# Solvent for tire rubber

I want to apply tire rubber on surfaces, for various reasons - including protection against water. I think of tire rubber, as it is so widely available - helping in reducing pollution (infinitesimally) at the same time.

I am interested in a solvent which will temporarily transform the tire rubber into a (viscous) liquid - in such way that after some time, when the solvent evaporates, the tire rubber becomes solid again.

I do not need any special properties of the new rubber, there will be nothing really safety critical. If it is similar enough to the original, it is good.

Ideally, the solvent should be easy to find and I should be able to buy it without any special permits.

Think of this:

• there are some granules of salt;
• I add some water - and get salty water;
• after some time the water evaporates and I get 1 block of salt.

Now, the salt is actually pieces of tire rubber, and the water is... what? :)

I searched on the net, and the only solvent I recognized was acetone. Does anyone have any experience with this?

• Carbon disulphide is used to dissolve rubber but it will not be easy to buy nor will it be easy to work with unless you have a laboratory. I appreciate that this doesn't answer your question but it will give you an idea of the difficulties you will encounter. – user1945827 May 16 '19 at 9:52
• :) Thank you for the heads up. I had a good feeling about it - being a difficult task. Of course, if you will find a way to make the difficulties less impacting, I will be happy. – virolino May 16 '19 at 10:08
• I think chloroalkanes would do the job though I don't have supporting info. Dichloromethane (aka methylene chloride) is the lightest and evaporates quickly. Chloroform and carbon tetrachloride are more toxic. – SteffX May 16 '19 at 14:59
• The environmentally friendly way to do this is shred or grind the tires to suitable sized particles and then mix them with a bonding material. No hazardous chemicals required, but you can't do it easily yourself. It is already done on a commercial scale (the product is called "crumb rubber") so disposing of your tire at a recycling site is just as good for the environment as doing something yourself. – alephzero May 16 '19 at 16:12
• Tire rubber is a crosslinked polymer. Doesn't really melt or dissolve as far as I know (depends on the degree of crosslinking). Crosslinked polymers can swell, but you might have trouble finding a solvent that fits your water/salt analogy. pslc.ws/macrog/xlink.htm – mcole May 16 '19 at 20:14

As it was mentioned in the comments, finished rubber is a cross-linked polymer, and this is the main reason why getting vulcanized rubber liquefied without destroying it seems to be a nearly impossible task. Also, there might be other additives, e.g. tires are most likely going to contain powdered charcoal, so that even though one can dissolve the rubber by destroying the cross-linking $$\ce{(-S-S-)_n}$$ bonds, charcoal is likely going to form another phase, and who knows what might happen to other additives during this process. Finally, at the end you have to somehow recreate cross-linking for the rubber to retain it's elasticity, and this doesn't happen on its own by just evaporating the solvent (see vulcanisation).