Filler platelike

The type of filler plays an important role. Fillers which have a platelike structure are more efficient than fibers, and fibers are more efficient then particulates. 

One of the most comprehensive comparisons of data for many filled polymer systems is given in the review by Holliday and Robinson (1973), which also provides additional expressions not discussed here. Several points are of special interest. First, equations such as Kerner s (1956a,h) and Wang and Kwei s (1969) agree reasonably well for spherical particles, while Turner s (1946) equation is better for systems in which fillers are fibrous or platelike. Second, fibers and fabrics induce the greatest deviation from additivity (see Figure 12.36). Finally, the behavior of polytetrafluoro-ethylene is strikingly anomalous. 

The morphology of two kinds of dimensional different nanofillers, i.e., a platelike nanoclay and a globelike Si02 can be controlled by utilizing their filler-to-filler interaction in PPS [48]. 

Nanoscale fillers such as clays are used to improve the barrier properties of plastic films. The platelike fillers, in particular, with the relatively higher tortuosity deliver lower gas permeabilities (Alperstein, 2005). At a volume fraction d> of the nanofiller, the permeability P of a gas through the polymer (Picard et al., 2007), depends on the value of tortuosity t of the nanoscale filler ... 

Commercial grades of talc used for plastics applications are line-ground products consisting of thin platelets, preferably white in color. Because of their platelike structure, these grades are considered reinforcing fillers, as distinguished from particulate mineral extender fillers. 

Osman and Atallah have reported a comparative study on the effect of filler particle shape, size and surface treatment on polymer crystallinity and gas permeability using spherical and plate-like inclusion in HDPE. Platelike inclusions strongly reduce the polymer permeability coefficient while the spherical particles do not have any effect on it. The reduction in gas permeability depends on the average aspect ratio of the fillers, which in turn... 

Kaolin (clay) is a widely used filler for thermoplastic polymers because of its reinforcing effects on mechanical properties, such as stiffness and strength, with however certain negative effects on impact resistance. Clays are typically used at 20-50% wt in polymer composites, and commercially available grades have aspect ratio between 4 and 12, and average particles in the 0.5-2.3 pm range. Because kaolin has a platelike structure with a high... 

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