外贴Fe3O4/CNTs杂化碳纳米纸的碳纳米管复合材料吸波性能

通过对Fe₃O₄纳米粒子接枝碳纳米管的单分散水溶液真空吸滤制备出一种新型的杂化碳纳米纸, 它与树脂浸润良好, 可以与复合材料一体成型。分别借助FE-SEM、EDS、BJH法和振动样品磁强计表征杂化碳纳米纸及其复合材料的微观形貌、元素组成、平均孔径分布和磁性能。在8.2~18 GHz频段内利用波导法测量碳纳米管共混复合材料和外贴杂化碳纳米纸/碳纳米管共混复合材料的电磁参数和吸波反射率。研究结果表明: 外贴一层杂化碳纳米纸(厚0.1 mm)后, 碳纳米管共混复合材料的磁损耗明显增加, 在8.2~18 GHz微波频段内吸波反射率基本上全部小于-10 dB(频宽大于9.7 GHz), 在15.42 GHz位置, 反射损耗峰达-43.18 dB, 远优于碳纳米管共混复合材料。     

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。     

碳纳米管/纳米铁颗粒杂化结构的制备及形成机理

采用催化化学气相沉积法将由C包覆的纳米铁颗粒(FeNP)原位沉积于碳纳米管(CNTs)表面并形成不同形貌的碳纳米管/纳米铁颗粒(CNTs/FeNP)杂化结构。使用扫描电子显微镜、透射电子显微镜对制备的杂化结构进行微观形貌分析和结构表征。结果显示,纳米铁颗粒通过石墨片层结构与碳纳米管相连,具有良好的界面结合。当噻吩的添加量较低时,产物中碳纳米管的直径减小,产量增多。当噻吩的添加量超过0.5%时,可以得到CNTs/FeNP杂化结构。使用X射线能谱仪、X射线衍射仪分析了杂化结构的成分及其相对含量,结果显示体系中的Fe主要以α-Fe、γ-Fe和Fe3C的形式存在,并且Fe的含量随噻吩含量的增加不断增加。通过研究纳米铁颗粒的形成及其在碳纳米管表面的沉积,揭示了CNTs/FeNP杂化结构的形成机理。     

碳纳米杂化材料/环氧树脂复合材料界面性能的探讨

通过将不同比例的石墨烯/碳纳米管杂化材料(石墨烯与碳纳米管质量比为1∶1、1∶2和2∶1)添加到环氧树脂体系中制备碳纳米杂化材料/环氧树脂复合材料体系。通过研究复合体系的流变行为和差示扫描量热法(DSC)行为来分析碳纳米材料和环氧树脂之间的界面性质,得出结论:碳纳米杂化材料的加入虽会在一定程度上限制固化反应的进行,但会增大树脂和填料之间的自由体积,这样就可以提供给大分子链段更多移动空间,由流变行为知1∶1的杂化材料与树脂之间的界面亲和性是最好的。     

碳纳米管的表面修饰及其对碳纳米管/氟橡胶复合材料导电性能的影响

分别采用混酸和四氟化碳(CF4 ) 等离子体处理技术对碳纳米管(MWCNTs) 进行了表面修饰, 将处理前后的碳纳米管进行了XPS 和SEM 测试, 获得了处理后前的表面形貌和结构, 并采用溶液浇注的方式制备了MWCNTs/氟橡胶(FE) 复合材料, 探讨了不同碳纳米管状态(未处理、混酸处理、CF4等离子体处理) 的导电性能, 结果表明两种表面处理方式可以使MWCNTs 表面接上极性官能团。而且在相同的碳纳米管添加量下(质量分数分别为0. 1 %、0. 5 %、1. 0 %、2. 0 %) , 酸处理MWCNTs/ FE 的渗流阈值最小, 达0. 5 %。      

