Talk:Poly(methyl methacrylate)/Archive 1

Bullet resistant?/Riot control vehicles

Is acrylic glass the same as bullet resistant glass? There are a number of bullet resistant levels. Class I and II can be achieved with special acrylic products. Plexiglas product offering includes Plexiglas SB I and II, coated and uncoated for abrasion resistance. Both products are produced through a cell cast process achieving bullet resistant grade without requiring a lamination of any kind. There are other options manufactured by other acrylic manufacturers. (EMILIOJPEDRAL (talk) 00:23, 9 July 2008 (UTC)) Acrylic glass can also be a component of bullet resistant glass. It is laminated in between mineral glass or as the inside layer of such a laminate to protect the inside from shattered glass. Is there a reference for the use of acrylic for riot control vehicles?212.23.103.110 (talk) 15:58, 20 January 2008 (UTC)

No, see polycarbonate and bullet-proof glass. - Neparis (talk) 18:38, 20 January 2008 (UTC)

Plexiglas vs. Plexiglass?

Is it sold in the US as 'Plexiglas' or 'Plexiglass'? Currently only the double-s version redirects here. Psmith 22:21, 13 Oct 2003 (UTC)

The brand name is in fact Plexiglas with one s, but both spellings are common. I made a redirect from Plexiglas now so both spellings redirect here. Also, consider that both are trademarks property of Arkema Inc. therefore both versions are protected. Emilio Pedral 22:51, 08 July 2008 (UTC)

Transmissivity

I understand that glass does not permit transmission of Infra Red. What about Plexiglas?

It doesn't either. AxelBoldt 18:58, 25 Jul 2004 (UTC)

That's partially correct. I added a bullet point about this and an external link for more on transmission characteristics. --Ds13 17:24, 27 Jul 2004 (UTC)

Perspex? Trademark?

Where did the name "Perspex" come from? I had always thought it, like "Plexiglas(s)", was a trade name, but the article suggests otherwise. And is "perspex" really the most common name? I've most often heard it called just "acrylic", or PMMA (polymethyl methacrylate, I believe) in organic chem. — Danc 11:37, 10 Jul 2004 (UTC)

Perspex is a trademark of ICI just like Plexiglas is a trademark of another company , so I moved this article to the more neutral title polymethyl methacrylate. AxelBoldt 18:58, 25 Jul 2004 (UTC)

I believe ICI sold Perspex to Ineos Acrylics in 1999.

Atlant 22:56, 31 January 2006 (UTC)

As far as the USA is concerned, Perspex is a registered trademark now owned by LUCITE INTERNATIONAL UK LIMITED (originally registered by ICI).76.110.165.21 (talk) 02:52, 8 November 2008 (UTC)

Shiver me thermoplastics!

"PMMA does not shiver". What does this mean? Graham 00:09, 26 Jul 2004 (UTC)

It doesn't break or split into small pieces. AxelBoldt 21:47, 22 Sep 2004 (UTC)

Isn't that "shatter"? I've changed it accordingly. sjorford 14:41, 23 Sep 2004 (UTC)

I know this is an old discussion, but I've seen Plexiglas shatter before. Perhaps shiver had a technical meaning that was lost? — Scm83x ^talk 06:25, 20 February 2006 (UTC)

"Shiver" (crazing) happens when acrylic is glued with methylene chloride. The liquid is very volatile and cools significantly when evaporating. As it cools the surrounding material, the acrylic can crack parallel to the glued surfaces. The cracks are not really mechanical cracks but rather of optical size. Shiver may refer to the tendency of Plexiglas to optically separate along chains regardless of the cause, with gluing being only one cause.-- Gnarlodious 22:09, 22 January 2007 (UTC)

Any resources on the machining or working of perspex?

Is there any online information or even printed material on how this material is used, kind of a practical guide to designing and making things with perspex?

