Carbon fiber aspect ratio

A carbon fiber—aspect ratio = 23 + carbon fibers—aspect ratio = 27. Data are from Ref. 67. 

Fig. 4.9 Effect of particle asperity on the relative viscosity of molten polymer suspensions. Particles studied were as follows , glass spheres , natural calcium carbonate A, precipitated calcium carbonate o, glass fibers—aspect ratio = 18 ...

There is little available data to analyze the predictive at ty of these modek to evaluate the through-the-plane conductivity of composites in which tte fibers are randomly oriented within a plane. In Delmonte s text there is limited data on the thermal conductivity of carbon fiber reinforced polyamide 66 composites, measured through the thickness of the plane of orientation of the fibers [26]. This data is summarized in Table 3. The fiber aspect ratios were taken from Fig. 8, based on the assumption that sufficient 3-D mixing occurred in the compounding and injection molding machines to reduce the fibers to an aspect ratio compatible with the maximum fraction associated with a random isotropic condition. The Hatta and Taya model does quite well in predicting the thermal conductivity across the plane of fiber orientation for these composites. 

As far as conducting fillers are concerned, we have rather a wide range of choice. In addition to the traditional and long used fillers, such as carbon black and metal powders [13] fiber and flaky fillers on organic or metal bases, conducting textures, etc recently appeared and came into use. The shape of the filler particles varies widely, but only the particle aspect ratio, the main parameter which determines the probability... 

The structural variety of the compounds that form fibers is as diverse as their chemistries. From glasses (fiberglass), and partially crystalline materials (carbon), to special three-dimensional arrays, including polymers, the small, elongate solids may have aspect ratios up to 5000. From our research and compilation (Appendices 1, 2) we noted many mineral and synthetic compounds that have structures characterized by basic linear units. Amphi-boles, the major mineral group mined as asbestos, are characterized as doublechain structures. Many of the minerals in Appendix 1 are polymorphic (di-or trimorphs), and where one member of a mineral series has been described as fibrous the others in the same series are likely to be able to grow as fibers as well. Probably all compounds with similar structures and compositions, mineral or synthetic, can form fibers, even though they are not presently listed. It is also clear that fibrous formation is not confined to compounds with linear structural units indeed the variety of crystalline structure patterns is remarkably diverse. 

While carbon fiber (thickness on the order of 1000 nm) composites offer very strong materials, carbon nanotubes make even stronger composites. These carbon nanotubes have aspect ratios of over 1000 (ratio of length to diameter). Further, because some carbon nanotubes are electrically conductive, composites containing them can be made to be conductive. A number of carbon nanotube matrixes have been made including using a number of engineering resins, such as polyesters, nylons, polycarbonates, and PPE. 

Carbon nanotubes (CNTs) are the strongest fibers that are currently known. They demonstrate amazing mechanical, thermal and electrical properties, while a low density and a very high aspect ratio (1-5). A lot... 

Kitano et al.61 also conducted a study on suspensions of elongated particles Fig. 4.9. Aspect ratios ranged from 1 (for spheres) to 27 (for carbon fibers). The results of this study are similar to those obtained for spherical particles. However, the larger the aspect ratio, the lower the volume fraction of solid at which the packing threshold is reached. The viscosity of the suspensions follow Eqn. (2), with a constant 0 that depends on the aspect ratio see Table 4.1. 

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