[Enthalpy]

Hello nice people!

As a teenager I once obtained a polymer... But which one?

I had dry NaOH in a test tube as d=1mm balls, plus some Aluminium balls, both coming directly from a household product sold to clean toilet flows.
I poured Cl₃C-CH₃ (1,1,1-trichloroethane sold as thinner for tipp-ex) on them. All at room pressure and temperature, and under the best teenager practices of unknown purity, uncontrolled proportions and approximate cleanliness.

An emulsion formed and buoyed to the surface where it formed a solid stopper, about 1/3 the volume of trichloroethane (maybe limited by the available NaOH). I had to break the test tube to get the stopper.

The polymer (I suppose it was) looked compact, it was white, softer than polypropylene but much harder than wax, EPDM or glue for hot glue gun - about as soft as polymethylpentene. Its density could match a polyolefine, but I had no means to measure it.

It burned like a polyolefin, with the faint smoke and typical flame and odour. An odour very different from to polymers containing oxygen like POM or chlorine like PVC. A quiet flame and faint smoke very different from multiple-bonds polymer like unloaded latex or polybutadiene.

A tridimensional network of C-CH₃ would have an amount of hydrogen compatible with the reactants, but I'd expect it (wrongly?) to be a soft elastomer.

Can you suggest what it was? Thank you!
Marc Schaefer, aka Enthalpy

[Enthalpy]

Many tridimensional networks are hard, so after all maybe my polymer was 3D.

Could it have any use? Polymer designers are happy when they obtain a strong and stiff fibre that resists heat, but when I'm a mechanical designer I need more varied properties depending on the use: very low density, high or low gas permeance, high volume compressibility, big or small rebound, big deformation and shock absorption... I'm sure many lab creations were abandoned that would have met specific uses.

Ideas about the composition? Have you met an oxygen-containing polymer that smells paraffinic when burning? Thanks!

[Arkcon]

Where did you get the aluminum?  If this was wadded up commercial aluminum foil, then the problem becomes too complex -- commercial aluminum foil contains many impurities. 

[vex]

Have you considered repeating it? I don't know enough about polymer chemistry to help you identify it, but I'm sure you know a lot more now than your teenage self did. Maybe a repeat will re-reveal some more important details to you and at least give you a better chance of identification, if you don't have access to any analytical devices and can't figure it out with spectroscopy.

It sounds like it'd be easy enough to do, considering you did it in your garage as a teen. 

[Enthalpy]

Thank you!

Aluminium came as solid grains already mixed with the sodium hydroxide, supposedly to catalyse the reaction with peptides. Hence I have no slightest idea about its composition...

Repeating the experiment looks easy, yes. Whether I know more now? Maybe...
http://www.franquin.com/gaston/popup.php?img=/images/gaston/inventions/popup/03.jpg
I haven't studied chemistry meanwhile, because an other passion took over.

Was the polymer oxygen-free? I doubt now. Hot glue guns melt a copolymer with PVA and it smells paraffinic, so maybe there were oxygen atoms in the links.

[Arkcon]

I'm wondering how clean your trichloroethane was, as well.  Maybe it was pure, but then again, if it was art student paint thinner, it may have had additives, that simply dropped out of solution once the solvent was lost.  Again, like vex: said, maybe you'd care to repeat the procedure, with reagents of chemical purity, to see if you get the observed polymer again..

[zoork34]

I suspect the hydroxide acted as a base and did an elimination reaction on your trichloroethane, giving you vinyl dichloride, a very unstable compound which could easily polymerize into poly(vinyldichloride) with some light or heat.  Just like PVC, but with an extra chloride.  I doubt the aluminum played a role. 

[Enthalpy]

What surprises me is that, when burning it, I didn't notice the pungent odour of chlorine-containing polymers, especially PVC. Nor did it produce the smoke of PVC. It burned easily and gently like a paraffin does - or maybe an oxygen-containing polymer.

[Enthalpy]

Do you see any chance that I got a sort of polyketone, just one CH₂ shorter than the usual one obtained from CO and C₂H₄? At least the flame's smell was compatible with C, H, O but not with Cl.

Experiment again: easy, but I still have no analysis means.

[Enthalpy]

Resembling PVDF, maybe the short polyketone is ferroelectric too? It depends on how the chains arrange in the solid and on the temperature. The usual polyketone, with one -CH₂- more, is too symmetric to be ferroelectric.

A ferroelectric material keeps a permanent polarization after the application of a strong electric field. Then, it behaves similarly to a piezoelectric material, or even better in most applications. Uses as memory devices were investigated too.

The short polyketone would avoid fluorine in the production and destruction. And if my teenager tinkering really produced it, then it's facile.

Marc Schaefer, aka Enthalpy

[Enthalpy]

The usual polyketone, with one -CH₂- more, is too symmetric to be ferroelectric.

Failed! The usual polyketone is known to be ferroelectric, pyroelectric, optically nonlinear, etc. From:
Asymmetric Catalysis from a Chinese Perspective, edited by Shengming Ma

That's encouraging. The asymmetric one, with a C₂ chain per period instead of C₃, must be more strongly ferroelectric.

I ignore if producing a polyketone with C₂ chain per period is easy, nor if I did it, so may I suggest to try the polyketone with C₄ chain per period? Less polar but unsymmetrical.

The C₃ chain per period is obtained from carbon monoxide and ethylene or propylene over a catalyst
https://en.wikipedia.org/wiki/Polyketone
so maybe cyclopropane instead of ethylene makes the C₄ chain per period? One process sends the gases on warm solid catalyst, so more heat looks possible. Substituted cyclopropane can make a stiffer polymer chain.

As usual, lamination helps put the macromolecules straight and parallel, drawing or extrusion too.

Marc Schaefer, aka Enthalpy

[jerkycarcass]

I've seen CaOH be used to dehydrochlorinate (-HCl) trichloroethane to obtain vinylidene chloride. That has a great double bond there to polymerize into a chlorinated polyethylene. Im sure NaOH would have a similar effect as a catalyst as CaOH if not act as an even better catalyst.

[Borek]

I've seen CaOH

You have not.

[wildfyr]

I'm sure he means Ca(OH)₂

[Borek]

Thank you, capt. Obvious