碳纳米管表面改性对碳纳米管/尼龙66复合材料机械性能影响的研究

采用熔融共混法,在尼龙66基体中分别加入不同改性的多壁碳纳米管(MWCNTs)制备MWCNTs/尼龙66复合材料。考察MWCNTs改性方法对MWCNTs结构,以及不同改性MWCNTs对复合材料形貌和机械性能的影响。研究发现:通过酸化-氨化过程,在MWCNTs表面引入了酰胺基团;FESEM显示,胺化碳纳米管(D-MWCNTs)分散均匀于尼龙66基体中;随着D-MWCNTs的引入,与纯尼龙66相比,D-MWCNTs/尼龙66复合材料的拉伸强度和拉伸模量分别增加了12.7%和24.3%;储能模量,在玻璃化区域(-40℃)和橡胶区域(120℃),分别较纯尼龙66提高了133.1%和73.3%。这些研究结果证明,MWCNTs的均匀分散,有利于提高聚合物复合材料的机械性能。     

碳纳米管/环氧树脂复合材料的静电自组装制备及性能

采用静电自组装法制备了均匀分散的碳纳米管环氧树脂复合材料,并对比分析了普通碳纳米管和功能化碳纳米管对环氧树脂热学和电学性能的影响。采用透射电镜(TEM)观察到碳管和树脂乳液自组装形成"葡萄藤"状结构,扫描电镜(SEM)观察发现,碳管可在环氧树脂中均匀分散并形成网络。电、热性能研究发现,添加3%普通碳纳米管可降低环氧树脂表面电阻率7个数量级,导热系数较纯树脂提高112%,而羧基化碳纳米管表面电阻率仅降低4个数量级,导热系数仅提高86%。     

碳纳米管表面处理对碳纳米管/氟橡胶复合材料形貌及界面作用的影响

采用溶液浇注法制备了碳蚋米管(CNTs)/氟橡胶纳米复合材料,并对不同表面状态的碳纳米管(原始碳纳米管,酸处理碳蚋米管、CF<,4>等离子体处理碳纳米管)在复合材料中的分散以及碳蚋米管与氟橡胶的界面作用进行了研究.研究结果表明,经CF<,4>等离子体处理后的碳纳米管在氟橡胶中的分散性明显优于混酸处理碳纳米管,激光显微拉...     

碳纳米管/聚乙烯醇复合材料的制备及其导电性的研究

在碳纳米管的羧基化改性过程中采用不同的处理条件对羧基化程度进行对比分析,在碳纳米管/PVA复合材料的制备中采用不同的配比进行混合制备,再对此复合材料进行一系列测定以表征其电导性质.通过红外光谱及激光粒径分析仪对产品形态和结构进行了分析和表征,结果表明,所制备的碳纳米管,羧基已经成功接上碳管、表面形态较规整、纯度较高,具有较好的羧基化碳纳米管结构;热性能测试结果显示,复合材料膜的结晶温度有所提高;导电性能测试结果显示,复合材料呈现出典型的金属性导电性能.     

碳纳米管/氧化锌复合结构的可控合成

详细介绍了在碳纳米管基底上制备氧化锌纳米结构的多种方法,如蒸汽反应法、碳热还原法、原子层沉积法以及水热沉积法,探讨了不同方法和不同参数对氧化锌纳米结构及其性能的影响,结合目前实验分析了制备碳纳米管/氧化锌复合结构存在的问题及解决方案,展望了碳纳米管/氧化锌复合材料的发展方向和应用前景。     

TiO2-MWCNTs的制备及TiO2-MWCNTs/epoxy复合涂层性能

用混酸对多壁碳纳米管（MWCNTs）进行了酸化处理,然后通过溶胶-凝胶法制备了TiO₂包覆MWCNTs（TiO₂-MWCNTs）核壳材料,并通过X射线衍射（XRD）、热重分析（TGA）等手段对其包覆结果进行了验证。用硅烷偶联剂KH560对TiO₂-MWCNTs及MWCNTs进行了改性,分别制备了TiO₂-MWCNTs/epoxy、MWCNTs/epoxy复合环氧涂层以及纯环氧涂层,利用EIS测试了涂层的电学性能,通过材料试验机（MTS）测定了涂层的柔韧性,用扫描电镜（SEM）观察了涂层表面形貌。结果表明：TiO₂-MWCNTs在环氧树脂中具有良好的分散性,TiO₂-MWCNTs/epoxy复合涂层对腐蚀介质具有较好的抗渗透性能;TiO₂包覆后大大增加了涂层的柔韧性。     

