碳纳米管在熔融共混过程中分散性的影响因素

综述了在熔融共混制备碳纳米管(CNTs)/聚合物复合材料过程中CNTs的分散机理和分散性的影响因素。重点探讨了聚合物基体相对分子质量、螺杆转速、料筒温度、螺杆结构以及添加剂等因素对CNTs在热塑性聚合物基体中分散性的影响,最后对熔融共混分散CNTs方法进行了展望。     

超支化聚合物共价修饰碳纳米管的制备及应用研究

碳纳米管(CNTs)具有很多优良性能,但由于在聚合物基体分散性差,限制了其广泛应用。超支化聚合物是高度支化的大分子,具有低黏度、高溶解性及含有大量末端基团等特点。利用超支化聚合物共价修饰CNTs,不仅可以提高CNTs在聚合物基体中的分散性,还能使CNTs拥有新的功能。介绍了超支化聚合物共价修饰CNTs的方法,探讨了其在生物医学、纳米材料等方面的应用前景,最后对超支化聚合物共价修饰CNTs的发展提出了建议。     

CNTs的表面修饰及其在EP纳米复合材料中应用的研究进展

介绍近年来碳纳米管(CNTs)的有机表面修饰研究进展。通过对CNTs的表面修饰可改善CNTs在有机溶剂中的溶解性及在聚合物基体中的分散性。综述了CNTs改性环氧树脂(EP)纳米复合材料的研究现状,并对今后CNTs改性纳米复合材料的发展方向进行了展望。     

碳纳米管/橡胶复合材料的制备方法及性能研究现状和进展

介绍近年来碳纳米管（CNTs>）改性的方法,包括共价键修饰和非共价键修饰。概述CNTs/橡胶复合材料的制备方法,包括机械共混法、熔融共混法、溶液共混法、喷雾干燥法、胶乳共混法、淤浆共混法,分别指出这些方法的优势及存在的问题。从CNTs/橡胶复合材料的力学性能、导热性能和导电性能着手,概述其研究进展,分析CNTs/橡胶复合材料领域存在的问题,展望CNTs/橡胶复合材料的制备及性能发展。     

碳纳米管/聚合物基导热复合材料研究进展

碳纳米管（CNTs）由于优异的轴向导热性能,是目前制备高热导率聚合物基复合材料的一类重要填料。本文综述了近年来CNTs增强聚合物复合材料的研究进展,探讨了CNTs/聚合物复合材料的导热机理以及CNTs用量、尺寸及结构、表面改性、混杂CNTs粒子和聚合物基体结构等因素对CNTs/聚合物复合材料热导率的影响。同CNTs/聚合物的电导率相比,热导率远低于预期值,归因于CNTs/树脂界面间的声子频率失配现象导致了声子在界面的散射及很高的界面接触热阻,从而降低了体系热导率。分析和总结了改善体系热导率的方法和措施,采用特殊工艺使CNTs在基体内形成特殊的隔离结构或者取向结构是CNTs/聚合物导热复合材料的未来研究及发展方向。     

碳纳米管的表面修饰及其在聚合物中的应用

介绍了碳纳米管的有机共价键化和有机非共价键化修饰,以及碳纳米管在聚合物中应用的情况。通过碳纳米管表面修饰技术制备可溶性碳纳米管,可以解决碳纳米管的纯化和分散问题：碳纳米管具有特殊的结构,独特的电学、力学性能和化学稳定性,在场发射器件、电子晶体管、储氢、太阳能利用、高效催化剂等方面具有诱人的应用前景。     

碳纳米管在PA 6/PP共混体系中的选择分散性

采用熔融共混法制备了聚酰胺（PA）6／聚丙烯（PP）／碳纳米管（CNTs）三元复合材料。研究了相容剂的结构、CNTs的表面性质对复合体系微观分散性的影响。结果表明,在相容剂增容条件下,PP可以在PA6基体中均匀分散,呈明显的“海-岛”结构;CNTs的表面有机基团决定了其在不同相中的分散,强酸处理的CNTs1^#表面氧化生成的羧基与PA6的胺基反应,在不同相容剂增容的PA6与PP共混体系中CNTs1^#均分散在PA6相中;而氧化后与己内酰胺原位聚合的CNTs2^#表面生成低聚合度的PA6,表面引入了一定的胺基,与双羧基相容剂（衣康酸与苯乙烯共聚接枝聚丙烯）反应,可使CNTs2^#进入PP相中。     

