Talk:Polyethylene

Oxo-Biodegradable (OBD) Polyethylene??

I noticed there is a section about 'Ecological problems' but I don't think it provides sufficient information. Shouldn't there be more information about biodegradable and oxo-briodegradable polyethylene (pros/cons), especially since the main concern regarding polyethylene is it's effect on the environment?

Also, there is no mention of the effects on health. Since, as mentioned, PE is mostly used for packaging, some of which comes into food contact, shouldn't the accusations of PE transfering cancerogenic chemicals into foods and beverages be addressed?

I don't know, just wanted to see if anyone else is on the same page. —Preceding unsigned comment added by Marylee D (talk • contribs) 06:16, 18 May 2011 (UTC)

Miscellaneous

Added definitions for MDPE, VLDPE and corrected some errors (MDPE is not = LLDPE). I apologize in advance if I stepped on any toes, I am fairly new to Wikipedia. The area of PE however, is not new to me. I worked as a researcher in the area for a number of years for a top producer and technology licensor and even have a few publications and patents to my name. --Dwdockter 22:29, 18 November 2005 (UTC)

Cross linked polyethylene is also commonly referred to as "XLPE", in fact I've heard this used far more often than "PEX". SM 29/8/08

The cross-linked polyethylene page notes that as well, however it uses the PEX abbreviation throughout the page. --Wizard191 (talk) 15:58, 29 August 2008 (UTC)

Dwdockter, as someone who has expertise in polyethylene, would you please check my remarks under "Useful life" below in this Talk page? Has the microcrack "problem" been studied or documented anywhere? Thanks. H Padleckas 06:55, 19 November 2005 (UTC)

The problem you are referring to is called stress cracking and would be a problem for the combination of resin structure and the stabilization package seen in most Dairy Resins (i.e. Milk Jugs). However, this problem is usually solved by moving to a HIC (Household & Industrial Chemical) Resin. I would not recommend storing drinking water in containers previously used to hold laundry detergent, bleach, or drain cleaner (I guess if you wash them with enough hot water, eventually...theoretically... but I digress). However, most orange juice containers are made of the same material. Why are milk jugs made of a PE with a stress cracking problem? It's cheaper. Furthermore, milk does not have the stress cracking problem because it is a nearly neutral material and contains no surfactants. Both contribute to stress cracking. Plus the expected life of a milk jug is a few weeks and it spends most of it's life in a cold dark place. Heat accelerates stress cracking. --Dwdockter 00:26, 6 December 2005 (UTC)

Double bond?

I have a question. When I look at the insert for the repeating unit for ethylene, it shows only a single bond between the two carbons when I think it should be a double bond, and each carbon has two hydrogens, when each should have one. Carbon forms four bonds doesn't it. And you wouldn't have stereo-chemistry with a single bond between the carbons because a single bond would rotate. —Preceding unsigned comment added by 74.93.205.118 (talk) 14:24, 31 July 2008 (UTC)

Polyethylene is formed from ethylene, which does have a double bond between the two carbons. It is because of the presence of this double bond that the chemical reaction can occur whereby many ethylene units link together to form polyethylene. The repeating unit that you mentioned is not "ethylene", it is simply a representation of how the remainder of the ethlyene molecule looks once it has undergone reaction and become part of the polyethylene chain. SM 29/8/08

Name of this material

Polyethene versus polyethylene versus polythene versus ...

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 Dictionary of Science, Polythene is also called Polyethylene. it doesn't mention polyethene. But it sounds to me like 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 depict the same molecule as the Polyethene. Could just be a third variant word??? -- Someone else

Hm. I was wrong 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, 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 they 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)

Caution: see WP:SET. —DIV (128.250.80.15 (talk) 06:05, 7 January 2009 (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

Correct, it is pure speculation. Polymers are normally named as the "poly" of the monomer used, in this case ethylene. Thus polyethylene is the more commonly used. Polythene appears to be an alternate nomenclature word that has held on in the UK. Much like thiol vs mercaptan --Dwdockter 22:12, 18 November 2005 (UTC)user:dwdockter

For all chemicals there exists a list of various names. To make life easier for chemist and other scientists IUPAC has developed an international standard nomenclature for chemicals. Most new teaching books in chemistry use the IUPAC nomenclature for naming chemicals. Nevertheless, many people in the industry like to use other less systematic names as for example polyethylene. The correct IUPAC name is polyethene and this ought to be the name of the article with polyethylene redirecting to this one.

Strongly agree with this last comment: 'polyethene' is the correct scientific name. The derivation comes from the prefix 'poly-' and the monomer name 'ethene'. The confusion comes because the traditional name of the monomer is 'ethylene' (hence 'polyethylene'). As far as I was aware 'polythene' was a commercial name — in any case it has no scientific standing. On the other hand, it makes no sense for either 'polyethene' or 'polyethylene' to be trademarked: this would be like trademarking 'milk' or 'paper' (I'm not saying it couldn't happen, though...). 'Polyethene' should be the name of the article: we should not be deferring to what "Google says".

— DIV 128.250.204.118 00:02, 5 January 2007 (UTC)

A few more details...

Polyethene is the accepted scientific source–based name. The accepted structure–based name is 'poly(methylene)'. The difference is due to the opening up of the double bond upon polymerisation. I also quote IUPAC. {A Guide to IUPAC Nomenclature of Organic Compounds, Blackwell Scientific Publications, Oxford (1993).}

The name “ethylene” [can] be used for a divalent group, “–CH2CH2–” only and not for the monomer, “CH2=CH2”. The latter is “ethene”.

I will add to the introduction.

— DIV 128.250.204.118 00:12, 5 January 2007 (UTC)

"Ethene" is the official IUPAC name for the monomer which is commonly known as "Ethylene". However, nobody except school chemistry teachers and their pupils ever uses the name "ethene", just as nobody except school chemistry teachers and their pupils ever says "propan-2-ol" (everyone else says "IPA"). Therefore the polymer is always referred to as "polyethylene"; "polythene" is just a shortened, slang-ish name for it. SM 29/8/08 —Preceding unsigned comment added by 217.198.33.252 (talk) 12:35, 29 August 2008 (UTC)

'Good' example, as "IPA" = International Phonetic Alphabet (doesn't it?), whereas "propan-2-ol" is a chemical.  ;-)p All of the handy phrases used in casual discussion are brilliantly convenient ...but not necessarily the best basis for encyclopædia articles.

—DIV (128.250.80.15 (talk) 06:07, 7 January 2009 (UTC))

poly(methanediyl)

On 08 December 2008 User:71.231.158.201 made a change in the Description described as IUPAC name edit per 2001 Purple Book. The change was inserted before the citation I added earlier to the recommendations published in 2002 by KAHOVEC, FOX & HATADA, which is misleading, as it does not appear there.
The only reference to this name that I have is in the 2005 IUPAC Provisional Recommendations for the Nomenclature of Organic Chemistry. They make it clear that they intend to prefer "methylene" over "methanediyl". (See pp. 500 and 1292 [p. 18 of Appendix 2]). I have made the correpsonding changes.
There is also a 2008 version of the IUPAC Purple Book, which I don't have; anyone who has a copy may care to verify its recommendations. —DIV (128.250.80.15 (talk) 04:17, 6 January 2009 (UTC))

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 a 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)

polyethylene pipe industry (subset of polyethylene industry) has conducting studies regarding useful life of polyethylene pipe. See http://plasticpipe.org/municipal_pipe/water_publications.html for details. BluSkyy (talk) 15:33, 21 June 2011 (UTC)

I'd like to see the article add information about useful life and degradation of polyethylene. I've observed a number of polyethylene household articles turn yellow and brittle after 10-20 years, even stored away from sunlight in benign temperature conditions.  — Quicksilver^{T @} 23:35, 30 July 2011 (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.— Preceding unsigned comment added by 82.111.113.204 (talk • contribs) 22:34, 15 April 2005 (UTC)

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]. 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)

Huh?

An enormous amount of stuff is made of polyethylene and can be found nearly everywhere. Yet this article is far too technical for the non material science reader. Perhaps someone can use their material science education to make this article more broadly accessable.

If and when I get the time and energy to do it, I plan to add some applications information to this article. H Padleckas 03:39, 12 July 2005 (UTC)

RXF1

I don't know if this should be incorporated into the parent article or not, but I thought I'd mention it, just in case...

NASA scientists have invented a groundbreaking, polyethylene-based material called RXF1 that's even stronger and lighter than aluminum. [2] TerraFrost 01:38, 4 September 2005 (UTC)

Translation and then some...

I just finished one article in a Wiki for a ChemEng group at my college. It's in spanish, a professor has already told me I have a couple of errors, but in the overall its good. I wrote the article and also ported it to Freemind, I was wondering if the idea would be appreciated in the group? Take a look at the article, or at the mindmap, if you don't have Java, you can take a look at the image of the expanded mindmap.

Polyethylene Tanks for Chemical Storage

Im currently doing an investigation into the use of HDPE and XLPE for bulk storage tanks for Sodium Hypochlorite and Fluorosilicic Acid. Was wondering what the common practice was? Currently at my place of work, failures have occurred at fittings on HDPE tanks and conciquently leaked the hazardous material. I also know in Germany now they have banned the use of Polyethyene for Sodium Hypochlorite storage, however everywhere else in the world it is the recomended material?!?!?

Yes, I'm doing the same thing (also with Sodium Hypochlorite). Why there a chemical compatibility issue between different types of PE (for example: PE vs XLPE)? It's the same chemical makeup isn't it? dq 21:06, 21 March 2006 (UTC)

HS Classification

Hello, how would you classify LLDPE, based on the WCO with less than 95% monomer content or more than 5% olefin content? Thanks

Why so much on fireworks?

The paragraph on usage in the fireworks industry for HDPE seems a little much, given the depth of the rest of the article. Fireworks is neither the primary usage for HDPE nor of daily importance in people's lives. Seems like a "also used as mortar tubes for fireworks" would be (more than?) enough. Acertain 19:43, 6 September 2007 (UTC)

Image request added

 Done

I added a request tag for a photo (or some photos rather). We should be able to present some easily recognizable products made with this material. __meco (talk) 11:43, 6 June 2008 (UTC)

Very hard to glue

Could add some information on heat welding and gluing it. —Preceding unsigned comment added by 69.154.214.35 (talk) 18:07, 18 April 2009 (UTC)

I've added a joining section. Wizard191 (talk) 01:44, 19 April 2009 (UTC)

IMO joining should include heat fusion or butt-welding as it is the most common way of joining polyethylene pipes.70.183.40.99 (talk) 16:40, 28 January 2011 (UTC)

Health issues

What about health issues? The Lennon/McCartney song Polythene Pam makes mention of real-life Liverpudlian Pat Hodgett (now Dobson) from their Cavern Club days who regularly ate polyethylene. --79.193.43.100 (talk) 17:58, 2 December 2009 (UTC)

Environmental Issues

The Environmental Issues section ends with part of a sentence:

Polyethylene is not

However it finishes at this, did the autor of this piece mean to finish this, or should it just be deleted?

Neuphin (talk) 17:50, 17 January 2010 (UTC)

Disambiguation of "paraffin"

Regarding "When incinerated, polyethylene burns slowly with a blue flame having a yellow tip and gives off an odour of paraffin", this word means "paraffin wax" in some English-speaking countries, and in others a fuel distilled from petroleum that is called "kerosene" in areas other than the UK and South Africa. Any idea which is meant? The cited website does not make this clear either; I am going to try contacting those authors. mcgees.org (talk) 05:50, 1 December 2010 (UTC)

Probably referring to the UK usage - i.e., kerosene, as that was what used to be burnt in 'paraffin lamps' and similar, and was readily available in the shops before everyone got electricity. —Preceding unsigned comment added by 86.112.65.22 (talk) 11:13, 1 March 2011 (UTC)

Oxidisation of Polyethylene

Does anyone know whether this happens or not? 82.36.181.113 (talk) 22:34, 9 November 2011 (UTC)

Answer Thankyou User:Vespine 82.36.181.113 (talk) 05:38, 10 November 2011 (UTC)

Where is the Chemical Infobox

Like polypropene has? — Preceding unsigned comment added by 108.69.248.199 (talk) 08:04, 29 November 2011 (UTC)

Is polyethylene an alkane?

I am not a chemist, but I can see there are some similarities between polyethylene and the class of compounds called Alkanes. Should the article make this connection explicit, or is that the wrong interpretation? — Preceding unsigned comment added by 128.112.139.195 (talk) 22:26, 27 February 2012 (UTC)

Edit request: nonsensical passage

Under the sub-heading, Ultra-high-molecular-weight polyethylene (UHMWPE), the passage "These include can and bottle handling machine parts..." doesn't really make sense. I'm not certain what the intent was, but it needs to be fixed. 65.199.212.7 (talk) 19:55, 17 September 2013 (UTC)