Carbon nanotube-reinforced composites properties

Seidel, G. D. and Lagoudas, D. C. Micromechanical analysis of the effective elastic properties of carbon nanotube reinforced composites. Mech of Mater., 38, 884-907 (2006). 

For CNTs not well bonded to polymers, Jiang et al. [137] established a cohesive law for carbon nanotube/polymer interfaces. The cohesive law and its properties (e.g., cohesive strength, cohesive energy) are obtained directly from the Lennard-Jones potential from the van der Waals interactions. Such a cohesive law is incorporated in the micromechanics model to study the mechanical behavior of carbon nanotube-reinforced composite materials. CNTs indeed improve the mechanical behavior of composite at the small strain. However, such improvement disappears at relatively large strain beeause the eompletely debonded nanotubes behave like voids in the matrix and may even weaken the composite. The increase of interface adhesion between CNTs and polymer matrix may significantly improve the composite behavior at the large strain [138]. 

Another method to improve the mechanical properties such as interfacial strength is to add nanosized carbon fiber-reinforced particles into the composite [18-20]. A strong influence of a uniform dispersion of the small-sized fibers or partides on the composite properties of advanced nanocomposites, such as carbon nanotube-reinforced composites was also reported [21-24]. However, few papers mention the enhancing method for improving the interfacial adhesion between fiber and matrix in a natural BF composite. 

Effective elastic properties for carbon nanotube reinforced composites are obtained through a variety of micromechanics techniques [76]. Using... 

CNTs can enhance the thermal properties of CNT-polymer nanocomposites. The reinforcing function is closely associated with the amount and alignment of CNTs in the composites. Well-dispersed and long-term stable carbon nanotubes/ polymer composites own higher modulus and better thermal property as well as better electronic conductivity (Valter et al., 2002 Biercuk et al., 2002). Both SWNT and MWNT can improve the thermal stability and thermal conductivity of polymer, the polymer-CNT composites can be used for fabricating resistant-heat materials. 

Biercuk MJ, Llaguno MC, Radosavljevic M, Hyun JK, Johnson AT (2002). Morphological and mechanical properties of carbon-nanotube-reinforced semicrystalline and amorphous polymer composites. Appl. Phys. Lett. 80 2767-2769. 

Z. Ounaies, C. Park, K.E. Wise, E.J. Siochi, and J.S. Harrison, Electrical properties of single wall carbon nanotube reinforced polyimide composites, Compos. Sci Technol., 63(11) 1637-1646, August 2003. 

Concerning carbon nanotube-reinforced silicon nitride matrices, only a few reports have so far been published [19]. In this case, hot isostatic pressing has been used for composite processing. The carbon nanotubes remained in the microstructure only under low pressures (2 MPa) they connect the silicon nitride grains and produce a 15-37% improvement of the mechanical properties as compared with other carbon-filled samples (Fig. 19.11). Increase of pressure... 

Carbon nanotubes can be used in reinforcing polymer matrix composites in two ways a) as the sole reinforcing phase (CNTRP), or b) as an additional reinforcing phase in conjunction with carbon fibers (CF+CNT) in a hybrid composite. Carbon nanotubes reinforced plastics (CNTRP) can be prepared by several methods, as described in section 15.1.3. Both CFRP and CNTRP composite structures can be joined using structural adhesives but machining and drilling are difficult as a result of the widely different properties of their constituents. 

F. Ye, L. Liu, Y. Wang, Y. Zhou, B. Peng, and Q. Meng, Preparation and mechanical properties of carbon nanotube reinforced barium aluminosilicate glass-ceramic composites. Script. Mater., 55, 91 M (2006). 

Tai, N.-H., Yeh, M.-K., and J.-H. Liu. 2004. Enhancement of the mechanical properties of carbon nanotube/ phenolic composites using a carbon nanotube network as the reinforcement. Carbon 42 2774-2777. 

Kostopoulos V, Baltopoulos A, Karapappas P, Vavouliotis A, Paipetis A. Impact and after-impact properties of carbon fibre reinforced composites enhanced with multi-wall carbon nanotubes. Compos Sci Technol 2010 70(4) 553—63. 