PVP表面修饰碳纳米管在环氧树脂中的应用

以环氧树脂(EP)为基体,聚乙烯吡咯烷酮(PVP)表面修饰的碳纳米管(CNTs)为增强剂,采用模具浇铸法,制备CNTs/EP纳米复合材料。使用红外光谱(FTIR)、扫描电镜(SEM)、差示扫描量热仪(DSC)、热失重分析仪(TG)、冲击试验机和电子万能试验机对材料的结构和性能进行测试和表征,并分析微观结构和性能之间的关系。结果表明:PVP修饰的CNTs管壁相比原始的CNTs粗糙,两亲性聚合物PVP已经接枝CNTs表面,并且提高CNTs和EP之间的界面结合作用。随着PVP用量的增加,复合材料的冲击强度和弯曲强度有一定程度的提高。含量为0.25%PVP修饰后的CNTs在保证弯曲模量、弯曲强度和热稳定性基本不变的情况下,较好的提高纳米复合材料的韧性和耐热性,其中冲击强度提高59%,Tg提高近20℃,所以其综合性能最优。     

表面活性剂应用于碳纳米管分散处理的研究现状

由于碳纳米管(CNTs)的强分子间作用力使得在水溶液和其他体系中确保其具有良好分散性一直是一个挑战,致使CNTs复合材料功能化和可靠性的进展要求探索出完善的处理工艺,以发挥其优异的机械、电学、磁学和光学性能。而表面活性剂对CNTs结构的非共价化学修饰能确保处理后的CNTs结构的完整性,从而成为广泛使用的分散剂。本文综述了各种表面活性剂处理CNTs的应用研究,并分析了其分散机理,同时也总结了近来利用表面功能化分散CNTs的一些双亲分散剂的应用研究。在此基础上给出表面活性剂应用于分散CNTs的研究方向,并为今后的研究提供一些建议。     

中国塑料专利

正聚合物/碳纤维中空复合材料及其制备方法所述中空复合材料中,碳纤维均匀地分散在聚合物中,聚合物分子在碳纤维表面附生结晶形成取向的串晶结构;其中,碳纤维占复合材料质量比例为1%～20%。本发明方法制备的中空复合材料最显著的优点是:(a)接枝到碳纤维表面的聚合物分子链与基体中的聚合物分子链相互穿插堆砌形成片晶,能够增强了碳纤维与聚合物基体之间的界面结合力;(b)聚合物分子在碳纤维表面附生结晶形成高取向的杂化结构使得中空复合材料可能表现出刚韧兼顾的力学性能。/四川大学,CN106279872B,2019-04-12     

Preparation,structure and properties of thermoplastic olefin nanocomposites containing functionalized carbon nanotubes

The morphology and properties of multiwalled carbon nanotube modified polypropylene (PP)/ethylene–octene copolymer blends were studied. Polypropylene chains are covalently grafted onto the surface of carbon nanotubes (CNTs) in order to improve their interaction with the polymer matrix. It is observed that functionalization of CNTs improves their dispersion and increases the interfacial bonding between CNTs and polymer matrix. The functionalized CNTs are selectively distributed in the continuous polypropylene phase. The size of the dispersed elastomer phase decreases after the addition of CNTs. Functionalized CNTs act as a nucleating agent and increase the crystallinity of the polypropylene. More importantly, an important increase in impact strength, stiffness and toughness can be achieved through introducing functionalized CNTs. Copyright © 2011 Society of Chemical Industry     

Functionalization of carbon nanomaterials for advanced polymer nanocomposites: A comparison study between CNT and graphene

The allotropes of carbon nanomaterials (carbon nanotubes, graphene) are the most unique and promising substances of the last decade. Due to their nanoscale diameter and high aspect ratio, a small amount of these nanomaterials can produce a dramatic improvement in the properties of their composite materials. Although carbon nanotubes (CNTs) and graphene exhibit numerous extraordinary properties, their reported commercialization is still limited due to their bundle and layer forming behavior. Functionalization of CNTs and graphene is essential for achieving their outstanding mechanical, electrical and biological functions and enhancing their dispersion in polymer matrices. A considerable portion of the recent publications on CNTs and graphene have focused on enhancing their dispersion and solubilization using covalent and non-covalent functionalization methods. This review article collectively introduces a variety of reactions (e.g. click chemistry, radical polymerization, electrochemical polymerization, dendritic polymers, block copolymers, etc.) for functionalization of CNTs and graphene and fabrication of their polymer nanocomposites. A critical comparison between CNTs and graphene has focused on the significance of different functionalization approaches on their composite properties. In particular, the mechanical, electrical, and thermal behaviors of functionalized nanomaterials as well as their importance in the preparation of advanced hybrid materials for structures, solar cells, fuel cells, supercapacitors, drug delivery, etc. have been discussed thoroughly.     

