Polystyrene -polyethylene topography

Figure 10.5 shows scanning electron micrographs of blend samples that were prepared as described in the Experimental Section . The etchant preferentially attacks polyethylene, producing a topography in which the polystyrene-rich domains are raised above the polyethylene domains. The interlamellar amorphous material provides a location for styrene to penetrate and polymerize. A considerable amount of polystyrene is present in the center of the spherulites. This is due either to amorphous polyethylene that is present in these locations or to voids that develop during crystallization... 

Abbreviations DMA, dynamic mechanical analysis DSC, differential scanning calorimetry He, helium PE, polyethylene PMMA, polymethylmethacrylate PP, polypropylene PS, polystyrene St-bend, steel disc with topography similar to that of pipe bend St-sb, steel disc with sandblasted surface... 

An alternative method is to use mixtures of concentrated sulfuric acid and potassium permanganate, giving contrast between crystals and amorphous domain that turns out to be applicable to many different polymers, e.g. polyethylene, polypropylene, poly(but-l-ene), polystyrene and poly(aryl ether ketone)s. The strong etchant degrades the amorphous phase more quickly than the crystals and the resulting topography is revealed by heavy metal shadowing. Replicates are prepared which are examined in the electron microscope. 

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