Rosco Bodine
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Permanently Plastic Sulfur
Here's a strange one .
We all know about the temporary version of plastic sulfur .
But finding a way to cause the sulfur to remain plastic
is a pretty neat trick .
This material could have interesting possibilities as
a fuel and binder in pyrotechnics .
See column 4 line 38 for the brief mention of how
this permanently plastic sulfur is made using this
easily made organic sulfide polymer plasticizer .....
Attachment: US2429859 Sulfur Formaldehyde Resins and Plasticized Sulfur.pdf (490kB)
This file has been downloaded 623 times
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not_important
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Other materials can do the same thing. Styrene works, even polystyrene to some extend.
When you heat sulfur the S8 rings break open, giving diradicals. In a certain temperature range these tend to chain together to give longer chains of
S(n) diradicals. Heat the sufur enough and the chains start to fragment.
Those long chains are what make liguid sulfur so viscous, their breakage is why it becomes more mobile when heated near its boiling point.
Capping the chains so they are no longer radicals prevents reactions resulting in the reformation of S8 and other small rings. The rings still form
slowly by other mechanisms, but take much longer to happen than with reasonably pure sulfur.
You can see this when compound of the form Cl-S[n]-Cl are reacted with aquous base, the ionic Na+ -S... groupings function a bit like detergents and
sit on the outside of a ball made of long chains of sulfur, effectively liquid sulfur.
Unsaturated compounds such as styrene react with the radicals at the end of the chains, stablising them. I'll try to find my book on the physical
properties of sulfur, it had several chapters talking about this.
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Rosco Bodine
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I am looking at a condensation reaction product here and not just its applicability as a dispersant or emulsifier ,
although that scenario is interesting also .
This materials CH2S4 group is probably reactive as
such as a real compound and is alone more than simply being a homogenized colloidal suspension of S8 ring fragments ,where a matrix of unreactive
dispersant material would be employed as a polymerization inhibitior .
The substance could also possibly further react with ketones to form other condensates .
Acetone , MEK , and Ketone N ( see the triazone thread )were three which came to mind .
Anyway a couple of the ideas which came to mind immediately with regards to possible usefulness for plastic sulfur , is as a binder for rocket
propellant ,
and also for fuse which could be made as a hot melted extrusion which on cooling would be like a rubber cord made of " rubberized gunpowder " .
If you have some good reading material concerning sulfur ,
please do share it .
Here's a copy and pasted excerpt from an artificial turf patent US4012545 where a plastic sulfur based adhesive is used for the backing to secure
polypropylene fiber .
Plasticized sulfur has been disclosed in various references, for example by J. I. Jin in "Chemistry of Plasticized Sulfur", Petroleum Division, A.C.S.
Symposium, Vol. 19, No. 2, March 1974, pp. 234-241, and by C. Kinney Hancock in "Platicized Sulfur Compositions for Traffic Marking", Industrial and
Engineering Chemistry, Vol. 46, No. 11, November 1954, pp. 2431-2435. Exemplary patents disclosing plasticized sulfur include U.S. Pat. Nos.
3,316,115, "Marking Composition"; 3,434,852, "Plasticized Sulfur Compositions"; 3,447,941, "Sprayable Sulfur Road Marking Compositions"; 3,459,717,
"Sulfur-Based Plastic Composition"; 3,560,451, "Plastic and Nonflammable Sulfur Composition"; 3,453,125, "Plasticized Sulfur Compositions"; 3,674,525,
"Plasticized Sulfur Compositions"; and 3,676,166, "Plasticized Sulfur Compositions". Also, U.S. Pat. No. 3,823,019 discloses plasticized sulfur
compositions.
[Edited on 8-2-2007 by Rosco Bodine]
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Sauron
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@Roscoe, that is quite neat.
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chemoleo
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I agree, well cool, never heard of it.
So the formula is CH2S4- what does it really look like? [SSCH2SS]n? Ah, probably rather [SC(SH)2S]n. So lots of sulfhydryls?
What happens if this rubber is pyrolysed? I could imagine CS2 might form- which is currently discussed elsewhere... Would be an interesting experiment
to try! Perhaps in the presence of a metal such as Al to form Al2S3 (to mop up extra S) - question is, what happens with the leftover Hydrogen? How
about oxidation of the rubber, with i.e. K2Cr2O7- wonderous things could come out of it, or just SO2 and CO2 
Or, how about chlorination of this rubber?
THis rubber could be an easy route to organic thio compounds!
[Edited on 9-2-2007 by chemoleo]
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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Ozone
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@ not_important, check out thiol-ene polymerization whereby a radically mediated polymerization operates via step kinetics. Think chain transfer
polymerization. These polymers might be compatable with S8, although, to my knowledge, this has not been attempted.
In fact, it seems quite possible that elemental sulfur, in-situ, may actually participate in the chain transfer to yield a thiol-ene-co-sulfur
block-type copolymer. Cool.
I got some papers on this for a cume a while back, and I will post them when I get to work (which is where my laptop, with the files on it is
located).
Cheers,
O3
[Edited on 9-2-2007 by Ozone]
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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