DOPOMPC-APP-MWCNTs协同阻燃环氧树脂的制备

将无卤膨胀阻燃剂六(4-DOPO羟甲基苯氧基)环三磷腈(DOPOMPC)、聚磷酸铵(APP)及多壁碳纳米管(MWCNTs)复配后加入环氧树脂(EP)中,制备出新型阻燃复合材料DOPOMPC-APP-MWCNTs/EP。通过极限氧指数(LOI)、水平垂直燃烧和锥形量热法研究其阻燃性能。研究结果表明:MWCNTs的加入增强了膨胀阻燃体系的阻燃性能和力学性能,并在一定程度上改善了体系燃烧时的浓烟现象。当阻燃体系总质量分数为20%,MWCNTs质量分数为2%时,材料性能最优,其LOI达到36.8%,热释放速率峰值、有效燃烧热平均值、比消光面积平均值和CO释放率平均值与未阻燃EP相比分别下降了83.5%、31.5%、47.6%、50.0%,与DOPOMPCAPP/EP相比下降了83.5%、77.7%、83.7%、68.9%。SEM分析表明:添加MWCNTs后,燃烧炭层呈现出大面积交联网络状结构。     

MgO-微胶囊红磷/高抗冲聚苯乙烯复合材料的阻燃性能

通过熔融混合方法把MgO和（或）微胶囊红磷（MRP）加入高抗冲聚苯乙烯（HIPS）基体中制备了一系列不同组成的MgO-MRP/HIPS复合材料。采用极限氧指数（LOI）、垂直燃烧（UL-94）、锥形量热分析、TGA、SEM、XRD、FTIR等方法研究了复合材料的阻燃性能。结果表明,MgO和MRP单独使用时对HIPS的阻燃作用较小,但是当二者以适当比例共同使用时对HIPS有明显的协同阻燃作用。当MgO∶MRP∶HIPS的质量比为35∶15∶100时,复合材料的LOI为24.7%,UL-94级别达到V-0级,热释放速率和总热释放量显著降低,表现出良好的阻燃性能。MgO-MRP/HIPS复合材料在无氧条件下热分解时,MgO、MRP与HIPS之间无相互作用。但是,在空气中热分解或燃烧时,MgO和MRP均能够促进HIPS成炭。MgO-MRP/HIPS复合材料燃烧时能够在材料表面生成连续致密的炭层,起到防火屏障作用,提高材料的阻燃性能,燃烧残余物主要由结晶性MgO和含磷的无定形碳组成。此外,MgO-MRP/HIPS复合材料燃烧时MRP在气相也起到了一定的阻燃作用。     

Effect of imidazolium phosphate and multiwalled carbon nanotubes on thermal stability and flame retardancy of polylactide

A series of composites based on polylactide (PLA), have been prepared by melt-blending with multiwalled carbon nanotubes (MWNT) and Tri(1-hydroxyethyl-3-methylimidazolium chloride) phosphate (IP) functionalized MWNT (MIP). The morphology, thermal stability and burning behavior of the composites were investigated by Field Emission Scanning Electron Microscopy (FESEM), Thermogravimetric Analysis (TGA) and Cone Calorimeter Test (CCT), respectively. Significant improvement in fire retardant performance was observed for the PLA/MIP composite from CCT (reducing both the heat release rate and the total heat release) and TGA (increasing the char residue) compared to PLA/MWNT. SEM and Raman spectroscopy were utilized to explore the surface morphology and chemical structure of the char residues. It revealed that the catalytic charring effect of IP, the physical crosslinking effect of MWNT, and the combined effect of both IP and MWNT (forming continuous and compact char layers) were very efficient in improving the flame retarding properties of PLA/MIP composite.     

