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Image: S2-P2-P6, by sculptor Roxy Paine.

About a year ago I was wandering around Maker Faire Bay Area thinking about polymerization. Collin had recently posted his now-world-famous cymatics video, and I was standing around talking to the TAP plastics folks about whether it might be possible to “freeze” cymatic forms by applying the sound waves to some kind of polymer resin that could then be solidifed, almost instantaneously, by adding a drop or two of catalyst. I had, you will not be surprised to learn, been drinking heroic amounts of coffee.

But in the subsequent process of researching fast polymerization reactions, I came across an intriguing term: Explosive polymerization. Visions of exploding goo bombs pushed schemes for freezing cymatics to the back-burner, and I started Googling around excitedly, seeking the inevitable YouTube video that would show me exactly what an “explosive polymerization” looked like, and if it was as exciting as it sounded.

As far as I can tell, they’re aren’t any.

Moreover, textual information in the tubes is scanty. The phrase appears in the abstracts of a few articles in polymer science journals, and in safety warnings associated with certain chemicals that are prone to explosively polymerize and with those that are prone to initiate the process. (Including some safety nightmares that are in both categories.) Inevitably it’s considered as, you know, a bad thing. An uncontrolled, useless, and probably dangerous process to be avoided if at all possible.

And I’m sure that’s all true. But it sounds really neat. And I want to see it.

I mean, taking proper precautions, I can set off a firecracker or other small conventional explosive, film it, show it off to others, and generally have a good time learning something about the natural world. And even though I’ve got a graduate degree in organic chemistry, I know comparatively little about polymers, and I’m not about to start experimenting without advice from somebody who knows what from what-not.

So I’m crowd-sourcing the problem. Is there a specialist in the house who knows something about explosive polymerization? And if so, can you tell me: What is the polymerization analog of a small firecracker? Some kind of diminutive goo-bomb that will go off impressively but without injuring bystanders or spraying horrible toxins everywhere? I mean theoretically, of course. I can’t promise to actually do anything unless I can satisfy myself it’s really safe, but maybe somebody can point me in the right direction?

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.


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Comments

  1. Michael Una says:

    I had similar thoughts about trying to freeze a cymatic wave. I did some experiments using plaster, but was dissatisfied with the results for a number of reasons.

    Did you ever find any fast-crystalizing plastics?

  2. Rick says:

    2 thing come to mind.
    1. Borax added to PVA glue will cause fairly fast polymerization – the amount of borax effecting the speed.

    2. There are thermo plastics – trade name Polymorph in the Uk (shape lock is similiar on the USA market) that set rigid at around 2 deg C and reflow at around 6 deg C

  3. Gaze says:

    Explosive polymerization is just another name for highly exothermic polymerization. Some stuff crosslinks but really what you get is an explosion. Experienced chemists aren’t talking because you’re gonna hurt yourself doing this.

    Here’s the deal, when something crosslinks, bonds are formed. When bonds are formed, energy is released due to the product being more favorable… in other words, you could take the energy released and somehow put it back into the system to break the bonds back up, and thermodynamically energy is conserved. Crosslinking a polymer involves a shit TON of bonds being formed. Notice that fast curing glue gets kinda warm… over a few seconds. If you want something to solidify FAST, you’re making a lot of bonds FAST and releasing a ton of energy FAST. It’s very very dangerous. Notice how most of your google results are safety handbooks saying “don’t mix this or that or you will be very unhappy.”

    If you wanna see something make a very quick phase transition, read up on supercooling.

    1. Sean Michael Ragan says:

      While I appreciate your concern for my safety, I would emphasize that I’m not a newbie when it comes to running potentially dangerous reactions. I’ve got a graduate degree in organic chemistry and 5 years of bench synthesis in both academic and industrial labs. But my polymer chemistry is limited to the usual undergraduate “snot” labs, so I wanted to hear from a true specialist, if I could find one.

  4. Sijesh Mad says:

    Sounds interesting. I think to get the desired effect as shown in youtube, you might need to go for fast curing resin. Also, you might need to add some shear thickening additive. try using 100% solid resin(low MW) as presence of solvents might delay the curing. I could think of
    - (as suggested by rick) PVA + borax or gluterdialdehyde reaction . Also add some methyl cellulose (HEMC) to it.
    - radiation cure polymers with short gel time. I’m wondering if there is any sound activated reaction?
    - usual polyurethane reaction with excess tin or secondary amine catalyst.

  5. RW says:

    I’m not going to name names, however, If they may be reading Make, perhaps they could shed some light on the subject.
    My late Father showed me examples of “explosive polymerization” years ago. He was a Research Scientist at Dow.

  6. failrate says:

    What about the stuff used in super-saturation hand warmers? That stuff solidifies immediately after being contaminated.

  7. Thor says:

    As an explosives chemist (for reals), I have an excellent starting point: acetylene under fairly low (under 100 psi) pressure, in the presence of catalyst. If you’re an O-chemist, that’s really the only lead-in you need.

    You could probably work out a fun way to do it with a nice, friendly epoxide like ethylene oxide or propylene oxide, but there’s a whole ‘nother level of early death layered on top of those. Stick to stuff that can only kill you once over for now.

    1. Sean Michael Ragan says:

      Thank you! That was exactly the kind of lead I was looking for. Cheers!

  8. Joshua A.C. Newman says:

    I’m wondering if there is any sound activated reaction?

    Epoxy speeds up its reaction when it’s agitated. I wonder if you could find an epoxy of the appropriate properties to make this work?

  9. bjr54 says:

    Methacrylates cured with a plasma arc lamp may be a good starting point. I know many dental cements can be cured in just a few seconds with one of these lights.

    You’ll probably only be able to cure small sizes (<10 mL); the sudden release of the heat of reaction can create enough thermal stress that the cured resin will shatter (or boil any uncured resin leading to distortion of the final product). Adding a filler (like fine quartz particles) will reduce the total amount of heat-producing resin in the liquid. The filler may also increase the viscosity of the liquid which could alter its cymatics.

  10. Fred says:

    I believe this is what you were looking for…

    1. Sean Ragan says:

      Magnificent! Thank you very much for letting me know.