does pex contain bisphenol A?
national geograpic rercently had an article on toxins in the home. one mentioned bisphenol-A ,found in polycarbonate plastics like nalgene water bottles. the stuff may cause reproductive harm to fetuses, and lab animals. does anybody know if pex contains this stuff? thanks
Replies
No
To be more specific, PEX stands for PolyEthylene Crosslinked (X is shorthand for crosslinking among polymer chemists.). Normal PE will melt; PEX will not.
The cross linking can come one of two ways.
1. The compounder adds a chemical which under heat attacks the polyethylene molecule and causes it to link. These chemicals can be a bit problematic, as they must be rather agressive to attack polyethylene. Traces can also be a problem.
2. The tube is extruded from PE and then goes through a chamber which bombards the PE with (basically) static electricity. This energy breaks up the molecule and causes it to cross link. There are essentially no "nasty" molecules to leach out.
I don't know which is used for PEX, but I hope it is the latter. I could do some research, but I am too lazy tonight--did to much around the house.
There are 3, maybe 4 methodes. And the one does not use static electricity, but electron bomb bardment.http://www.sheltertech.com/wirsbo_pex_tubing.htm"PEX is an acronym for cross-linked polyethylene. The "PE" refers to the raw material used to make PEX (Polyethylene), and the "X" refers to the cross-linking of the polyethylene across its molecular chains. The molecular chains are linked into a three-dimensional network that makes PEX remarkably durable within a wide range of temperatures, pressures and chemicals.There are several different methods used to cross-link polyethylene. It is important to distinguish between the various methods of cross-linking and the PEX products that result. A distinction should be made between PEX produced above the polyethylene crystalline melting temperature, and PEX produced below that temperature. Simply stated, there is a difference between PEX that is cross-linked during extrusion and PEX tubing that is cross-linked in a post-extrusion process.Wirsbo uses the Engel method to chemically cross-link polyethylene during the manufacturing process when polyethylene is in its amorphic state (above the crystalline melting point). The Engel method provides more precise control of the degree of cross-linking resulting in a perfectly uniform product. There is no chance that areas of the tube will be unevenly cross-linked, and there are no weak links in the molecular chain. Engel Method PEX has what is known as shape or thermal memory. It is this thermoelastic property that gives Wirsbo PEX (Engel) its incredible flexibility, strength, and high temperature/pressure resistance. The shape memory is also what allows the ProPEX Fitting system to work.The other two common methods of cross-linking PEX are the Radiation method and the Silane method. Radiation cross-linked PEX uses electrons that bombard the tubing after it has been extruded. Silane PEX uses a warm bath to cross-link, and then flushes the tubing to remove contaminants. Silane PEX is not as evenly cross-linked as Engel PEX, nor does it have the same degree of thermal memory."http://www.thermapextubing.com/whythermapex.aspI think that the A is the Engel and the B is the Silane, and C is irradiated.And the Thermoplex is the 4th method.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Absolutely correct in your summary. As I said, it was late. And, "static electricity" typically causes electrons to be expelled from the atoms. So, I used a sort of generic term to describe electron bombardment.
For that fact, I could have said that they used beta particle bombardment, making it sound like it was part of a radioactive treatment. And, I was tempted but there is enough of that sort of stuff around that people take too seriously.
(Remember the proposed ban on dihydrogen monoxide? It is a known fact that if you are exposed to an excess of this material you will die.) IT'S A JOKE. TYPE THE NAME INTO GOOGLE.
wow, thats a lot of PEX info!
you must know the answer to the whole peter piper picked a pack of pickled pex thing!
i never did get the answer to that one, but i do know that the woodchuck can chuck about 1/2 a chord a day.
oh and by the way, does pex have any bisphenol A in it?
it could be that PEX turns out not to be as safe as we think it is, but at this time there are only two types of tubing that are used for dialisis, stainless steel and PEX because they don't leech anything into the fluid they are transporting.
a few years back there was a polybutyl tubing made by shell i think. extensive testing was done and it was approved for use and installed in homes, then it started dissolving. the extensive testing didn't cover chlorine, and funny ha ha, they use chlorine to purify the water the polybutyl tubing transports.
of a greater concern i think is the new evidence that shows that saliva causes cancer, but only when swallowed in small amounts over a long period of time!
Here's a link to a BLOG that presents some info on which plastics contain BPAs. If this is accurate, then PEx does not contain BPAs.
http://www.shahine.com/omar/bisphenola.aspx