Talk:Polycarbonate/Archive 1

Untitled
I have seen a polycarbonate ipod nano case and need to know how hard it will be. Is it knock resistant?

Most widely used polycarbonate
An anonymous editor just eliminated the following text:

The most widely used industrial polycarbonate is bisphenol A, and sometimes the general term &ldquo;polycarbonate&rdquo; is used synonymously with this particular chemical.

Now I don't know enough about polycarbonates to say whether or not this is a true statement, but I always get worried when someone comes along and makes a change like this without even leaving us a comment in the audit trail.

Does anyone know whether this statement was true (and should terefore be reverted back into the article)?

Atlant 19:33, 10 Feb 2005 (UTC)

it is true. Bisphenol-A Polycarbonate is most used.


 * It is not true. Bisphenol A is a specific phenol, and is not a polymer, but polycarbonate is a polymer. Bisphenol A is used to make the most common polycarbonate, but it itself is not a polycarbonate. Polonium 19:29, 5 March 2006 (UTC)


 * That is corrent, bisphenol A is a specific molecule and is the most common monomer used in the sythesis of polycarbonates. Also, the very first line of this entry says that polycarbonates are "thermoplastic polyesters". This is by definition not true. A carbonate is a carbon bonded to three oxygens, an ester is a carbon bonded to two oxygens and another carbon. Sorry I don't have time to create an account or correct the page, but I do have a PhD in organic chemistry and I am right - feel free to look it up... Head over to chemfinder.com and type in "Bis Phenol A" you'll even get the CAS number. —The preceding unsigned comment was added by 128.103.93.213 (talk • contribs).

Methanol considered harmful?
I was just reading this when i noticed Methanol down in the list of things that will damage polycarb. - Now im not a plastics expert, but i race RC cars, which have polycarb bodys, and burn 'nitro fuel' which is methnol based (often af much as 70/80%) And ive never know it to cause any problems at all.

Daniel


 * I agree, the list seems over cautious and I was surprised by some of the entries, but it is from a polycarbonate supplier's data sheet, so unless you can find a more robust source I suggest you just move it into the 'requires caution' list. njh 23:46, 31 December 2005 (UTC)

Addition
boys and girls, I copied some sentenses directly from my PhD dealing with the catalysis of poly(aliphatic carbonate)s taking as origins carbon dioxide and cyclohexene oxide, bit owing to lack of time (as well as my unknowledge) any figures explaining the chemistry of the reaction are provided. Sorry;D —The preceding unsigned comment was added by 85.28.103.235 (talk • contribs).

Problem with polycarbonate product
The product is body of led lamp for bathtub. Problem is that somehow water will get inside to the lamp.But not in every lamp, just some of them. Only way water can go in to the lamp is through the wall.In these cases it can be seen small flaws. Could it happend because of some cleaning chemicals? Or maybe we use wrong silicone for glueing? Should I change material? What materjal would be best if the temperatur inside the lamp is ca.70-75° C. And the materjal should have good transparency.

If somebody could help me I would be very grateful.
 * This is not an advice forum --Mr. Brown (talk) 00:59, 19 February 2008 (UTC)

Recycling
Is PC recyclable? What are the processes used? This is useful as many people search this articles (about plastics) are consumers who noticed some product fabricated with it.


 * It is recyclable (as with most thermoplastics, grind and remelt) but at least in the United States, it isn't commonly recycled :-(.


 * Atlant 15:23, 15 January 2007 (UTC)

I came to the page to find the recycling number and and code (e.g. #5 PP, or #4 LDPE) for polycarbonate. Can someone provide that? 128.135.131.100 (talk) 20:28, 16 April 2008 (UTC)
 * See Resin identification code - it's #7 OTHER - I've seen "PC" used for the code. --Random832 (contribs) 17:36, 12 May 2008 (UTC)

References?
I've deleted the following from the top of the page as I'm not sure why they're there. I guess they are (or were) references, and should thus be integrated into the text. -- hibou 22:17, 23 February 2007 (UTC)


 * A.K. vam der Vegt & L.E. Govaert, Polymeren, van keten tot kunststof, ISBN 90-407-2388-5
 * Marchant RE, Wang I (1994). Physical and chemical aspects of biomaterials used in humans. in ISBN 0-8493-4432-8

Interaction with salt
In the chart on interactions with other chemicals, ammonium chloride and calcium chloride are mentioned, but... how about sodium chloride... or sodium bicarbonate? Thanks. — Epastore 18:59, 1 April 2007 (UTC)


 * I don't have an authoritative source, but I expect that they are safe. I've used concentrated NaCl solution on PC with no visible sign of damage. --njh 04:29, 2 April 2007 (UTC)
 * "Using sodium hypochlorite (bleach) and other alkali cleaners on polycarbonate is not recommended as they cause the release of bisphenol A, a known endocrine disrupter." conflicts somewhat with http://www.nalgene-outdoor.com/technical/cleaning/index.html, which suggests baking soda (i.e. sodium bicarbonate, which is both a base and a buffer) be used for cleaning. --76.21.22.240 (talk) 02:46, 4 January 2008 (UTC)

