Chemistry Forums for Students > Inorganic Chemistry Forum

Bathyscaphe Float

<< < (2/2)

Enthalpy:
Floats down to 2000-3000m sometimes use a "syntactic foam" made of microballoons in a polymer matrix. Microballoons are small hollow glass spheres, the polymer is often epoxy. The density varies between 400 and 600kg/m3 depending on the maximum depth.

I propose to mix microballoons of very different sizes to reduce the density. Usual slurries must contain 40-50%vol liquid to flow and prevent voids, but concrete mixes particles of very different sizes to use less water+cement. Similarly here, smaller microballoons would fill much of the volume between the bigger ones so the polymer matrix fills less volume and weighs less.

Microballoons for model hobbyists exist in varied sizes. A ratio of 10 is good, so the usual grain sizes 100-300µm and 2-4mm could serve. If available, a third size would save more mass. And as is known, a runny resin simplifies the use of microballoons.

The few oil industry papers I read don't mention this combination, but model hobbyists are inventive.

==========

Whether the syntactic foam operates deeper? If the spheres have much thicker walls, the composite doesn't float any more. Alternately, the epoxy can be removed, and the bigger spheres be of alumina, then you have Nereus' design, but it was lost at depth. I feel my proposal with lithium intrinsically safer against pressure.

Mixing different sizes of microballoons can serve beyond floats.

Marc Schaefer, aka Enthalpy

Enthalpy:
A varnish is simplest to apply on lithium. PE, PP, EPDM... are water-tight and unreactive to lithium. Toluene, xylene, short straight alkanes... dissolve them, some are compatible with lithium, and they evaporate. Dipping the lithium parts in a thick solution seem easiest.

Marc Schaefer, aka Enthalpy

Navigation

[0] Message Index

[*] Previous page