CNTs/PANI)。采用扫描电子显微镜(SEM)、傅立叶变换红外光谱(FT-IR)、四探针电导率测试仪对复合材料进行表面观察、结构测定和电性能表征。结果表明,复合材料为核-壳结构,碳纳米管和聚苯胺间存在相互作用,其电导率随碳纳米管含量的增加而增加。     

聚苯胺/碳纳米管的原位复合

通过原位溶液聚合制备了聚苯胺/碳纳米管(PANI/CNT)复合材料。采用透射电子显微镜(TEM)、紫外-可见光光谱(UV-VIS)、傅立叶变换红外光谱(FTIR)、热失重分析(TGA)及差示扫描量热法(DSC)研究了PANI/CNT复合材料的结构与性能。研究表明,苯胺(ANI)的聚合倾向于在碳纳米管(CNT)表面进行,形成PANI包覆的CNT。CNT表面PANI层的厚度随溶液中ANI含量的增加而增加;当溶液中ANI含量较低时,CNT表面PANI层厚度均匀;当ANI含量过高时,CNT表面PANI层厚度不均匀,形成一些颗粒状附着物。PANI与CNT之间主要是物理吸附;PANI/CNT复合材料的电导率远高于PANI本身。同时,PANI/CNT复合材料的耐热性远高于PANI,并受PANI含量影响。     

抗粘、耐磨、耐蚀火焰喷涂尼龙1010/石墨复合涂层

对火争喷涂尼龙１０１０／石墨复合涂层的抗粘、耐磨及耐蚀性能进行了研究。结果表明,该复合涂层较纯尼龙涂层具有更加优异的耐磨及耐蚀减摩性有和较好的抗抗粘性能。通过室温浸泡蚀性能测定,该涂层具有与整体尼龙相当的耐蚀性能。     

Fracture behavior of nylon hybrid composites

Hybrid composite systems consisting of liquid crystalline polymer (LCP), short glass fibers and toughened nylon in varied ratios were studied. Dynamic mechanical results indicated that, elastomeric phase in toughened nylon 6,6 promoted a better compatibilization between nylon 6,6 and LCP in a hybrid system containing short glass fibers in comparison with one without glass fibers. Improved compatibility facilitated fibrillation of LCP phase in the skin region of the hybrid composite, thereby providing superior tensile strength. Without the presence of LCP, glass fiber reinforced toughened nylon 6,6 exhibited the least tensile strength. J-integral analysis and essential work of fracture (EWF) method were used to compare the fracture behavior of composites. Results showed that specific essential work of fracture were consistent with the critical J-integral. Matrices reinforced by LCP alone showed the best crack initiation and propagation toughnesses, followed by glass fiber reinforced and hybrid composites. The better compatibility between nylon 6,6 and LCP appeared to inhibit the interfacial debonding process, resulting in brittle fracture.     

聚乙二醇-碳纳米管(PEG-CNTs)共聚物膜的制备及其微摩擦行为的研究

制备了聚乙二醇接枝碳纳管共聚物(PEG-CNTs)。通过红外光谱(FT-IR)。荧光光谱(FS)和透射电子显微镜(TEM)对共聚物进行了表征。利用旋涂技术以云母为基片制备了共聚物薄膜,采用原子力显微镜／摩擦力显微镜(AFM／FFM)研究了薄膜表面的形貌及微摩擦学行为。复合薄膜内的聚合物组分保证了膜的表面平整,坚硬的碳纳米管组分增强了薄膜的承载能力。     

碳纳米管/聚苯胺复合物的制备及其吸波性能的研究

采用原位聚合法制备碳纳米管/聚苯胺复合物,并通过透射电镜(TEM)、红外光谱(FT-IR)、热重分析(TGA)对样品进行表征,用矢量网络分析仪系统检测了一系列复合物的电磁参数,计算并分析了聚合时间、聚合温度、盐酸浓度、涂层厚度等工艺条件对复合物吸波性能的影响。结果表明,原位聚合法制得了具有核-壳结构的复合物;且聚合时间为6 h、聚合温度为20℃、盐酸浓度为0.05 mol/L时,复合物在8~18 GHz频率范围内具有较好的微波吸收性能。     

Impact behavior and fractographic study of carbon nanotubes grafted carbon fiber-reinforced epoxy matrix multi-scale hybrid composites

Carbon nanotubes are the most promising reinforcement for high performance composites. Multiwall carbon nanotubes were directly grown onto the carbon fiber surface by catalytic thermal chemical vapor deposition technique. Multi-scale hybrid composites were fabricated using the carbon nanotubes grown fibers with epoxy matrix. Morphology of the grown carbon nanotubes was investigated using field emission scanning electron microscopy and transmission electron microscopy. The fabricated composites were subjected to impact tests which showed 48.7% and 42.2% higher energy absorption in Charpy and Izod impact tests respectively. Fractographic analysis of the impact tested specimens revealed the presence of carbon nanotubes both at the fiber surface and within the matrix which explained the reason for improved energy absorption capability of these composites. Carbon nanotubes presence at various cracks formed during loading provided a direct evidence of micro crack bridging. Thus the enhanced fracture strength of these composites is attributed to stronger fiber–matrix interfacial bonding and simultaneous matrix strengthening due to the grown carbon nanotubes.     

