Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: Titanscape on 24/12/2004 15:49:10
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What do you get if you mix molten Gallium with molten plastic well, and let it cool?
Titanscape
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An amorphous heterogeneous blob of crap?
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Gallium melts at 30 C, most plastics melt at higher temps. I suppose a good plastic would be polystyrene, since it has a low melting temp. The Gallium has a density of 5.9 g/cc, the styrene has a density near 1 g/cc, so they would separate even after thorough mixing. Tumbling the mixture might help mitigate that problem. The gallium has an expansion rate of 18 ppm/degreeC, typical of a metal. The plastic is at least 50 ppm/dC, and could easily be much more. As the metal-plastic conglomorate cools, the plastic will shrink away from the gallium and cracks will form in the mixture. Since the gallium will still be molten after the plastic solidifies, it will squeeze through those cracks, and may be extruded from the sample.
The result would be amorphous, except for the gallium which would form a crystalline solid below 30 C. The sample would also be heterogeneous. Whether or not it is crap depends upon if that result is what you seek for your end use.
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Thanks, I imagined a lead crystal effect in a clear polycarbonate mix.
Titanscape
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Glass is a special kind of alloy of metallaic oxides. It is mostly silicon dioxide, but also contains oxides of potassium, sodium, boron, cadmium, and sometimes lead oxide. All these metallic oxides have an affinity for each other and form solutions. In their metallic states, we call them metallic alloys. In their oxide states we call them glasses and ceramics.
Plastic is a polymer of hydrocarbons. It will not participate in the glassy alloy. There are fiber-glass reinforced plastics, but these are composite materials.