Polymers composites, with nanotubes

Grunlan JC, Mehrabi AR, Bannon MV, Bahr JL (2004). Water-based single-walled-nanotube-filled polymer composite with an exceptionally low percolation threshold. Adv. Mater. 16 150-154. 

Composites with Other Polymers Besides the composite materials presented so far, a multitude of further polymer composites with carbon nanotubes has been prepared and studied regarding their properties. After all, any given polymer is suitable to some extent to interact with different carbon nanotubes (pristine or functionalized). The number and range of possible combinations surpass the scope of this text, so the examples mentioned below inevitably have to remain incomplete. 

Particulate polymer composites with fibers are a very active area of development, particularly carbon nanotubes and nanofiber composites, and the new graphite and polymer composites [35]. This fact, combined with the continued interest in nancomoposites based in nanometric clays [36], suggests that improvements in mechanical properties of particulate and short-fiber polymer composite materials will continue to be reported. 

Thus several researchers have produced nanotube-polymer composites with mechanical increases close to the theoretical maximum using a variety of preparation and functional procedures. However, it could be argued that in some cases where nucleation of crystallinity occurs, nanotubes should only be considered as a pseudo-reinforcement agent in polymer composites. 

D. Kim, Y. Kim, K. Choi, J. C. Grunlan, C. Yu, Improved Thermoelectric Behavior of Nanotube-Filled Polymer Composites with Poly(3,4-Ethylenedioxythiophene) Poly(Styrenesulfonate). ACS Nano 2010,4,513-523. 

They further prepared PEDOT PSS/CNT composites with higher CNTs content (higher than 35 wt.%) by direct solution mixing [26], whose microstructures are different from those of segregated-network polymer composites. The nanotubes were pulled out from the composite rather than being fractured or embedded in the matrix, due to the high CNTs content, as shown in Figure 6.16. 

It is well known that the percolation threshold is strongly dependent on the aspect ratio. One-dimensional (ID) nanostructures, such as nanowires, nanotubes, and nanoribbons, have geometries that are favorable for the maintenance of connectivity at low content of active materials. Carbon nanotubes (CNTs) are a good representative example. Electrical percolation can be achieved in polymer composites with well-dispersed single-walled carbon nanotubes (SWCNTs) at levels as low as 0.03 wt% [69]. Recently, it has been reported that the formation of semiconducting nanofibers facilitates percolation in semiconducting/insulating polymer blends. 

Polymer composites with carbon compounds as fillers such as carbon black (CB), carbon fibers, carbon nanotubes, or graphite were highly conductive materials. The carbon compounds significantly reduced the electric resistance and resulted in conductive SMPC, which could be triggered by means of Joule heat as an indirect actuation method. The just mentioned carbon compounds could conduct electricity in the plane of each covalently bonded sheet due to the delocalization of outer... 

Later in 2008, Sitharaman et al. evaluated CNT composites in vivo for use as a synthetic bone substrate [42]. This involved the preparation of a porous biodegradable polymer composite with the inclusion of short (20—80 nm) single-walled carbon nanotubes (SWNTs). When the in vivo response of CNTs containing substrates was compared to a control without CNTs, the CNT composite showed 300% increase in bone area as observed in micro-CT analysis and bone area under histological analysis. 

Kim D, Kim Y, Choi K, Grunlan J C and Yu C H (2010) Improved thermoelectric behavior of nanotube-filled polymer composites with poly(3,4-ethylenediox5rthiophene) poly(styrenesulfonate), ACS Nano 4 513-523. 

Cebeci H, de Villoria R G, Hart A J and Wardle B L (2009) Multifunctional properties of high volume fraction aligned carbon nanotube polymer composites with controlled morphology, Compos Sci Techno 69 2649-2656. 

Peng H and Sun X (2009) Highly aligned carbon nanotube/polymer composites with much improved electrical conductivities, Chem Phys Lett 47 103-105. 

In this book, an internationally known team of researchers publish state-of-the-art results that detail the application of synthetic, petroleum-based polymers in the form of carbon fibers, carbon nanotubes and fibers, and micro- and nanofibrils as reinforcements for polymer composites. These organic materials are distinct from polymer composites with mineral reinforcement due to specific mechanical properties that allow the manufacture of lightweight products, of particular importance in aircrafts and transportation vehicles. 

Infusing the porous buckypaper with polymer is a facile way of improving the buckypaper mechanical properties and create polymer composites with high loadings of nanotubes (>60%). To increase the mechanical properties, sheets of buckypaper can also be inserted between laminates. Polymers or epoxies have been layered on top of buckypaper to develop a ply material that has electrochemical actuation properties [110-112]. 

K.J.D. MacKenzie and M.J. Bolton, Electrical and Mechanical Properties of Aluminosilicate Inorganic Polymer Composites with Carbon Nanotubes. J. Mat. Sci., (Submitted). 

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