多壁巴基纸/环氧复合材料拉伸性能的影响因素

采用抽滤法制备了多壁碳纳米管(MWCNTs)纸(又称巴基纸), 研究了巴基纸增强不同环氧基体复合材料(巴基纸复合材料)的拉伸性能及其断口形貌, 分析了MWCNT含量、 树脂基体拉伸性能以及巴基纸与树脂的界面黏附作用对复合材料拉伸性能的影响。结果表明: 在MWCNT质量分数小于39.1%范围内, 增加碳纳米管含量, 可显著提高巴基纸/环氧复合材料的拉伸性能; 巴基纸/环氧复合材料的拉伸强度和模量与树脂基体的性能密切相关, 其拉伸破坏形式受基体的脆韧性影响显著; 相比较而言, 巴基纸与树脂间的黏附功对巴基纸/环氧复合材料拉伸性能的影响不明显。     

Polyamide 6 composites reinforced with glass fibers modified with electrostatically assembled multiwall carbon nanotubes

Glass fiber-multiwall carbon nanotubes (GF-MWCNTs) hybrid preforms were prepared by electrostatic assembly method. Negatively charged MWCNTs by oxidization treatment were directly adsorbed onto the surfaces of positively charged GF to form tunable structure. The thickness and morphology of GF-MWCNTs preforms can be controlled by the assembly pH value and the concentration of oxidized-MWCNTs solution. We demonstrate that GF-MWCNTs preforms have uniform and porous interconnected network structure of MWCNTs on the surfaces of GF using FESEM. The multi-scale composites with the hybrid preforms were prepared by melt compounding. The presence of MWCNTs with porous nanostructure helps in the formation of interpenetrating network with polyamide 6 (PA 6) at the interface layer. As a result, the tensile tests of these multi-scale composites exhibit higher tensile properties in comparison with composites with GF, showing a promising structural composite to replace the traditional GF-reinforced composites with limited improvement of the performance.     

Experimental and computational investigations on fire resistance of GFRP composite for building façade

Composite materials such as glass fibre reinforced polymers (GFRPs) possess the advantages of high strength and stiffness, as well as low density and highly flexible tailoring; therefore, their potential in replacing conventional materials (such as concrete, aluminium and steel) in building façade has become attractive. This paper addresses one of the major issues that hinder the extensive use of composite structures in the high-rise building industry, which is the fire resistance. In this study, a fire performance enhancement strategy for multilayer composite sandwich panels, which are comprised of GFRP composite facets and polyethylene foam core, is proposed with the addition of environmentally friendly, fire retardant unsaturated polyester resins and gel-coats. A series of burning experimental studies including thermo-gravimetric analysis (TGA) and single burning item (SBI) are carried out on the full scale composite sandwich as well as on single constituents, providing information regarding heat release rate, total heat release, fire growth rate, and smoke production. Experimental results are compared with fire safety codes for building materials to identify the key areas for improvements. A fire dynamic numerical model has been developed in this work using the Fire Dynamics Simulator (FDS) to simulate the burning process of composite structures in the SBI test. Numerical results of heat production and growth rate are presented in comparison with experimental observations validating the computational model and provide further insights into the fire resisting process. Parametric studies are conducted to investigate the effect of fire retardant additives on the fire performance of the composite sandwich panel leading to optimum designs for the sandwich panel.     

Novel approach for the selective dispersion of MWCNTs in the Nylon/SAN blend system

Multiwalled carbon nanotubes (MWCNTs) were coated with TiO₂ by sol gel process. The coating was confirmed by TEM, XPS and XRD. TEM analysis showed that rough coating was formed on the MWCNTs. These modified MWCNTs and pristine MWCNTs were dispersed in the blend of nylon 66 and SAN by melt blending. FESEM images showed that pristine MWCNTs were preferably dispersed in the nylon phase whereas TiO₂ modified MWCNTs confined to the SAN phase. The selective dispersion was explained on the basis of migration and stabilization of these high aspect ratio nanotubes in the Nylon/SAN blend system. The hydrogen bonding interaction between the CN group of SAN and surface hydroxyl group of TiO₂ coated MWCNTs has restricted the migration of modified MWCNTs from SAN to nylon phase.     

Effect of modified MWCNT on the properties of PPO/LCP blend

In this work we have coated multiwalled carbon nanotubes (MWCNTs) with SiC by solgel process and these modified MWCNTs are dispersed in PPO/LCP blend. The dispersion of these modified MWCNTs are analyzed by FESEM and found to be improved compared to pure MWCNTs. Thermal and mechanical properties of the modified MWCNTs added nanocomposites are higher than that of the pure MWCNTs added nanocomposites. PPO/LCP forms an incompatible blend while addition of unmodified and modified MWCNTs improves the compatibility between the blend partners.