The vendors used to publish such materials (I have such a softcover-book from (I think) Rohm and Haas) and may still do so. If not, Google is always a good starting point. You won't go far wrong to think of the stuff as "soft metal that melts easily", that is, treat it like you'd treat aluminium (fine-pitch cutting tools, etc.) except minimize friction or the duration of the friction and you'll be close. Solvent welding (gluing) is an obvious difference, of course. :-) And, depending on the application, you may want to re-polish cut edges. Increasingly-fine grit sanding followed by buffing compounds should do the trick.

Atlant 5 July 2005 11:15 (UTC)

SMILES correct?

The SMILES string seems to display only the monomer, correct? Should it nevertheless remain in the table? Why is one of the C's in square brackets? AxelBoldt 23:51, 13 March 2006 (UTC)

Toxicity?

Could anyone describe the toxicity of polymethyl methacrylate in common modern environmental situations, for example: 1) consumption of water that has had contact with Plexiglas 2) consumption of water that has had contact with heated Plexiglas 3) at which temperatures does Plexiglas begin to off-gas toxic chemicals

In particular, i am trying to determine the usefulness of this material in making #REDIRECT solar cookers, which involves potential contact with food and high temperatures (200C). [End of unsigned comment.]

Acrylic melts easily. I wouldn't use it in a high-temperature environment.--Srleffler 22:35, 28 May 2006 (UTC)

The temperature that you are trying to use the Plexiglas at is too high and it will deform the material, however the residual monomer in the material will not be harmful. Consider that there are FDA approvals for Plexiglas, you can contact tech specialists at Arkema Inc/ Plexiglas Webpage. (EMILIOJPEDRAL (talk) 00:27, 9 July 2008 (UTC)) Emilio Pedral.

Company name

The article asserted that plexiglas was first brought to market in 1928 by "the German company Röhm". I think this is incorrect, and that the company that was meant here was actually Rohm and Haas. If so, the name was certainly incorrect, because (a) it omitted Haas, who was a company founder and whose name has always been in the name of the company, and (b) Rohm is not spelled with a dieresis. But my correction could be mistaken, if what was really meant was a German company named Röhm. -- Dominus 18:46, 30 March 2006 (UTC)

Note also that:

• The invention of the material itself is often attributed simply to "Röhm". Otto Röhm was the chemist. His partner, Otto Haas, was the business and sales guy.
• Otto Röhm's name is spelled with a dieresis, but the name of his company, Rohm and Haas, is not.

So if one wants to attribute the material to its inventor, one could say that it was invented by Röhm. But if one wants to attribute the material to the company, one could say that it was brought to market by Rohm and Haas.

See for example the official company history of Rohm and Haas. -- Dominus 18:53, 30 March 2006 (UTC)

Also note that Rohm and Hass in America is no longer manufacturer of Plexiglas and that these PMMA resins and sheets are currently produced by Arkema Inc. through it's Altuglas International Division. Plexiglas Webpage. (EMILIOJPEDRAL (talk) 00:22, 9 July 2008 (UTC))

Melting, forming at 100C?

I see two things that bother me about this entry. The first is in the properties table, where a melting point is listed, although PMMA is known to be amorphous - that is why it is also transparent. Only highly isotactic & syndiotactic PMMA will crystallize and therefore melt.

The second is the statement, that PMMA can be easily formed, by heating to 100C. Heating what to 100c? I assume the monomer, methyl methacrylate (MMA).

Matijac 20:06, 4 April 2006 (UTC)

I think formed in this context doesn't mean produced in a chemical reaction, but molded into a different shape. —Keenan Pepper 00:09, 5 April 2006 (UTC)

That cannot be the case, the glass transition is 105 degrees C. Glassy materials cannot be "formed" into shapes below their glass transition temperatures. If noone else has any suggestions, I will correct these two items.

