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Topic: Dissolving cured polybutadiene  (Read 2887 times)

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Offline Raynor105

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Dissolving cured polybutadiene
« on: April 12, 2018, 12:43:46 AM »
Greetings knowledgeable chemists. I have a problem that I was hoping we could solve. I'm not a chemist, just a technician.
Here is the problem: We used this potting compound called polybutadiene to fill in a protective shell containing a battery and electronics. Polybutadiene has good electronic properties so that the circuit would work after curing. Anyways, the project basically failed and now we have all of these shells with batteries inside this rubber like compound. In order to dispose of these failures, we have to get the batteries out. The question is, what chemical dissolving agent would be safe enough to dissolve the polybutadiene and not the battery? Any help would be greatly appreciated.

Offline P

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Re: Dissolving cured polybutadiene
« Reply #1 on: April 12, 2018, 06:23:21 AM »
Can you physically cut the batteries out from the rubber?

Regarding solvating the rubber - it will depend upon how cross linked it is as to whether it is even possible. The curing process causes a lot of x-links which strengthen it's resistance to solvents. It might no even be possible if cured right off. I am not sure what solvents work on cross linked polybutadiene rubber....  THF maybe?

If you find a solvent that supposedly works, you may need to let it soak for a few days to let the solvent soak right into the rubber - it can take ages if a polymer has a high degree of x-linking, which it probably will have if it has been cured off.  Before soaking in the solvent,. score the rubber up as much as possible - physically cut it and rough it up with a scalpel and or some sand paper. This will increase the surface area and make it easier for the solvent to attack deeper into the polymer. 
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Offline P

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Re: Dissolving cured polybutadiene
« Reply #2 on: April 12, 2018, 06:55:40 AM »
PS  -  If the solvent doesn't work straight away then leave it a few days like I said  -  although it might not dissolve it, it might soften it enough to make physical removal easier.
Tonight I’m going to party like it’s on sale for $19.99!

- Apu Nahasapeemapetilon

Offline Enthalpy

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Re: Dissolving cured polybutadiene
« Reply #3 on: April 12, 2018, 03:07:03 PM »
Potting electronic circuits is generally a bad idea. It prevents cooling by air, so the components burn from every small power loss. I did it once.

Even if you find some sort of magic solvent that removes the inert polybutadiene but spares the more reactive compounds in the batteries and circuits, it uses to take weeks. You may prefer to use a cutter instead, and possibly rescue only the batteries and discard the electronic circuits which are now doubtful anyway.

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