Talk:Polyethylene

From Academic Kids

Is polyethene the same as polythene? If they're the same, we should said so; if they're different, we should say "not to be confused with..." --Camembert

well, they are different words that refer to the same substance, polythene being the British usage. (Abbey Road and all that... ) --- Someone else

acording to my Penguin Dicitonary of Science, Polythene is aslo called Polyethylene. it doesnt mention polyethene. But it sounds to me liek there's a difference -- IIRC polyethylene keeps its -OH groups. -- Tarquin

Oops, youre right, my eyes inserted an '-yl' where there was none! Polythene is Polyethylene, but the title of the article is polyethene. Converting to "Not to be confused with!" though I'm not sure all three aren't the same... the illustration on our Polyethylene article seems to depiect the same molecule as the Polyethene. Could just be a third variant word??? -- Someone else

Hm. I was werong about keeping the OH -- see http://www.psrc.usm.edu/macrog/pe.htm. So it does look like all 3 words are the same thing: a long chain of C with 2 H for each C. -- Tarquin

Seems so - if you search for "polyethene" on xrefer (http://www.xrefer.com), it comes up with a stack of results saying that "polyethene" "polyethylene" and "polythene" are all the same thing. Looks like merging is in order, preferably by somebody at least a little bit less ignorant than me ;) --Camembert

I nominate Tarquin. He has a Dictionary of Science<G>. Sadly, none of the three words seems to be in the OED. -- Someone else

Eek! I have a welsh-english dictionary too, but I don't speak a word of welsh ;-) Anyway... reading both those articles, it turns out I was wrong about "ethylene" too. Enthylene is just an old name for ethene, not (as I thought) the ethyl alcohol, which is of course (slaps self), ethanol. (I ought to know, I drink enough of it ;) So merging is indeed in order. I'll have a stab at it -- Tarquin 14:35 Dec 1, 2002 (UTC).

All the times i have seen the Resin identification code tehy always use polyethylene -fonzy

---

Polyethylene is by far the most common name of the stuff, and that's not just in the US. Google test:

• Searched the web for polyethylene. Results 1 - 10 of about 645,000. Search took 0.08 seconds.
• Searched the web for polyethene. Results 1 - 10 of about 2,400. Search took 0.48 seconds.
• Searched the web for polythene. Results 1 - 10 of about 79,300. Search took 0.07 seconds.

Mkweise 21:14 Apr 28, 2003 (UTC)

If my memory is to be trusted, the difference goes back to one major chemical giant developing it under the name "Polythene" and a competitor, unable to use that trademarked name, calling its own more-or-less identical product "Polyethylene". (It might have been du Pont, followed by Union Carbide, but don't trust that last bit without checking it.) One imagines that the second firm had a larger market share in the UK, and that the Brits loyally used the term that their own company used, but this last is pure speculation on my part. Tannin

Contents

1 Useful life 2 Too technical 3 Trivia 4 Hello everyone 5 how strong is it ?

Useful life

Has there been any studies or observations to determine the useful life of HDPE?

How safe is it?

If a polyethylene tank is used to store rain water for drinking is there any danger of the chemicals, used to produce the polyethylene, contaminating the drinking water? How much safer is polyethylene to store rain water for drinking than concrete or galvanised iron?

High Density PolyEthylene (HDPE) and PolyEthylene Terephthalate (PET or sometimes PETE) are these days the two most common plastics used for food and beverage bottles and other containers. Gallon-size plastic bottles of drinking water and gallon and smaller plastic bottles for milk sold at grocery stores are most commonly made of of HDPE, often with Low Density PolyEthylene (LDPE) caps. My conclusion is that, practically speaking, polyethylene and PET are as safe as any economically available materials for food, beverage, and water storage. If you're worried about ethylene (raw material to produce polyethylene), ethylene is a volatile gas which in small quantities is present naturally in plants as a ripening hormone. Ethylene is also used in the fruit/vegetable industry to help ripen already-picked tomatoes, etc.

I suspect we will see a day when pipes for water mains and similar water supply pipes will be replaced by either plastic pipes or pipes with plastic interior lining to minimize corrosion and interior scale buildup. A potential problem with using concrete or similar materials for water storage tanks or lines is gradual leaching out of calcium and/or magnesium carbonates into the water, making it hard and giving it a stony flavor, but not making the drinking water dangerous. Use of metals for storage containers and lines could potentially introduce traces of oxidized metals into the water, but this is mitigated by galvanizing the interior of steel or iron containers so that the zinc acts as a sacrificial anode preventing oxidation of the iron. Traces of iron salts in water are not very detrimental, but could impart a bloody flavor to the water.

Regarding the useful life of HDPE; although HDPE is relatively chemically inert and does not bond well to any material, its useful lifetime when used in plastic bottles could be limited if the HDPE bottles are dented or deformed. When the fairly thin flexible wall or "sheet" material is bent such that a crease is created, the polyethylene "sheeting" right at the point where the crease is formed, is most susceptible to the formation of microcracks within a week or so. Within a few weeks, the crack can grow into leak rendering the container unsatisfactory. Dents in thin-walled polyethylene containers are to be avoided for this reason. Over the course of many months, even slight dents in empty thin-walled HDPE containers can render many of them leaky. This observation comes from my personal experience. H Padleckas 22:47, 15 Jun 2005 (UTC)

Too technical

The last paragraph of this article is too technical for most readers to understand. Can someone rewrite it to make it more accessable to non-experts? Kaldari 21:23, 2 Feb 2005 (UTC)

I disagree - it's no more technical than the preceeding paragraphs, and in the end this is a technical article. Iridium77 20:17, 10 Feb 2005 (UTC)

Trivia

During World War II the British used polythene as an electrical insulator in their radar equipment and the Germans, being unable to make it themselves, could only obtain polythene from crashed RAF aircraft.

Hello everyone

Hi, I am a grad student at Case Western Reserve University. I am working on a Master's degree in Macromolecuar Science and Engineering (Polymer Science). It seemed like this page could use the touch of someone with some knowledge of the polymer field. I have made several changes based on what I have been taught in my education. If you would like to double check on these facts, please see the Macrogalleria website[1] (http://www.pslc.ws/macrog/index.htm). I will come back in the next few days and create some pages to go with the links I've created. Thank you everyone. --Scipantheist 18:31, 29 Apr 2005 (UTC)

how strong is it ?

"UHMWPE can be used to make fibers which are so strong they replaced Kevlar for use in bullet proof vests."

"scientists say the polyethylene molecules that make up the fibers of Dyneema are 15 times stronger than steel." Spectra

How strong is polyethylene, in GPa ? --DavidCary 17:35, 4 Jun 2005 (UTC)

Is there a particular example of UHMWPE that you want to find the strength for, say Dyneema? I ask this because the strength of a polymer is highly dependent on its molecular weight, branching, and a host of other properties (which the article does not address at the moment). The question "how strong is polyethylene, in GPa?" isn't really specific enough for a precise answer. HappyCamper 18:04, 4 Jun 2005 (UTC)