Matijac 11:20, 14 April 2006 (UTC)

I also thought that that statement meant "created" as opposed to "molded". It is not clear. --Diom1982 16:28, 6 November 2006 (UTC)

I removed the text as at best it was ambiguous and at worst it was incorrect. I instead added a note that its typically processed at around 240-250 degrees celcius, according to MatWeb (see references). I will be adding other improvements to this article over the next few days. Next on my list of things to fix on this article include: arrange the properties by catagory (ie, optical properties, thermal properties, mechanical properties ect). After that I hope to add a section about the synthesis of PMMA and move any information related to synthesis to that section. CoolMike 17:30, 21 November 2006 (UTC)

Also In regards to the melting point issue at the top of this section: you are only half correct there. While it doesn't have the sudden transition from one state to another it does melt. Just as the Tg is defined as the inflection point on various property vs. temperature curves so too is the melting point defined as the midpoint of a range of values. Tg isn't a definant point in reality either, it can be considered a range, and the same material will have a different apparent Tg when the Tg is estimated by different means. I double checked the melting point data to be safe and it seems correct to me. CoolMike 17:17, 22 November 2006 (UTC)

I cannot find the reference for your melting point data.EDIT: OK, I found it on the MatWeb page. That is completely wrong, though. I don't have an issue with the range of melting point temperatures, but rather with the fact that PMMA does not crystallize and therefore does not melt. If what is meant is some sort of softening point, pertaining to mechanical properties, that's a different issue. But a melting point as a thermodynamic property is very well defined and PMMA simply doesn't have one. Unless of course it's isotactic or syndiotactic, none of which are mentioned and none of which are used in plexiglass.Matijac 20:27, 31 October 2007 (UTC)

Reference:http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1958/80/i07/f-pdf/f_ja01540a068.pdf?sessid=6006l3

I agree with Matijac. PMMA is an amorphous polymer and can not melt. It has a glass transition temperature around 105C where it softens but this is as Matijac points out not a melting temperature. Still, a melting temperature is stated in the properties box. This should be removed. A boiling temperature is also stated. A polymer will not boil, but decompose above a certain temperature.

--Tofteberg (talk) 13:19, 21 August 2009 (UTC)

Is plexiglass really shatter proof because from what I can tell it does shatter. I can show you links to news reports of people being sent to the hospital in a hockey game recently. 155.33.109.148 00:28, 12 December 2006 (UTC)

Plexiglass will shatter. Or at least, when it cracks, the end result is very similar. I had a single windowpane temporarily replaced with a piece of leftover plexiglass until I decide what to do about the entire window, which is in bad shape (that's the simple version of the story). Anyway, when he was cutting the glass to size parts of it splintered off. It wasn't quite the same effect as silica glass, but it still produced shards. Personally, I wouldn't recommend using plexiglass in a window. Non-plastic is the way to go. --Trakon 00:58, 26 February 2007 (UTC)

Sources?

There should be some sources cited for the large amount of material in this article... Valrith 21:52, 5 October 2006 (UTC)

I agree, I'm working on adding some scources. Will the person who wrote the information about the UV and IR absorption of PMMA please let me know where this information was found? I know it would take me hours to find a reliable scource for that sort of information. CoolMike 17:31, 21 November 2006 (UTC)

You can get much more information by downloading the PDF file related to the Physical Properties of Plexiglas Plexiglas PDF's (EMILIOJPEDRAL (talk) 00:32, 9 July 2008 (UTC)) Emilio Pedral.

Title of the article

I have never ever heard anyone refer to PMMA as acrylic glass. Some people will refer to it as Acrylic while most simply refer to it by the particular brand name of the polymer in use, or when talking about the resin in general its usually just called PMMA. Does anyone know of an industry that uses the term acrylic glass? I am a plastics engineer and I've not heard it refered to by this name before, but it may be a case of regional differences. I'd like to get some feedback before considering making a change to the title of the article. CoolMike 15:57, 21 November 2006 (UTC)

Where does it say plexiglass doesn't shatter?

Plexiglass shatters. It happens all the time in hockey rings in fact it happened just recently. 155.33.109.148 00:26, 12 December 2006 (UTC)

just to let you know, plexiglas actually doesnt shatter. It actually breaks, shattering is a multitude of broken pieces scattered throughout the entire pane —The preceding unsigned comment was added by 209.191.208.155 (talk • contribs) 03:14, 12 December 2006 (UTC).

