Conductive microfibril composite

The distance between conductive fillers is of great importance for electric conduction in the filled conductive polymer composite. It is widely accepted that the electrons can transmit or jump between the conductive fillers in the presence of an electric field, even if there is a gap between the fillers. However, this gap cannot be too large and is usually accepted to be lower than 10 nm. Thus, the distance between the outmost CB particles in one microfibril and those in another microfibril is a crucial factor for electric conduction between two microfibrils. Figure 13.5 shows the SEM micrographs of the cryofractured... 

Based on the discussion above, it is clear that the amount and distribution of the CB particles on the surface of microfibrils are very critical factors to determine the percolation threshold of i-CB/PET/PE composite. When the CB content in the PET phase is just beyond the percolation threshold of CB/PET compound, the continuous network of CB particles may be formed inside the microfibrils. However, there are hardly any CB particles on the surface of the CB/PET microfibrils and there exists a pure polymer layer below the surface of CB/PET microfibrils. This results in a high contact resistance among the microfibrils. The whole system exhibits an insulator state though the electrically conductive microfibrils may form a network. As the CB content in the CB/PET microfibrils reaches max> fhe number of CB paxticles on the surface evidently increases. Conduction pathways axe formed between some contact points in the microfibril network. With a further increase of CB content, the amount of CB particles on the microfibril surface increased significantly, and the electrically conductive contact points also increased. When the number of contact points is large enough to form a network to sustain the electron transmission in the whole... 

Zhang Y C, Dai K, Pang H, Luo Q J, Li Z M and Zhang W Q (2011) Temperature and time dependence of electrical resistivity in an anisotropicaUy conductive polymer composite with in situ conductive microfibrils, J Appl Polym Sci (in press). 

At the early stage of research on in situ composites, most work has been conducted on the LCP microfibril formation connected with the melt viscosity or viscosity ratio, composition, and flow mode, etc. These results have been summarized and reviewed by several researchers [11-17]. In the aspect of flb-rillation, the current work is only a supplement to those reviews, with additional new insights and results. We will summarize and review the recent work on the compatibility of LCP blends in this chapter. 

Microfibril Reinforced Polymer-Polymer Composite via Hot Stretching Electrically Conductive Functionalization... 

Usually, a composite filled with large specific ratio fibers or flakes has a lower percolation threshold than that filled with spherical conductive particles. The fillers with a high aspect ratio may also increase the tendency to form the co-continuous phases in polymer blend matrices [10]. These morphology-property relationships imply that if the conductive filler is preferential, or even totally localized in the minor phase or its surface (a-polymer) of a polymer blend, and the conductive filler/a-polymer blend is elongated or oriented to form conductive in situ microfibrils in the polymer matrix ([3-polymer), the composite obtained may have high conductivity (construction of 3D conductive in situ microfiber... 

From this view, the authors have used a new approach called melt extrusion-hot stretching-quenching to prepare two categories of CPC (isotropic and anisotropic CPC) based on in situ microfibril reinforced polymer-polymer composites. This chapter briefly describes our recent work on several conductive in situ microfibrillar reinforced composites via hot stretching. 

In this section, we attempt to suppress the influence of the to reduce the percolation threshold by localizing CB particles in the surfaces of in situ microfibrils [22]. When the conductive filler, a-polymer and /3-polymer are CB, PET and PE, we can obtain isotropic o-CB/PET/PE composites through preparation procedures in Figure 13.1. 

Xu X B, Li Z M, Yang M B, Jiang S and Huang R (2005) The role of the surface microstructure of the microfibrils in an electrically conductive microfibrillar carbon black/poly(ethylene terephthal-ate)/polyethylene composite, Carbon 43 1479-1487. 

Mallette J G, Quej L M, Marquez A and Manero O (2001) Carbon black-filled PET/HDPE blends Effect of the CB structure on rheological and electric properties, J Appl Polym Sci 81 562-569. Xu X B, Li Z M, Dai K and Yang M B (2006) Anomalous attenuation of the positive temperature coefficient of resistivity in a carbon-black-filled poljoner composite with electrically conductive in situ microfibrils, Appl Phys Lett 89 032105. 

Panamoottil SM, Potschke P, Lin RJT, Bhattacharyya D, Fakirov S (2013) Conductivity of microfibrillar polymer-polymer composites with CNT-loaded microfibrils or compatibilizer a comparative smdy. Express Polym Lett 7(7) 607-620 Pang J, Xu G, Bai Y, Yuan S, He F, Wang Y, Sun H, Hao A (2010) Molecular dynamics simulations of the interactions between p-cyclodextrin derivatives and single-walled carbon nanombes. Comput Mater Sci 50(2) 283-290... 

Fakirov S, Rahman Md Z, Poetschke P, Bhattacharyya D (2014) Single polymer composites of poly(butylene terephthalate) microfibrils loaded with carbon nanotubes exhibiting electrical conductivity and improved mechanical properties. Macromol Mater Eng 299(7) 799-806... 

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