Curing behavior and kinetic analysis of epoxy resin/multi-walled carbon nanotubes composites

The effect of multi-walled carbon nanotubes (MWNTs), both amino-functionalized (f-MWNTs) and unfunctionalized (p-MWNTs) on the curing behavior of epoxy resin (EP) cured with triethanolamine (TEA), was investigated using differential scanning calorimetry (DSC). Because the triethylenetetramine (TETA) grafted on the f-MWNTs could act as curing agent and the produced tertiary amine as negative ionic catalysts of curing reaction of EP, so the activation energy of the EP/TEA system was decreased by the addition of f-MWNTs. Viscosity played a key role in the curing behavior of the EP/TEA/MWNTs system, for high viscosity of the EP/TEA/MWNTs system could hinder the motion of the functional groups. The curing heat in EP/TEA/f-MWNTs (weight ratio 1/0.1/0.01) system was higher than the neat EP/TEA (weight ratio 1/0.1) system, while the curing heat in EP/TEA/p-MWNTs (weight ratio 1/0.1/0.01) was lower than the neat system. When the content of f-MWNTs was increased to 2 phr (weight ratio of 1/0.1/0.02), the curing heat became lower than that of the neat EP/TEA system, which was the result of the higher viscosity of the EP/f-MWNTs/TEA system. Since the curing heat indicated the curing degree of the system generally, the addition of the f-MWNTs was thought to increase the curing degree of the epoxy matrix at a relatively low content.     

Influence of carbon nanotubes structure on the mechanical behavior of cement composites

Cement matrix composites have been prepared by adding 0.5% in weight of multi wall carbon nanotubes (MWCNTs) to plain cement paste. In order to study how the chemical–physical properties of the nanotubes can affect the mechanical behavior of the composite, we compared the specimen obtained by mixing the same cement paste with three different kinds of MWCNTs. In particular, as-grown, annealed and carboxyl functionalized MWCNTs have been used. In fact, while high temperature annealing treatments remove lattice defects from the walls of CNTs, hence improving their mechanical strength, acid oxidative treatments increase chemical reactivity of pristine material, consequently chemical bonds between the reinforcement and the cement matrix are supposed to enhance the mechanical strength.Flexural and compressive tests showed a worsening in mechanical properties with functionalized MWCNTs, while a significant improvement is obtained with both as-grown and annealed MWCNTs.The phase composition of the composites was characterized by means of thermo gravimetric analysis coupled with mass spectroscopy, while the mineralogy and microstructure were analyzed by means of an X-ray diffractometer and scanning electron microscope. The results are interpreted and discussed taking into account the chemical and physical properties of the MWCNTs by means of EDX, TGA, SEM and Raman analysis.     

Thermal stability of carbon-MoSi2-carbon composites by thermogravimetric analysis

A thermal stability of carbon-carbon composites with increase of oxidation resistant filler, MoSi₂, have been studied by thermogravimetric analysis during the graphitization process. In this work, the initial decomposition temperature, temperature of maximum rate of weight loss, integral procedure decomposition temperature, and decomposition temperature range for the degradation temperatures, and the activation energy based on Horowitz-Metzger calculating method were characterized in a thermal stability study. It has been found that 12–20 wt% filler on the basis of the resin matrix leads to an improvement of degradation temperature and to an effectively increase of activation energy of the composites. This is probably due to the effect of the inherent MoSi₂ properties, resulted from a brittle-to-ductile transition for increasing the interfacial adhesion between fiber and matrix, and a mobile diffusion barrier formation against oxygen attack, in the vicinity of 900–1000°C.     

Synthesis of polyoxometalates-functionalized carbon nanotubes composites and relevant electrochemical properties study

Carbon nanotubes (CNTs)-based polyoxometalates (POMs)-functionalized nanocomposites were synthesized by simply functionalizing CNTs with Keggin and Dawson-type POMs. The positively charged polyelectrolyte poly (diallyldimethylammonium chloride) (PDDA) was introduced to assemble negatively charged POMs and CNTs. The composition, structure and morphology were investigated by UV-visible (UV-vis), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Cyclic voltammetry (CV) was employed to investigate the electrochemical properties of the resulting nanocomposites. The cyclic voltammograms indicate that the electrochemical properties of POMs are fully maintained. Functionalizing CNTs with POMs not only retains the unique properties of nanotubes, but also endows CNTs with the reversible redox activity of POMs.