User 209.191.208.155 is incorrect. I've personally seen acrylic (Plexiglas) shatter during machining operations. If the impact is sharp enough, it will shatter, though not in the way glass does. —Quicksilver^{T @} 17:35, 3 January 2007 (UTC)

I'm not aware of any material that can't be shattered under the right loading/temperature conditions, PMMA included. Saying something is "shatter proof" is usually an over simplification and is outright wrong. However, saying something like "under typical use, PMMA does not normally shatter". For sources that either talk about or show plexiglass shattering, see except from book and video. Also, PMMA becomes exceedingly brittle when the temperature is reduced and will shatter when cooled by dry ice or liquid nitrogen and struck with a hammer or against an object (as will most common materials). Also, I'm changing the line to say something along those lines.SmoJoe (talk) 17:48, 25 June 2008 (UTC)

Tg and young's modulus

I added the Tg and Young's modulus. These came from Introduction to Physical Polymer Science. L. H. Sperling, 3rd ed., Wiley-Interscience, New York 2001. I don't know how to cite these in the infobox. If you feel that this citation is important, please feel free to cite it. User:carsonc 16:04, 14 December 2006 (UTC)

Added information about acrylic watch crystals and contact lenses.

I'm a moderator on a watch collector's forum, and discussion about acrylic watch crystals comes up all the time. I've added a new paragraph to the "uses" section.

Also, as my wife is studying to be an optometrist, she pointed out that hard contact lenses are no longer made with acrylic, so she edited that section as well. —The preceding unsigned comment was added by 69.203.82.86 (talk) 02:04, 12 May 2007 (UTC).

UV-proofness

I can not find information about UV-proofness of PMMA. Does anybody have data about capability to stand UV radiation and how is it to compare with PC and PS? Tiit tiitk@msn.com —Preceding unsigned comment added by 62.65.35.22 (talk) 08:16, July 17, 2007

Cast vs. Extruded?

I came here today to study the differences between cast vs. extruded acrylic. I created a project out of scrap pieces from the shop where I work (I'm in a different department so I'm not 100% familiar) only to discover that I've used two different types of acrylic and they have very different characteristics. Yet the only reference I can find in this article is that the extruded form is used in pressurized aircraft. Nothing else seems to be mentioned on the subject. Compare this with the vast array of information about how different types of glass is manufactured. —Preceding unsigned comment added by 75.162.104.28 (talk) 18:40, August 1, 2007

Mempile's Teradisc

If someone would be so kind as to add this new interesting product to the Other Uses. A proposed terabyte capacity optical media disc. Currently stores between 600 to 800 gigabytes. [1]Axion22 16:17, 23 August 2007 (UTC)

Properties

At the end of the Properties section:

"To produce 1 kg of PMMA, about 2 kg of petroleum is needed. In the presence of oxygen, PMMA ignites at 460° C and burns completely to form only carbon dioxide and water."

Does "in the presence of oxygen" mean in air? Or does it have to be a pure oxygen atmosphere, otherwise there are other products? This point is unclear from the sentence as it stands.

WikiReaderer 14:28, 30 September 2007 (UTC)

It's moved to the lead now. I have added a clarifyme tag to attract anyone who might know. The claim needs to further qualify under what conditions this occurs, pressure as well as temperature and percentage of oxygen. -Wikianon (talk) 18:56, 24 February 2008 (UTC)

Well first of all, temperature is given, 460 °C, and how about we go with atmospheric pressure...it just makes sense, and enough oxygen to complete the combustion reaction? The might be just any oxygen at all, but why is this even a big deal? 24.164.75.68 (talk) 21:04, 10 June 2008 (UTC)

I agree that it is not an important point to make. While we're at it, why not include relative humility, wet-bulb temperature, etc etc. It is clear enough as it stands because it simply implies that combustion needs to take place in the presence of oxygen.AnimeEd (talk) 04:38, 17 June 2008 (UTC)

I disagree on the "only" carbon dioxide and water: it depends on the factor we have seen here and more. —Preceding unsigned comment added by Bonarda (talk • contribs) 21:01, 12 November 2008 (UTC)

Redirects needed

Poly(methyl methacrylate) (with the parenthesis) is bolded in the article, but gives a red link. As does Limacryl, R-Cast, Plazcryl, Acrylex, Altuglas, and Polycast. Acrylic is bolded, but actually directs to a disambiguation page. -- 128.104.112.85 (talk) 20:36, 8 April 2008 (UTC)

Temperature Qualities?

