Talk:Poly(methyl methacrylate)

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Health concerns?[edit]

Some people have health concerns about various plastics. They talk about psuedo-hormones. Does acrylic have any health concerns? Alternatively, can one reference someone claiming they are safe? For example, here is an article implying acrylic is safer than other plastics with bisphenol A.—Preceding unsigned comment added by Dfrankow (talkcontribs) 22:24, 27 December 2009 (UTC)

Seconded. If this stuff is being used to repair people's eyes and stuff there have got to be some safety-data available somewhere. Let's see what we can find, people. Koyae (talk) 06:39, 10 January 2010 (UTC)

Incorrect data?[edit]

  • "Melting point : above 160 °C
  • "Thermoplastic PMMA is typically processed at 240–250 °C"

This seems extremely unlikely, assuming that processing refers to molding, extruding etc. I can't imagine how one might extrude a gas. Surely the processing temperature is in degrees Fahrenheit, not Celsius (i.e. around 125-130 °C )? I have no data, this is only an inference of a typo, so will not edit. 92.24.188.91 (talk) 01:33, 30 January 2010 (UTC)

I've corrected the melting point and replaced the processing temperature with the glass transition temperature range. As for the boiling point, I just added a {{cn}} tag. Wizard191 (talk) 02:21, 1 February 2010 (UTC)

Poly(methyl methacrylate) is an amorphous solid, and does not have a melting point. It has a glass transition 105-120 °C, which depends on the synthesis method. Below the glass transition temperature it is a hard clear solid, and above it PMMA is a viscoelastic liquid. Using "melting point" to describe the softening of PMMA is incorrect because "melting point" is a specific type of thermodynamic transition that is not present in PMMA. Perhaps who ever put this in meant the "working temperature" because PMMA could be molded or extruded above its glass transition temperature.146.6.118.231 (talk) 22:21, 4 December 2012 (UTC)

Trade names[edit]

Hey you two, play nice. While I think Wizard191 has a valid concern in that the list of trade names is somewhat unwieldy and could use better sourcing, I'd tend to agree with Bachcell that simply mass deleting it isn't the right solution, and certainly adding ~15 {{fact}} tags to one sentence is WP:POINT-making and does not improve the encyclopedia. —DragonHawk (talk|hist) 22:58, 13 July 2010 (UTC)

