Sciencemadness Discussion Board

BUTYL RUBBER from CAULK

Frontier9 - 15-8-2006 at 17:08

All of the so called BUTYL RUBBER (POLYISOBUTYLENE) caulks that are available at hardware stores actually have a BUTYL RUBBER content of less than 40% by mass. The most prevalent chemical in these caulks is Calcium Carbonate (Approx.: 58%), additionally these caulks contain Mineral Spirits (Approx.: 5%). Is there a not-so-sophisticated method of seperating and extracting the BUTYL RUBBER from these caulks?:)

DeAdFX - 15-8-2006 at 18:57

Yeah... Add enough hydrochloric acid to convert the calcium carbonate into calcium chloride. Dissolve all of the calcium chloride using water. Then filter out the butyl rubber. I assume that is all that needs to be done. I don't think the HCL should destroy the rubber.

kclo4 - 15-8-2006 at 20:51

if i may ask, what is so great about butyl rubber and why do you want it?

The_Davster - 15-8-2006 at 21:02

It is a binder. I believe the one used in c-4 plastique.

Anyway, I would like to add to DeAdFX's post, do do all of the procedure in a blender on 'puree'. Otherwise the caulk and butyl rubber wont react quick at all.

So add caulk to a HCl solution in a blender, let blend for a while, and then filter out the butyl rubber.

Ramiel - 15-8-2006 at 22:01

Yea right, and just how resistant is the interior of the blender going to be to [possibly] concentrated HCl... you'll want an excess of HCl anyway, so just add small amounts of "caulking glue" to HCl in a beaker or similar, letting it react before adding more.

Twospoons - 15-8-2006 at 23:56

It might be better to go the opposite direction and thin the whole lot with a solvent ( ordinary paint thinner?), let the carbonate settle out, decant off the solvent/isobutylene, then evaporate the solvent - leaving the isobutylene. I've done exactly that with some of the white goop plugging the end of a drainpipe under my kitchen sink. I used white gas (mostly hexane) as the solvent.
I think you'll have a devil of a time getting any aqueous reactions going - the stuff is made to be waterproof!


[Edited on 16-8-2006 by Twospoons]

Frontier9 - 16-8-2006 at 07:16

In response to kclo4, as rogue chemist states, Butyl Rubber may be used as a binder. Among other uses, it may be used as the binder in a solid rocket propellant grain.

12AX7 - 16-8-2006 at 14:07

Don't forget about rather inert TiO2, and that most blenders have a stainless steel blade -- you'll get a nice green soup and leakage, and not much pureed caulk.

Tim

The_Davster - 16-8-2006 at 16:31

Quote:
Originally posted by Ramiel
Yea right, and just how resistant is the interior of the blender going to be to [possibly] concentrated HCl... you'll want an excess of HCl anyway, so just add small amounts of "caulking glue" to HCl in a beaker or similar, letting it react before adding more.


Most blenders have a glass body, and stainless steel blades. Even with concentrated HCl(which is probably not needed) the blender would not suffer problems.

nitro-genes - 16-8-2006 at 16:39

Most caulking compounds contain curing or crosslinking agents, I'm afraid the butyl rubber version will not be an exception. Crosslinked rubbers do not dissolve anymore in solvents but will only swell at most. For an adhesive these are good properties of course, since it ensures a good chemical and mechanical resistance as the caulk cures...

There simply aren't alot of applications for low molecular weight, uncrosslinked rubbers, other than chewing gum, blue tac and a few others. One option than I haven't tried yet could be certain brands of those hotglue sticks. I have found in technical data sheets of some low melting temperature types that they contain mainly polyisobutylene and and a polyisobutylene/polyethylene copolymer. Since hotglue is remeltable after it cures it is likely that they contain no crosslinking agents...:)

[Edited on 17-8-2006 by nitro-genes]

unionised - 17-8-2006 at 09:20

Very few things rot stainless steel as quickly as HCl does.

Frontier9 - 17-8-2006 at 10:24

In response to nitro-genes, according to at least one manufacturer, the Butyl Rubber in sealants/caulks is soluble in naphtha. The following is an excerpt from their literature: Butyl Rubber Sealants sold today, including Red Devil Butyl Rubber Sealant will exhibit slight-to-severe solubility after a few hours in all grades of Naphtha; depending upon the extent of exposure to the solvent.

Butyl Rubber Sealants are typically a Butyl Rubber Mastic (Butyl Rubber cut w/ a grade of Naphtha to something in the 50% to 75% total non-volatile solids range), a mid-to-high molecular weight Polybutene, a solvent (typically a grade of Naphtha), some Titanium Dioxide (for white products; & TiO2 also improves durability), w/ the balance in Calcium Carbonate Filler.

quicksilver - 17-1-2007 at 17:02

IS there a source for polyisobutylene wherein the material is freely available without extraction? I found a source for a great many polymers (in the USA) but this one seems not to be used "as is". One time a fellow wrote that he had found same in a roofing coating. I did a search and found this (simple Google "polyisobutylene, source") but no outlet provider. Anyone found it? If you want to maintain the source; I certainly can respect that (please U2U me).

bio2 - 17-1-2007 at 17:56

....IS there a source for polyisobutylene wherein the material is freely available without extraction?......

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