This does not really have to do with the article but I want to ask a question of the experts. I did some research on the Internet but with only limited answers. I have just installed two 2' x 4' pieces of plexiglas on top of a container that I want to get hot. It will be a solar water heater. It must have got hot because I noticed that the plexiglas has shrunk a bit. There is now about a 1/8th inch gap between the two pieces. According to various sites it begins to shrink at about 180 degrees F. My question is will it continue to shrink or after a period of time can I expect that it has finished shrinking and I can bring the two pieces together again and fasten them down and join them together? Conversely, will it expand or break when it gets cold out (it can get to about 10 degrees F here in the winter)? Thank You. 4.246.200.226 (talk) 02:28, 4 August 2008 (UTC)

'Plexiglas' as a common name for acrylic glass

I added 'Plexiglas' as a common name for acrylic glass because this is how we named this product the most commonly here in Europe. I didn't know until I read the article it was a trademark name ! Lvr (talk) 11:21, 5 December 2008 (UTC)

Title should be Poly(methyl methacrylate)

I like the article and enjoy all the effort everyone's put into it. However, it seems to be a combination of two articles that need to be split. There is some good generic information on acrylic glasses in the article, but by far the majority of the article focuses on one specific example: poly(methyl methacrylate). Acrylic glass is such a generic term for PMMA, it is similar to putting the Wikipedia entry for Tiger under the title Feline. PMMA needs its own article, and the terms PMMA and poly(methyl methacrylate) should not redirect here. I propose moving this article ASAP, so I'm posting this here for some discussion time before any move. Thoughts? Hokiesvt (talk) 19:16, 26 March 2009 (UTC)

Since no one's replied, I'm removing this from WP:RM, and you can do what you like with the article. I would suggest, based on your comment above, that the ideal outcome would not be a move, but a split: that is, cut out the material here that is specific to Poly(methyl methacrylate), move it to that article, and then keep a summary here: Acrylic glass would then stay here (unmoved) as an article on the more general topic. However, that is just a suggestion; I leave the rest up to your editorial discretion.--Aervanath (talk) 15:56, 1 April 2009 (UTC)

I totally agree with your proposal to split the article. There is a lot of material that is specific to only to PMMA or plexi. As such the scope of the article is rather wide and can lead to confusion. If there is not enough material to have a PMMA article, perhaps it could be widened to include all acrylic plastics. Iepeulas (talk) 19:34, 5 May 2009 (UTC)

Page moved to Poly (methyl methacrylate). Let the clean up begin! Iepeulas (talk) 23:14, 2 June 2009 (UTC)

Vacuum Forming PMMA?

Simple question, can it be done? multiple somewhat confusing statements above in the "...100c" discussion. I'm starting a project to make visors and face shields for a set of movie props and found a product that is "semi-transparent film of aluminum deposited on an acrylic substrate" Thus the question: Can it be vacuum formed? Nullexe (talk) 21:58, 18 November 2009 (UTC)

Hi, the talk page is for discussion the article not your project. The place for that is the reference desk. Wizard191 (talk) 22:44, 18 November 2009 (UTC)

I understand that. I was using the project as a frame of reference for clarifying my question about the properties of acrylic. I should have phrased my question better. Here's try two:

"Can PMMA be heated to a point where it will become malleable and useful for vacuum-forming applications, without losing cohesion completely or separating into other compounds?" Nullexe (talk) 22:54, 18 November 2009 (UTC)