Tserpes, K. I. and Chanteli, A. Parametric numerical evaluation of the effective elastic properties of carbon nanotube-reinforced polymers. Composite Structures, 99, 366-374 (2013). 

Wemik, J. M., Comwell-Mott, B. J., and Meguid, S. A. Determination of the interfacial properties of carbon nanotube reinforced polymer composites using atomistic-based continuum model. Inte. Jour, of Sol. and Struct., 49, 1852-1863 (2012). 

AyatoUahi, M. R., Shadlou, S., and Shokrieh, M. M., Multiscale modeling for mechanical properties of carbon nanotube reinforced nanocomposites subjected to different types of loading. Composite Structures, 93, 2250-2259 (2011). 

The properties of carbon nanotubes are not only sensitive to their diameter and chirality but are also highly anisotropic. The stiffness, strength and electrical, magnetic and optical properties of the nanotube-reinforced composites strongly depend on the orientations of the nanotubes. Therefore, it is crucial to obtain the controllable alignment of the nanotubes in the nanocomposite. 

Mathur, R. B. Pande, S. Singh, B. P. Dhami, T. L. Electrical and mechanical properties of multi-walled carbon nanotubes reinforced pmma and ps composites. Polym. Comps. 2008, 29, 717-727. 

Xiao, K. Q. Zhang, L. C. Zarudi, I. Mechanical and rheological properties of carbon nanotube reinforced polyethylene composites. Comp. Sci. Technol. 2007, 67, 177-182. 

Manufacturing and Electrical Properties of Carbon Nanotube Reinforced Polymer Composites... 

To summarize, the mechanical properties of carbon nanotube reinforced polymer composites mainly depend on the following factors ... 

Liu T X, Phang I Y, Shen L, Chow S Y and Zhang W D (2004) Morphology and mechanical properties of multiwalled carbon nanotubes reinforced nylon-6 composites, Macromolecules 37 7214-7222. 

The recent work of Kim et al. [96] discloses the structure and the electrical properties of PPTA/multiwalled carbon nanotubes (MWCNT) composites obtained by in situ polymerization. These composites exhibited improved electrical conductivity. Ground PPTA/MWCN particles were shown to behave as electrorheological (ER) material. It seems that preparing of such less usual all-aramid composites or using PPTA as matrix to be reinforced by CNT may be an interesting pathway toward composite materials, requiring, however, improved manufacturing processes. 

Carbon nanotubes are long cylinders of covalently bonded carbon atoms and have a diameter from a few angstroms to several tens of nanometers. Carbon nanotubes have exceptional mechanical properties [47-50], and extensive research work has been carried out on carbon nanotube-reinforced polymer composites [46-52]. However, weak interfacial bonding between carbon nanotubes and polymers leads to poor stress transfer, and this has limited the full realization of carbon nanotubes as reinforcements for polymers. Therefore, chemical functionalization of carbon nanotubes has been conducted. 

Zeng, H.L. Gao, C. Wang, Y.P. Watts, P.C.P. Kong, H. Cui, X.W. Yan, D.Y. (2006a). In situ polymerization approach to multiwalled carbon nanotubes-reinforced nylon 1010 composites Mechanical properties and aystaUization behavior. Polymer, 47, 113-122. 

El Badawi N, Ramadan AR, Esawi AMK, El-Morsi M (2014) Novel carbon nanotube-cellulose acetate nanocomposite membranes for water filtration applications. Desalination 344 79-85 Esteban EU-B, Matthew JK, Virginia AD (2013) Dispersion and rheology of multiwalled carbon nanotubes in unsaturated polyester resin. Macromolecules 46(4) 1642-1650 Fang L, Xue Y, Lin H, Shuai C (2011) Friction properties of carbon nanotubes reinforced nitrile composites under water lubricated condition. Adv Mater Res 284—286 611-614 Fangming D, John EF, Karen IW (2003) Coagulation method for preparing single-walled carbon nanotube/poly(methyl methacrylate) composites and their modulus, electrical conductivity, and thermal stability. J Pol) Sci Part B Polym Phys 41(24) 3333-3338... 

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