Inorganic nano fibers

POCs are composed of two or more phases. The matrix is the polyolefin with a continuous phase that surrounds the other phases. The filler could be a reinforcement material for the entire composite. The properties of the polyolefin composite are dependent upon the filler type (organic or inorganic), geometry (fiber, flake, particulate, or sphere), the type of matrix, and the size of filler (micro or nano). Figure 6.1 depicts a simple schematic classification of a polyolefin composite [28]. 

Nanoparticles used in PNCs are one-dimensional (e.g., fibers, tubes, whiskers), two-dimensional (platelets), or three-dimensional (spheres or nearly so, e.g., see Chapter 15). The latter ones are rather meso- than nano-sized and are used mainly in functionalized PNCs. Currently, structural PNCs of industrial interest contain platy inorganic substances that can be exfoliated into dispersions of individual platelets about r 1 nm (or less) thick examples are given in Table 16.1. 

The main drawback of epoxy thermosets is its brittleness. To solve this problem, they are commonly modified with reinforcements of different nature (elastomers, thermoplastics, inorganic p>articles), geometry (particles, fibers, platelets) and size (micro and nano) which provide additional mechanical energy absorption mechanisms. The dispersion of a second phase can be obtained using mainly two strategies (Pascault et al., 2002) ... 

The recorded history of short fiber technology starts over two thousand years ago with asbestos fibers and reaches into the future with silicon nano-whiskers and carbon nanotubes. Asbestos is derived from the solid phase, but today, the most important short inorganic fibers are derived from the vapor phase. 

A liquid phase, as opposed to a vapor or solid phase, includes dispersions, solutions and melts. Several processes, which yield continuous inorganic fibers directly from the melt, have been discussed in Chapter 4. Only one generic process, dry spinning, is known to yield one specific amorphous oxide fiber directly from a liquid phase other than that of a melt. All other processes which start with a liquid phase (see Chapters 8-12) yield first a solid, non-functional precursor or green fiber, and then a functional, nano- or polycrystailine ceramic fiber. Such refractory ceramic fibers are therefore directly derived from a solid phase, a precursor or a green fiber, and only indirectly from a liquid phase. 

The transcription of organogel superstructmes into semiconducting inorganics holds promise for the development of the next generation of nanos-tructured materials in electronics [103]. hi that connection, the organogel fibers of the A(LS)2 derivative 53 served as nucleation sites for the mineralization of CdS, which led to the formation of CdS nanofibers [77]. 

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