Styrene, Polystyrene, and CA glue

You're correct - styrene is a shortened name for polystyrene. Some current kits are also molded from ABS. That's yet another version of styrene.

But I also noticed that some manufacturers use different types of styrene. They have different properties like hardness and resistance to certain solvents and paints. I suspect that none of the kits are made from pure polystyrene. I suspect that different manufacturers use different styrene additives.

And I saw the ads for the new CA glue in Micro-Mark and I took a double-take when they mentioned that it isn't for styrene.

Peteski

ABS is not really the same as styrene- the name stands for Acrylonitrile Butadiene Styrene (I hope spelling doesn't count). It's a related polymer, but is very different in properties. Smells a lot different when you heat it, too. My first job was working in an injection molding shop- we made dental spatulas out of brown ABS. Cleaning the plastic out of the machines at the end of the shift made really excellent fake dog crap (geez, I hope Dennis doesn't get all hot and bothered).

I'm no chemist but since polystyrene and ABS have "styrene" in common, aren't they both in a styrene family? I seem to recall a fairly recent magazine article (not sure if it was Model Railroader or Finescale Modeler) where they covered properties of both Polystyrene and ABS.

ABS seems to be stronger and bit more flexible than Polystyrene.

Many manufacturers of model trains use ABS for molding their model bodies. Kato is one of them. I have worked with ABS and polystyrene and their gluing properties are very similar. The liquid cements I use worked equally well on both. And CA adhesive of course does too.

Peteski

Well, I *am* a chemist and can tell you this:

Styrene is a substituted benzene and is a liquid at room temperature. Polystyrene is a bunch of styrene molecules linked together in a regular pattern. ABS uses a substituted styrene subunit, but the polymer properties are very different. Just like polystyrene has different properties than polyvinyl chloride, and those two have different properties than high-density polyethylene. The starting material, even if similar, is very, very important to the final functionality of the finished polymer. As a simpler example, I'll refer you to the very simple cholesterol molecule. It is the starting material for two molecules that look very much alike, but have vastly different functions: estrogen and testosterone.

The future is plastics, Benjamin. :)

E.P.

just one quicky, mrs robinson?

Thanks for the chemistry lesson Ed.

While it was enlightening I still look at Polystyrene and ABS from a modeler's perspective. Both materials have similar gluing properties (using the brands of glues/solvents which I have at my disposal). Next are the machining properties which while a bit different for each material still are well within acceptable range to me.

But plastic such a PVC and (especailly) HDPE aren't quite as useful to me as Polystyrene and ABS (and Acrylic).

I suppose that if we break things further down enough, everything is made from atoms of various basic elements like carbon and hydrogen and others. :-)

Peteski

That would be the point of discussing it in this particular newsgroup. ;)

The application of particular polymers to scale modelling wasn't the point of my post. I was merely clearing up some apparent misunderstandings/misinformation on the nature of the stuff hidden away in our stashes.

E.P.