Dispersion, interfacial interaction and re-agglomeration of functionalized carbon nanotubes in epoxy composites

The surface, interfacial and dispersion properties of carbon nanotubes (CNTs), and the mechanical properties of the CNT/epoxy composites affected by CNT functionalization are investigated. It is demonstrated that there exists strong correlations between amino-functionalization, dispersion, wettability, interfacial interaction and re-agglomeration behaviour of CNTs and the corresponding mechanical and thermo-mechanical properties of CNT/epoxy composites. The amino-functionalized CNTs exhibit higher surface energy and much better wettability with epoxy resin than the pristine CNTs, and the attached amine molecules arising from the functionalization effectively inhibit the re-agglomeration of CNTs during the curing of resin. These ameliorating effects along with improved interfacial adhesion between the matrix and functionalized CNTs through covalent bonds result in improved flexural and thermo-mechanical properties compared with those without functionalization.     

Synthesis and processing of PMMA carbon nanotube nanocomposite foams

Poly(methyl methacrylate) (PMMA) multi-walled carbon nanotubes (MWCNTs) nanocomposites were synthesized by several methods using both pristine and surface functionalized carbon nanotubes (CNTs). Fourier transform infrared (FTIR) spectroscopy was used to characterize the presence and types of functional groups in functionalized MWCNTs, while the dispersion of MWCNTs in PMMA was characterized using scanning electron microscopy (SEM). The prepared nanocomposites were foamed using carbon dioxide (CO₂) as the foaming agent. The cell morphology was observed by SEM, and the cell size and cell density were calculated via image analysis. It was found that both the synthesis methods and CNTs surface functionalization affect the MWCNTs dispersion in the polymer matrix, which in turn profoundly influences the cell nucleation mechanism and cell morphology. The MWCNTs are efficient heterogeneous nucleation agents leading to increased cell density at low particle concentrations. A mixed mode of nucleation mechanism was observed in nanocomposite foams in which polymer rich and particle rich region co-exist due to insufficient particle dispersion. This leads to a bimodal cell size distribution. Uniform dispersion of MWCNTs can be achieved via synergistic combination of improving synthesis methodology and CNTs surface functionalization. Foams from these nanocomposites exhibit single modal cell size distribution and remarkably increased cell density and reduced cell size. An increase in cell density of ∼70 times and reduction of cell size of ∼80% was observed in nanocomposite foam with 1% MWCNTs.     

表面活性剂非共价功能化处理制备碳纳米管悬浊液

分别以十二烷基苯磺酸钠、十二烷基磺酸钠、十二烷基硫酸钠、十二烷基聚氧乙烯(23)醚、十六烷基三甲基溴化铵等表面活性剂为分散剂,水为溶剂,超声波作用下对硝酸纯化的碳纳米管进行非共价功能化处理,制备了初始浓度为2 g/L的碳纳米管悬浊液,并对处理后的碳纳米管进行定性分析. 结果表明,功能化处理后,表面活性剂吸附到碳纳米管表面,促进碳纳米管的分散. 定量分析了碳纳米管悬浊液的浓度,并根据碳管浓度随时间的变化研究悬浊液的稳定性. 结果表明,表面活性剂功能化处理所制碳纳米管悬浊液存放240 h后趋于稳定,碳纳米管浓度不再下降,最终碳纳米管悬浊液浓度因所用表面活性剂不同而在1.68~1.84 g/L范围内略有差异.     

Structure‐property relationship of substituted pyrrolidine functionalized CNT epoxy nanocomposite

Carbon nanotubes (CNTs) based polymer nanocomposites hold the promise of delivering exceptional mechanical properties and multifunctional characteristics. However, the realization of exceptional properties of CNT based nanocomposites is dependent on CNT dispersion and CNT‐matrix adhesion. To this end, we modified MWCNTs by Prato reaction to yield aromatic (phenyl and 2‐hydroxy‐4‐methoxyphenyl) substituted pyrrolidine functionalized CNTs (fCNT1 and fCNT2) and aliphatic (2‐ethylbutyl and n‐octyl) substituted pyrrolidine functionalized CNTs (fCNT3 and fCNT4). The functionalization of CNTs was established by Thermogravimetric analysis (TGA), Raman Spectroscopy, and XPS techniques. Optical micrographs of fCNT epoxy mixture showed smaller aggregates compared to pristine CNT epoxy mixture. A comparison of the tensile results and onset decomposition temperature of fCNT/epoxy nanocomposite showed that aliphatic substituted pyrrolidine fCNT epoxy nanocomposites have higher onset decomposition temperature and higher tensile toughness than aromatic substituted pyrrolidine fCNT epoxy nanocomposites, which is consistent with the dispersion results of fCNTs in the epoxy matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42284.     

