Why Johnsons Creek clogs atomizers

[Schroedinger's cat]

The mixing could be the main problem, but Bertrand is saying that PG has often been contaminated with PO, according to the book in which he found his info. Another thing I'd like to know is whether, in the presence of PO, one would always get the polymerization in a visible manner.

Edit: Bertrand beat me to it....

[Bertrand]

Another thing I'd like to know is whether, in the presence of PO, one would always get the polymerization in a visible manner.

Yeah. It seems that it needs fairly specific conditions, since I couldn't reliably replicate it. And probably you need a decent concentration of it, too. It's unlikely that *all* PG is contaminated to a sufficient degree. Perhaps some separation occurs (they have radically different boiling points, and presumably differ in other ways) so that perhaps if you pull the stuff off the top, you get the PO, if you pull the stuff off the bottom you get PG. The more I learn, the less I want to know... hehehe

Propylene oxide won't do it alone, which is why people unfairly blame it on JC. According to the wikipedia article for polypropylene glycol (the polymer produced by propylene oxide), "With a multifunctional initiator like glycerine, pentaerythritol or sorbitol the polymer branches out."

[Schroedinger's cat]

So, in the presence of polymerization, one could be pretty sure that there is PO around. If no polymerization occurs, however, there could still be some PO contamination. It could be either that one step is missing to trigger the reaction, or that the amount of PO is too small to trigger it. Did I get this right? If this is the case, PG should really be replaced by VG by the manufacturers.... Where is a chemist when you need one?

By the way, what is the B&H you are back on? Regular tobacco? I take it that your mild concern has evolved further, if that is the case....

[Silver]

Hi all,

I've been in contact with Dr. Laugesen by e-mail before. Would you like me to bring this thread to his attention ?

Cheers,
Silver

[Bertrand]

That's about right. Scary. Especially since none of the saftey researchers on ecigarettes appear to have looked into the production methods of PG in any detail. The original article regarding PO contamination is this one:

Kagan, M.R., Cunningham, J.A., Hoffmann, D.
Propylene glycol. A precursor of propylene oxide
in cigarette smoke. 53rd Tobacco Science
Research Conference, Abstract #41 and #42,
1999

Well, not quite - obviously you want the article, rather than just the abstract, but that's how it is cited in the book.

I couldn't find it online, (only citations to it) but the source sounds credible enough, and I can't see them having increased safeguards on PG manufacture since then.

While I probably won't use any PG-based liquid any more, I intend to get some to send to a lab, assuming differential testing for PO isn't too expensive. If I'm right, this is deadly, and I don't want to look back and say to myself, "yeah, I really should have followed up on that one."

Unfortunately, the news, if it comes, can only be bad: a negative result would only mean that particular batch is okay.

B&H = Benson & Hedges. Yes, my mild worry got upgraded, but I'm trying not to be alarmist. Once I clean out the atomizers and cartridges (and get over my shock) I will possibly return to JC NPG.

[Schroedinger's cat]

I definitely think we need some expert opinion here, and Dr. Laugesen is an expert, and also has contancts with chemists. It seems a good idea to ask him.

Here is what the EPA has to say about propylene oxide:
Propylene oxide | Technology Transfer Network Air Toxics Web site | US EPA

[Silver]

I agree and am in the process of preparing an e-mail to him as we speak...

Cheers,
Silver

[Schroedinger's cat]

I don't know enough about chemistry to even try to figure this out. However, if someone is able to delve into this, there is a whole dissertation about how to obtain PO from PG here:
http://edt.missouri.edu/Fall2007/The...7/research.pdf

Alternatively, the abstract (and the link to the whole thesis) can be found here:
Electronic Thesis and Dissertation Archives - University of Missouri - Columbia

Thank you, Bertrand, for this (although I hope it turns out to be not a major concern...), and SIlver, for contacting Dr. Laugesen.

[Silver]

The e-mail with a link to this thread has been sent. I will let you know if I receive a reply from Dr. Laugesen.

Cheers,
Silver

[Bertrand]

Thanks, Silver. While I am likely wrong about the mechanism behind the goop formation, I am now practically certain that e-liquid and cartridge liquid is often contaminated with PO.