Food Safety Issues
There has been a lot of talk about food safety issues and Polycarbonate. I noticed on the main article a study that suggests that industry funded studies tend to show that there is no safety concern, but government studies show that there is a significant safety concern. I have actually been looking into this, and I believe that this is completely false. The European Food Safety Authority, The Food and Drug, the Centers for Disease Control and Prevention and many other government organizations have declared that there is no perceptible risk to humans from polycarbonate contact with food or drink.

http://www.efsa.europa.eu/en/science/afc/afc_opinions/bisphenol_a.html http://unit.aist.go.jp/crm/mainmenu/e_1-10.html —Preceding unsigned comment added by 216.123.208.30 (talk) 20:46, 14 January 2008 (UTC)

Cleaned up and removed duplication
I removed the following from the Chemistry section because all of this data is duplicated in the "Properties" table:

Polycarbonate has : *a density of 1.20 g/cm3 *a use range from −100 °C to +135 °C *a melting point around 250 °C *a refractive index equal to 1.585 ± 0.001 *a light transmission index equal to 90% ± 1% *poor weathering in an ultraviolet (UV) light environment

Also removed redundant application information from the Synthesis section and made minor edits to the Application section. I also propose deleting the ambiguous "Properties" list that appears at the end of the Synthesis section. Please let me know if you think anything on there is critical, otherwise I will delete the next time I come around. Oanjao 22:14, 16 April 2007 (UTC)
 * Agree that that "properties" listing was unneeded. Removed it.  Thanks for pointing it out. ChemGardener 00:37, 17 April 2007 (UTC)

how strong is a polycarbonate plastic or glass?
I bought a polycarbonate sunglasses and I am into playing airsoft. I am just wondering if the polycarbonate lens of the sunglasses I bought can withstand an impact of a Ballistic Bullet(BB) with a velocity of 500 feet per second? thanks. —The preceding unsigned comment was added by Junpx (talk • contribs). A BB from unexpensive air gun can pass through an empty beer can (made of about 0.4mm Duralumin), if it hits it at right angle; probably these lens have similar impact resistance, unless they are significantly more thick. JerzyTarasiuk (talk) —Preceding comment was added at 17:56, 5 March 2008 (UTC)

what are 'domelights'? are they the same as skylights?
In 'Applications' (almost in half): "Building: domelights, flat or curved glazing, sound walls" - I could not find the word domelight both in Wikipedia (except here and in 'Blue_Sky_Mind') and in two paper dictionaries... JerzyTarasiuk (talk)

History / Discovery
Was Polycarbonate found in a lab or in someones kitchen? Who discovered it? How did they report it. how did they make it? Are there better methods now or do we use similar methods?

Also, Is there an easy way to make polycarbonate without a lab or specialised chemicals, or just with a simple set of chemicals. The reason I would request this is that a teacher or student may want to incorporate plastics into their science curriculum/studies, and run some simple experiment for understanding of the process/plastic/viscosity/sheering/non-newtonian liquid motion. —Preceding unsigned comment added by 60.234.214.1 (talk) 21:34, 16 May 2008 (UTC)

Mistake in balancing...
The equation for the deprotonation of bisphenol A is missing a water molecule on the product side... —Preceding unsigned comment added by 68.227.164.192 (talk) 19:52, 11 July 2008 (UTC)

More bisphenol A studies
ScienceDaily.com - Toxic Plastics: Bisphenol A Linked To Metabolic Syndrome In Human Tissue Original reporting: Univ. Cincinnati Mentions "They report their findings in the Aug. 14, 2008, online edition of the journal Environmental Health Perspectives." PDF of report:
 * Shenme (talk) 16:03, 5 September 2008 (UTC)


 * Is this article overstating the risks of bisphenol A? According to http://www.bisphenol-a.org/human/polyplastics.html :
 * "the estimated dietary intake of BPA from polycarbonate is less than 0.0000125 milligrams per kilogram body weight per day. This level is more than 4000 times lower than the maximum acceptable or "reference" dose for BPA of 0.05 milligrams per kilogram body weight per day established by the U.S. Environmental Protection Agency.
 * Stated another way, an average adult consumer would have to ingest more than 600 kilograms (about 1,300 pounds) of food and beverages in contact with polycarbonate every day for an entire lifetime to exceed the level of BPA that the U.S. Environmental Protection Agency has set as safe.
 * The European Commission's Scientific Committee on Food (SCF) has also recently confirmed the safety of polycarbonate plastic products for contact with foods and beverages. The SCF estimated total dietary intake of BPA from all food contact sources, including polycarbonate plastic products and epoxy resin coatings, to be in the range of 0.00048 to 0.0016 milligrams per kilogram body weight per day, which is below the Tolerable Daily Intake set by the SCF of 0.01 milligrams per kilogram body weight per day.".
 * It does not sound as dangerous as the Wikipedia article suggests? 78.105.234.140 (talk) 01:52, 12 January 2009 (UTC)

When was polycarbonate invented?
When was polycarbonate invented? Anthony Appleyard (talk) 05:11, 12 October 2008 (UTC)

Assessment comment
Substituted at 15:35, 1 May 2016 (UTC)