高性能CNTs/EP纳米复合材料的制备及固化行为

从CNTs/环氧树脂纳米复合材料界面作用和CNTs在环氧树脂中的分散性、CNTs功能化和CNTs在环氧树脂中的定向排列等方面,详细介绍了高性能CNTs/环氧树脂纳米复合材料的制备方法.同时综述了CNTs/环氧树脂体系的固化反应机理和固化反应动力学等研究现状.不仅对现有研究结果进行了深入分析,还探讨了CNTs/环氧树脂纳米复合材料研究所面临的困难和挑战.     

Decoration of multi-walled carbon nanotubes by polymer wrapping and its application in MWCNT/polyethylene composites

ABSTRACT: We dispersed the non-covalent functionalization of multi-walled carbon nanotubes (CNTs) with a polymer dispersant and obtained a powder of polymer-wrapped CNTs. The UV-vis absorption spectrum was used to investigate the optimal weight ratio of the CNTs and polymer dispersant. The powder of polymer-wrapped CNTs had improved the drawbacks of CNTs of being lightweight and difficult to process, and it can re-disperse in a solvent. Then, we blended the polymer-wrapped CNTs and polyethylene (PE) by melt-mixing and produced a conductive masterbatch and CNT/PE composites. The polymer-wrapped CNTs showed lower surface resistivity in composites than the raw CNTs. The scanning electron microscopy images also showed that the polymer-wrapped CNTs can disperse well in composites than the raw CNTs.     

The effect of surface functionalization of carbon nanotubes on properties of natural rubber/carbon nanotube composites

The objective of this study was to prepare natural rubber composites filled with carbon nanotubes (CNTs) that show an electrical percolation threshold at very low CNT concentrations. Therefore, two methods of surface functionalization of CNTs were investigated to enable an improved dispersion of CNTs and chemical interaction between CNTs and rubber matrix. On one hand, the CNTs have been functionalized ex situ by acid treatment and silanization reaction with bis(triethoxysilylpropyl) tetrasulfide before mixing with the rubber and otherwise in situ functionalization was directly carried out during the processing of the composites in the internal mixer. The grafting of silane molecules onto CNT surface was established by Fourier transform infrared spectroscopy and scanning electron microscopy. Tensile tests revealed the outstanding properties of composites prepared by in situ silanization method. The in situ silanization led to a better dispersion of the CNTs and the formation of chemical linkages between CNT surface and rubber and this became manifest in higher reinforcement of the rubber, higher crosslink densities, and a lower electrical percolation threshold. It was also shown that the in situ silanization is retarding the vulcanization reaction. POLYM. COMPOS., 36:2113–2122, 2015. © 2014 Society of Plastics Engineer     

Thermal properties of hyperbranched polyborate functionalized multiwall carbon nanotube/polybenzoxazine composites

Using a noncovalent functionalization strategy, hyperbranched polyborate (HBb) acts as a solubilizer for carbon nanotubes (CNTs), and a stable HBb‐CNT dispersion in N‐methyl‐pyrrolidone was produced. The thermal properties of the resulting HBb‐CNT/polybenzoxazine (B‐BOZ) composites and their carbonized structures were investigated. Scanning electron microscopy demonstrated that the fracture surface of HBb‐CNT/B‐BOZ composites was rather rough and plenty of plastic deformation was exhibited. Thermogravimetric analysis indicates an improvement in the thermal stability of the composite with CNTs, especially that of 2.0 wt% CNT modified composite. The increase in the thermal stability is due to the good nanotube dispersion and the effective polymer‐CNT interaction. Graphite‐like boron carbonitride ceramic compounds were found after the composites were carbonized at 1,100°C for 2 h, and there was more B‐C, B‐N, and C‐N bonds in the carbonized HBb‐CNT/B‐BOZ composite than that of HBb/B‐BOZ composite. The result implied that CNTs can promote the ceramic process of HBb/B‐BOZ composite, and the strategy of introducing ceramic precursor into polymer composites may be useful to improve their ablation properties. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers