Talk:Polystyrene/Archive 1

Expandable?

The foam section describes expanded and extruded forms, but then mentions expandable. Needs clarification. --Thatnewguy 13:27, 14 May 2006 (UTC)

Styrene

I deleted the phrase saying styrene is also found in plants. The fact that styrene is found in trace quantities in plants is of no significance to polystyrene, a plastic artificially manufactered in bulk quantity. H Padleckas 14:09, 26 Jan 2005 (UTC)

Health rsk?

I can't figure this out... is polystyrene a health risk... or not? and how big is that risk?

If you burn it, yes, it emits toxic fumes. If you melt it, it may or may not. I've heard yes, and yet hobbyists who build models from it routinely melt the stuff (or at least heat it until it becomes soft and pliable) as part of the modeling process, so I'm not so sure. I do know of people who refuse to buy any products packaged in polystyrene but I do not know why. We routinely eat with forks and spoons made of the stuff and we make children's toys out of it, so I suppose it depends on how you define "health risk." Obviously, as far as our current science can tell, it's safer than, say, lead. Dave Farquhar 20:35, 31 Mar 2005 (UTC)

I'm a bit confused about this too. It is definetly used in vacuum forming though. Perhaps only in well ventilated areas? I am a lemon 05:07, 22 August 2007 (UTC)

Dissolve, not Melt

It states under dangers that acetone melts polystyrene. This is untrue (though often said) as the acetone dissolves the polystyrene. I have changed the article accordingly. --144.132.85.218 01:44, 3 January 2007 (UTC)

Styrofoam

Yes it's a trademark. It says it's a trademark in the text. You don't need to insert some copy-paste from a company brochure to highlight that it is a trademark. Merely stating that it is a trademark is enough. Whatever Dow is paying you, it's too much. Work a real job for a living. Howdoesthiswo 23:12, 21 November 2006 (UTC)

If no one can come up with a suitable reason, I'm going to make styrofoam into a redirect here, as that page has very little information, and people will prbably want to read this page. —ScouterSig 00:40, 19 January 2007 (UTC)

Polystyrene and CFCs

Polystyrene foam packaging products in the United States doesn't contain chlorofluorocarbons (CFCs) since 1990. Most polystyrene foam products never were made with CFCs

Unicode for resin identification

This was deleted from the article by an anonymous editor, but I wanted to save the information for any interested party: "The Unicode character is &#9848, which will appear here if you have a suitable font installed: ♸."

I attempted to revert the Unicode back-in last evening, but it didn't "take", so I'm trying it again this morning (US time). If it still doesn't work for me, then you should try reverting the page.

Atlant 11:53, 4 August 2005 (UTC)

Polystyrene

i'm quite confused that Polystyrene has so many types such as High Impact PS, General Purpose PS and Oriented PS. what is the difference ?

The nature of high impact PS is explained in the section polystyrene#Toughening; it's chemically different, and also has quite a different microstructure. Oriented PS has been "pulled" so that its molecules tend to lie up in one direction, a little bit like oriented strand board but on a much smaller scale. It has anisotropic mechanical properties (e.g., it's stronger in one direction than in others). Note that ABS plastic (in drain pipes and electronics cases, for example) can also be considered a class of polystyrene. For even more info, see the Macrogalleria.--Joel 06:17, 5 October 2005 (UTC)

Percentages: blowing agent vs. polystyrene

Please check the percentage of blowing agent vs. percentage of polystyrene under the "Solid foam" section.

I believe the current statement is reversed (saying 5% polystyrene, 95% blowing agent) - every MSDS I have read on EPS is about 93-95% polystyrene and 7-5% blowing agent.

Someone double-check me though - thanks. —Preceding unsigned comment added by Dietlein (talk • contribs)

I suspect the argument bubbles up because we're using different definitions.

Some are probably saying "by weight" or "by volume prior to blowing" and they arrive at 95% poly / 5% blowing agent.

Others are probably saying "by volume after blowing" and they arrive at 5% poly / 95% blowing agent.

Someone who actually knows the truth should just add the right qualifiers to the numbers so we can see what the percentages actually represent.

Atlant 20:30, 23 February 2006 (UTC)

Regularity of polystyrene

Just wondering if polystyrene always attaches the phenyl group on alternate carbons, or whether occasionally a styrene molecule aligns "backwards," and there are adjacent phenyls (and two adjacent CH₂'s). -postglock 06:45, 16 February 2006 (UTC)

Standard polystyrene is atactic, i.e. the phenyl groups are randomly placed around the hydrocarbon chain. However, the recently developed material called "syndiotactic polystyrene" (sPS) has the phenyl groups in perfectly alternating positions. As far as I know, sPS has been a commercial failure and Dow, the main producer, has abandoned it. - Hispalois 09:42, 21 May 2006 (UTC)

Thanks Hispalois, much appreciated! Do you think this information should belong in the main article itself, or is it a bit too esoreric for the main section? -postglock 10:18, 21 May 2006 (UTC)

Your welcome! I think the paragraph above would belong in the article if there were a section on the "chemical structure" of the product. As it is now, I do not know where it could fit in. By the way, I would like to write a full, separate article on sindiotactic polystyrene, but I am currently busy with other projects. Maybe in a few weeks? Hispalois 22:23, 31 May 2006 (UTC)

It's a bit late for this contribution, but there is a misconception to be corrected here. "Isotactic" "syndiotactic" and "atactic" refer to the stereochemistry not the regiochemistry of polystyrene. "Isotactic" "syndiotactic" and "atactic" polystyrene all have the phenyl ring attached to every second carbon atom of the carbon backbone.Silverchemist 19:58, 4 July 2007 (UTC)

Desired: styrofoam photo

http://www.weyerhaeuser.com/images/ourbusinesses/buildingmaterials/t6_DowStyrofoam_1.jpg

Styrene or benzene?

The chemical makeup of polystyrene is a long chain hydrocarbon with every other carbon connected to a benzene ring

Should this sentence be "... with every other carbon connected to a styrene ring." - How can there be a benzene molecule in polystyrene?

if i am just being stupid someone please point out my mistake...

This is a terminology thing. It's like saying polypropylene has a methane molecule on every second carbon: in fact, a methane molecule is free floating, and what propylene has is a methyl group. I'll change the article to say a phenyl group instead of benzene.--Joel 19:20, 26 April 2006 (UTC)

manufacturing polystyrene 1

does anyone know how they manufacture polystyrene? i would like to make one at the school lab and reinfoce some fibers for greater durability. thanks Styrene is a volatile liquid that is rather toxic; I certainly don't think any school in the US would allow such a chemical on the premises,or, to paraphrase J. P. Morgan, if you have to ask, you don't want to Cinnamon colbert 20:54, 1 October 2006 (UTC)

manufacturing polystyrene 2

does anyone know how they manufacture polystyrene? i would like to make one at the school lab and reinfoce some fibers for greater durability. thanks

pls do email me so. amparedes_17@yahoo.com

Squeak, squeak

Why is that damned noise so unpleasant? Bastie 23:30, 21 July 2006 (UTC)

I seriously think this article needs a section on adverse reactions to the sound it makes. —The preceding unsigned comment was added by 192.193.221.141 (talk • contribs).

EPS - Is it microwavable?

If an EPS foam is used between two layers of PP in a soup bowl product - can it be microwaved safely? I've been told that the EPS gives off hazardous chemicals when microwaved - but can find no documented proof - is this only a myth?

Product Developer 204.17.79.218 17:55, 25 September 2006 (UTC)

If EPS foam were heated to the point of pyrolytic decomposition, I suspect the breakdown products wouldn't be good for you. But food is rarely heated that hot and the EPS foam itself won't "heat" (dissipate energy) in the microwave oven. In any case, I have no qualms about eating food that I've reheated right in their EPS "take home" containers, although I try to keep the food from melting the EPS.

Atlant 18:49, 25 September 2006 (UTC)

Citations needed?

Citations neeeded--124.177.210.57 06:47, 22 November 2006 (UTC) citations are needed for all pictures

manufacturing process

Though I am not familiar with the details of the manufacturing process, I have the impression that the statement "The voids filled with trapped air give it low thermal conductivity" is not correct. Aren't the voids filled with "gas", i.e. the "gaseous blowing agent", and not with "air"? Wasn't this the reason that using CFCs as blowing agent was a problem? The CFCs were remaining trapped in the styrofoam and eventually being released to the atmosphere, rather than being sequestered in the manufacturing process. Can someone who knows more about what actually goes on in the factory comment on this? Piperh 10:41, 4 February 2007 (UTC)

"gay willys?"

Styrene can be copolymerized with other monomers; for example, divinylbenzene for cross-linking the polystyrene gay willys]]

I think this line not only looks and sounds unprofessional, it seems an obvious vandalism or joke. Kill it?  :) —The preceding unsigned comment was added by 66.75.161.29 (talk) 00:33, 13 February 2007 (UTC).

It seems that this has already been reverted. If something is so obviously vandalism (like this), I think that you would probably be better to revert immediately (without going to the talk page). See WP:RV for information on this. T23c 18:07, 15 February 2007 (UTC)

Density of PS

Looks like something wrong with the density of PS? On average it should be 1047 kg/m³ (1.047 g/cm³) Dj67 09:18, 20 April 2007 (UTC)

Well, this is Wikipedia, so you know what to do: be bold and fix it! You might want to check back through the article history, though, and see if this just isn't a case of "data vadalism" that you can undo/revert.

Atlant 12:22, 20 April 2007 (UTC)

Ahh, I see an anon editor just changed the units and some previous, uncaught vandalism changed the value; I've changed it all back to the earlier value of 1050 kg/m3, but if you want to make it 1047, please feel free.

Atlant 12:24, 20 April 2007 (UTC)

You sure about that 1047 kg/m³? That is more dense than water. Are you implying that styrofoam sinks in water? —Preceding unsigned comment added by 209.136.32.146 (talk) 21:54, 30 January 2008 (UTC)

"Expanded polystyrene" (a.k.a. "Styrofoam") is not the same as "polystyrene". The density of polystyrene is 1047 kg/m³. The density of expanded polystyrene, however, varies hugely from around 25 to 200 kg/m³ depending on how much air/gas was admixed to create the foam (200 kg/m³ is typical for surfboards). - Neparis (talk) 00:53, 31 January 2008 (UTC)

Synonyms?

Question, is Polystyrene the same as Styrofoam..? thanks. —The preceding unsigned comment was added by 88.108.231.79 (talk • contribs).

"Styrofoam" is Dow Chemical Company's trademark for their brand of polystyrene foam.

Atlant 23:15, 30 April 2007 (UTC)

I can not find information about UV-proofness of PS. Does anybody have data about capability to stand UV radiation and how is it to compare with PC and PMMA? Tiit tiitk@msn.com

microspheres

polystyrene microspheres (diameters from 100nm up to 10um or so) are used extensively in biochemistry, biophysics and elsewhere. for optical trapping applications the refractive index, n=1.59, is an important parameter. —Preceding unsigned comment added by 128.214.3.229 (talk) 09:42, 27 September 2007 (UTC)

Vaporized foam?

I don't think PS foam is vaporized when it comes near a hot wire. Instead the plastic bubbles in the foam burst and melt causing in the rapid reduction on volume that looks like melting. If no one objects in the next few days, I will delete the vaporizing foam part in the EPS section. Sjschen 17:31, 27 July 2007 (UTC)