Electronic polymers crystalline

Figure 2.12 Photographs of polymer crystalline structures a) optical photograph of PP resin using polarizing light and filters, and b) electron micrograph of sPS resin (courtesy of Robert C. Cieslinski of The Dow Chemical Company)...

The catalytic activity and selectivity of platinum, palladium, rhodium and ruthenium salts supported on various polyamides was studied, and the correlation between their reduction capability to the metallic state and the formation of coordination complexes with polyamide was established [115]. Concerning supported metals, the influence of the geometrical factor and the feasibility of electronic interaction of the supported metal with polyamide was discussed. It was found that the activity of Rh complexes decreases with an increase in the distance between amide groups of polyamide and correlates with the change in polymer crystallinity [107]. 

Morphology of the polymer at and away from the surface of the additive particles, is conveniently determined by polarised light microscopy and, where higher resolution is required, by electron microscopy. More detailed consideration of the effects of particulate additives on polymer crystallinity is presented elsewhere in this book. 

There are four basic methods in wide use for the study of polymer crystallinity X-ray diffraction, electron diffraction, infrared absorption, and Raman spectra. The first two methods constitute the fundamental basis for crystal cell size and form, and the latter two methods provide a wealth of supporting data such as bond distances and intermolecular attractive forces. These several methods are now briefly described. 

Compatibility of additives with polymer, and their effect on polymer crystallinity, were evaluated using differential scanning calorimetry. Scanning electron microscopy was used to follow additive dispersion. WAXS and optical microscopy were used to determine effect of additives on crystallization kinetics and spherulite formation. ... 

Generally, the structure of polymers can be considered to be made from domains which can be discriminated easily from each other by a sufficient difference of their electron densities (contrast). Examples are copolymers consisting of soft and hard domains, semi-crystalline polymers (crystalline phase is denser than the amorphous regions) and porosity(voids) within a material. In this case it is advantageous [46, 60] to perform an edge enhancement by applying the Laplacian operator... 

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