What if everyone in my village calls it plastik or plex? There are dozens of names for some of them, especially PMMA, which doesn't mean we should clutter the lead with 15 bolded items. I think Wizard191 was avoiding an edit war, but I would support deleting all unreferenced names for now, and if they all end up to be notable, they should be moved to a separated section. Materialscientist (talk) 23:18, 13 July 2010 (UTC)
Again, adding ~15 {{fact}} tags to a single sentence does not improve the encyclopedia. It makes the lead almost completely unreadable. That's WP:POINT-making, pure and simple. I completely agree that the long list of names doesn't belong in the lead section, but the solution to that is not "delete them" but instead "move them out of the lead section". It prolly took less effort to do that just now then it did to add those fact tags. There's an added bonus in that that section can now be tagged {{refimprove}} without making it entirely unreadable. I did some quick Google work and threw in a few references while I was at it. Please seek consensus solutions. The encyclopedia will be the better for it. —DragonHawk (talk|hist) 23:45, 13 July 2010 (UTC)
Thanks. Materialscientist (talk) 23:49, 13 July 2010 (UTC)
DragonHawk, what do you want me to do? Leaving the names as is is unacceptable to me for the reasons I will give in a second. I tried deleting them, but you guys don't want me to; that's fine. So I did the only other thing, which is adding {{cn}} notes, however that still doesn't cut the stuff. What gives? I don't feel that the weight is on me to find refs for unreferenced advertising.
As for my reasoning with the trade names, it's very easy to find references that state what some company calls their brand of "fill in the blank for your type of plastic resin". However, this is really just advertising. The only time that a trade name should be included is if the name is widely used in place of the polymer name; for instance (these are at least true for Chicago, IL): vespel, delrin, syrofoam, and mylar. I understand that in other countries there are other brand names that are common, but all of these need refs to support this. A good example of this in a non-polymer article is easy out. Wizard191 (talk) 23:51, 13 July 2010 (UTC)
Wizard191: What I want you to do is follow the Wikipedia:Dispute resolution process. You deleted a bunch of names, someone objected. In response, you took a bad lead section and made it much worse. Hence WP:POINT. • As a productive alternative, you could have hopped over here to this talk page and explained your concerns. and tried to reach an agreement. Or you could have done what I did, and moved the name list to a new section with a quick cut-and-paste. That took me all of 20 seconds. I did a bit more after that, but you could have done just the cut-and-paste and made good progress. • I agree that listing every possible brand name would be neither practical nor beneficial to the encyclopedia. However, documenting well-known brand names is of benefit to readers. Someone has attempted to do so. Deleting it without even trying to verify it is not constructive. I've picked a few entries, Googled them, and found supporting references very easily. Removing questionable material is one thing, but just doing a mass-delete without even trying to verify is another thing entirely. Verifiability is required. Citing sources is a strong recommendation, but should also be balanced with a constructive attitude. —DragonHawk (talk|hist) 00:10, 14 July 2010 (UTC)
Getting practical, I would leave those names which made it to Britannica/Webster and alike and delete others, unless reliable secondary sources come out (yes, google and company sites are not such sources). Materialscientist (talk) 00:15, 14 July 2010 (UTC)
Materialscientist, I completely agree. Wizard191 (talk) 01:55, 14 July 2010 (UTC)
Okay, some more verification work has pruned the list down significantly. Altuglas definitely appears to be notable. The mfg site claims 25% of world production. There's an obvious conflict-of-interest there, so we should track down a reliable, independent source for verification purposes, but it's not evil to reference a notable manufacture's own claims even once we find independent sourcing. Same story with Optix (mfg Plaskolite) -- lots of Google hits (Optix+acrylic=345K), mfg claims to be the largest, but wants better sourcing. —DragonHawk (talk|hist) 13:40, 14 July 2010 (UTC)
DragonHawk, I disagree with your premise for inclusion, which seems to be google hits/market share. Like I said above, I only think inclusions should be if the trade name is widely and commonly used in certain countries/fields instead of the polymer name. Wizard191 (talk) 14:15, 14 July 2010 (UTC)
If a company's production makes up a major part of the market, that is worth mention. Note that I'm not asserting "significant market share == people use the brand name as a generic term in every-day speech". Perhaps the presentation in the article should be improved to make that clearer. But documenting major producers is an important part of any article. We shouldn't have an article on soda-pop without mentioned Coke or Pepsi; we shouldn't have an article on fast food without mentioned McDonald's. And I'm not using Google hits as proof of anything, merely as a way to check a claim. If a company claimed to be the biggest producer but nobody had ever heard of them, that would be highly suspicious; that does not appear to be the case with Plaskolite. —DragonHawk (talk|hist) 16:30, 14 July 2010 (UTC)
Fair enough, as long as non-primary reliable sources can be found. Wizard191 (talk) 17:56, 14 July 2010 (UTC)

Colored PMMA image[edit]

This image was added and then removed. (Provided a description is added) is it useful for the article? Materialscientist (talk) 03:26, 2 August 2010 (UTC)

I think the article should have something along those lines -- simple sheets, to illustrate the basic material. That image in particular isn't ideal for what I'm thinking of, though. It's got a specific brand name, and I'd prefer something that shows opacity better. Something like this or this or this (but Free Content, of course). Until something is contributed... that's better than nothing, I suppose. We could easily trim out the logos, except that file doesn't have license/permission information. I've added a request for info on that to the uploader's talk page. —DragonHawk (talk|hist) 22:21, 2 August 2010 (UTC)

Properties[edit]

A poster to this thread claims that roughed-up PMMA is will scintillate with ionizing radiation:

As for scintillation plastics, just frost the surface of plexiglass with some sandpaper, it works great!

True or false? I'm rather doubtful, but if true, it should be included in the article. JKeck (talk) 02:41, 15 August 2010 (UTC)

Now there's a dab page for PMMA[edit]

The template now falsely claims that "PMMA" directs to this article. In fact, it should (and once did), but does no more. It directs instead to the DAB page, where there are three items, each of which is far less well known than the plastic. One or the other thing has to go: this template has to be fixed, or the redirect has to be fixed. I can't figure out how to do either one. I would PREFER that the default redirect be changed to here (this article) rather than the dab, and that's it. The present template on this article now would then be left alone since it would THEN be correct. Thanks to anybody who can do the deed, or something that is at least consistent (if you dont want this the primary redirect from PMMA, then can you figure out what template we want?). SBHarris 04:46, 2 December 2010 (UTC)

Now that PMMA no longer redirects here, this article doesn't need a disambig template hatnote anymore. A link to or search for PMMA will get the reader to the dab page; the reader will then click through to here. A link to or search for Poly(methyl methacrylate), on the other hand, obviously wants this article. See WP:NAMB for the full treatment. • As far as whether PMMA should be disambiguation page or a redirect here, that's best discussed on the talk page there. Me, I don't have an opinion.  :) You can consult WP:PRIMARYTOPIC for the relevant style guideline, and WP:RM for the move procedure. If you want to do it, create a new talk section at Talk:PMMA and use the {{move}} template, e.g.:
{{subst:move|PMMA (disambiguation)}} Explanation of your rationale. ~~~~
Hope this helps! —DragonHawk (talk|hist) 13:22, 2 December 2010 (UTC)

Other uses[edit]

The sentance "Smooth PMMA surface can be easily nanostructured by treatment in oxygen radio-frequency plasma[34] and nanostructured PMMA surface can be easily smoothed by vacuum ultraviolet (VUV) irradiation.[34]" can be deleted in my opinion. It is common to use it in e-beam lithography and that is an important fact, but the nanostructuration by oxygen-plasma is just a side effect, wich is not common use, or to be more precise: It is common use to clean samples from PMMA by burning the PMMA away with this plasma, if the PMMA is to much crosslinked to be dissolved in Aceton. See: http://iopscience.iop.org/0268-1242/11/8/021 I think that use of PMMA could be much more intersting to be mentioned in the article.--Do ut des (talk) 21:49, 14 March 2011 (UTC)

The history of PMMA is incomplete. William Chalmers, who is credited with discovering plexiglas at McGill Univesity, is not mentioned. He should be mentioned as well as his specific contribution. — Preceding unsigned comment added by 8.24.1.220 (talk) 13:52, 18 March 2013 (UTC)

Optical properties[edit]

"PMMA passes infrared light of up to 2800 nm and blocks IR of longer wavelengths up to 25000 nm. Colored PMMA varieties allow specific IR wavelengths to pass while blocking visible light (for remote control or heat sensor applications, for example)." There is no source for transmission in IR. Shalom25 (talk) 09:44, 20 March 2013 (UTC)

The source for this information is here, on page 7 right column "Infrared Transmittance". However I feel this phrase could be rephrased for better clarity.
Gromain47 (talk) 15:42, 11 June 2014 (UTC)

History: polymerization process that turns methyl methacrylate into polymethyl methacrylate[edit]

In section "History" the english article says "The German chemists Wilhelm Rudolph Fittig and _____ Paul discovered in 1877 the polymerization process that turns methyl methacrylate into polymethyl methacrylate." de:Rudolph Fittig#Wissenschaftliches_Werk says that Fittig discovered Methacrylic acid (and gives a source of 1880) and that G. Kahlbaum made PMMA (Plexiglas) from it. Are there any source about who discovered the polymerisation into PMMA? --Wilhelm-Conrad (talk) 22:40, 8 April 2013 (UTC)

Uses[edit]

A major consideration when using PMMA cement is the effect of stress shielding. Since PMMA has a Young's modulus between 1.8 and 3.1 GPa,[31] which is greater than that of natural bone (around 14 GPa for human cortical bone),[32] the stresses are loaded into the cement and so the bone no longer receives the mechanical signals to continue bone remodeling and so resorption will occur

The moduli given do not support stress shielding. 3.1GPa is less stiff than 14GPa. — Preceding unsigned comment added by 65.216.152.2 (talk) 19:25, 6 November 2013 (UTC)

Who is "_______Paul"??[edit]

I can find no evidence for the real first name for the "Paul" fellow who is being cited here as one of the co-discoverers of the 1877 process for making PMMA. And it's kinda weird: Fittig is mentioned repeatedly in searches, and sometimes exclusively, but "Paul" is mentioned only occasionally and never with any kind of first name (this includes searches in paper-printed and published books, the kind of place where you'd expect someone to have done their homework). It almost stinks of a conspiracy of some sort, or of a bad, bad case of parroting of misinformation that goes back to at least 1956 with William John Roff's book "Fibres, plastics, and rubbers: a handbook of common polymers". Since then the mysterious "Paul" has been mentioned-- by last name only-- by Joe Schwartz, Kyung-Sun Lim, Charlotte and Peter Fiell, and Elizabeth Bogle, among others-- these are all big names on the field of plastics and acrylics (though not, apparently, of history or of fact-checking the details). I propose that unless someone can come up with a first name for him, that ______ Paul be removed from this article. KDS4444Talk 04:02, 3 March 2014 (UTC)

I also searched on the internet for this mysterious Paul person and I too can not find anything. I suppose that until a credible source can be cited we should probably remove the mention of him on the article. Qasaur (talk) 13:12, 14 May 2014 (UTC)