Talk:Polylactic acid

Untitled

Does the mention of the substance's use by a cigarette company: "Philip Morris's iQOS heets include PLA to slow the vapour down without absorbing it, giving it time to cool to a more pleasant temperature before inhaling it" constitute advertising? The use of the brand name and the language "more pleasant" seems non-neutral in tone. Antifracture (talk) 14:23, 21 August 2019 (UTC)

Can sugarcane bagasse be used as a substrate in citric acid production by Aspergillus niger ?

1st Section

The name "polylactic acid" does not follow any naming convention, but is not ambiguous.

Poly lactic acid is not an IUPAC name because "lactic acid" is not a IUPAC name. Much like poly ethylene (not an IUPAC name) and other polymers, the polymer is named after the starting monomer, not the resulting polymer (poly ethylene is a straight chain with no double bonds, whereas ethylene is C2H4 [has a double bond]).

"and potentially leading to ambiguity (PLA is not a polyacid (polyelectrolyte), but rather a polyester)"

The chemical structure illustration should have a straght line where the squiggly line is, because it is a just a methyl group for polylactide.

Discuss... — Preceding unsigned comment added by 72.37.244.76 (talk) 22:59, 7 July 2011 (UTC)

There is something lacking the the claim that it is difficult to recycle PLA. Later sections in the page include Loopla as a company capable of recycling PLA through the fairly simple thermoprocessing. Can the issue of recycling be broken up into technical feasibility (not that difficult) and practical feasibility (collection is basically a non starter, problems with contaminating recycling, studies on practicality. --Smrf (talk) 00:22, 20 July 2011 (UTC)

Can, possibly. Just do it (see why)! q:) Vinne2 (talk) 17:53, 20 July 2011 (UTC)

CAS Number is 9051-89-2. Please check!

Lactide is not a monomer

... but strictly a dimer! — Preceding unsigned comment added by 150.227.15.253 (talk) 09:35, 31 January 2014 (UTC)

Production

The graphic shows condensation reactions but I think the Stoichiometry is not accurate. The dimer formation produces two water molecules, so shouldn't the right arrow show "-2 H2O" instead of only "-H2O"? — Preceding unsigned comment added by 190.247.64.79 (talk) 17:30, 22 July 2013 (UTC)

Now that you point it out, I wonder the same thing about the Stoichiometry, although I don't really know how to edit the image where the reaction is displayed. Tacitly (talk) 23:19, 23 April 2016 (UTC)

Merging

• I decided to merge the info contained in article polylactide into polylactic acid as suggested. Both articles dealed with the same subject. I believe all relevant information of both articles has been inclueded and there should be no duplicate info.

Berserker79 12:55, 31 August 2005 (UTC)

17/10/05: Fixed Classmates Vandalism.

Comment -

Where does the idea come from that PLA is a sustainable (renewable) plastic material, as opposed to petroleum-based plastics. This claim ignores the huge amounts of petroleum required for the agricultural production of the feedstocks for PLA. See quote below from article.

--Your point is well-taken, production of PLA currently requires energy (electricity for reactors, fossil fuel for transportation of corn). On the other hand, unlike crude oil derived materials like PE, PP, PS, PVC, etc, PLA material is sourced from a renewable source (i.e. plant). It is also eventually possible to sustainably source electricity (via wind power, solar thermal, etc). And transportation might be possible via electric vehicle. So from a purist standpoint, PLA as produced today is not 100% sustainable. But then, what plastic material is today? PLA probably comes closest to 'sustainable' currently, and can be 100% sustainable in the future.Mill haru (talk) 16:03, 12 September 2010 (UTC)

"The degree to which the price will fall, and the degree to which PLA will be able to compete with NON-SUSTAINABLE petroleum-derived polymers, is uncertain".

PLA can be derived from sources such as the unused parts (that would normally be thrown out, I might add) of the sugar cane, and other carbohydrate-rich crops. Other ways of agricultural production are being researched to exclude fossil fuels, I'm quite sure. If you're going to go by that reasoning, then there is really no point in the word 'sustainable' as every aspect of our lives currently revolves around fossil fuels, which are not renewable. ~Deadly-Bagel (talk)

Comment: Using "sustainable" here might not make any sense. Perhaps "less environmental damaging", or "an environmental better solution", but using "sustainable" can be misleading. Especially, if it depends on a use of non-fossil (renewable) energy source in the production and transportation, which is not the case always. Then it can actually be very far away from being "sustainable".--Duckislate (talk) 23:50, 9 February 2011 (UTC)

Biodegradable stents

A stent is a wire mesh tube that is used to open up arteries. Abbott Laboratories has developed a bioabsorbable stent made of polylactic acid. Since I work for Abbott I would rather someone else make the entry. Otherwise I may add it at a later time. Scot.parker 13:49, 26 October 2006 (UTC)

Durable Applications

"The physical blend of PDLA and PLLA can be used to widen the application window and include applications such as woven shirts (ironability), microwavable trays, hot-fill applications and even engineering plastics (in this case the stereocomplex is blended with rubber-like polymer such as ABS)"

I'm rather skeptical about use of any variety of polylactide for a number of those things, because of the degradation in the presence of moisture and/or bacteria, both of which are likely to be present. The PURAC site doesn't make any mention of it, so sourcing it might be nice. I know about the medical applications and the disposable goods (packaging, compost bags, plastic cutlery, etc) and can provide a source for those if needed. But I haven't seen anything on "woven shirts" for example, or in non-biomedical engineering plastics. Gjc8 12:50, 18 February 2007 (UTC)

I am curious about this too. I heard about polylactic acid while reading about the RepRap project, where they are trying to use it because it is environmentally friendly and can be produced from vegetables, which should be possible for communities in the developing world. But manufactured items that start biodegrading the minute they come out of the fabber might not be very useful, or at least not useful for a long time. -- WillWare (talk) 00:07, 25 February 2008 (UTC)

New article?

I notice the "see also" section at the bottom for biodegradable polymers. Is the topic of biodegradable polymers worthy of an article of it's own, or possibly a new section within polymers? The list is beneficial information, but just grouping them here seems ungood. Verdatum 21:57, 6 June 2007 (UTC)

I also think it's a good idea, but I lack the expertise to do anything more complicated than copy this list to a "list of biodegradable polymers" page. Anyone else want to step up? :) Indeterminate 09:16, 25 July 2007 (UTC)

What i advise as a solution is a category of list of biodegradable polymers or a article list of biodegradable polymers — Preceding unsigned comment added by SirSharp (talk • contribs) 19:26, 22 October 2022 (UTC)

Cracking

I'm not a chemist - I have no idea what this is. I added a link from "cracking plants" to Cracking (Chemistry), but that's just a guess from reading both pages. Is the oligomer -> dimer process what's being referred to as "cracking"? Indeterminate 09:16, 25 July 2007 (UTC)

Cracking means exactly that - cracking the molecule into separate pieces. This is mainly used on polymers to obtain monomers or polymers of shorter length. Oligomer, I'm not quite so sure of. I think it's something like putting a finite bunch of monomers in a bundle, so that they're not a polymer, just in the presence of other monomers, but don't quote me on that. A dimer is a molecule formed by two identical molecules. Basically, if you can split it into two molecules exactly the same, it's a dimer. ~Deadly-Bagel (talk)

From the oligomer article: In chemistry, an oligomer consists of a finite number of monomer units (ολιγος, or oligos, is Greek for "a few"), in contrast to a polymer which, at least in principle, consists of an unbounded number of monomers. -- WillWare (talk) 00:05, 25 February 2008 (UTC)

monomer - one molecule, dimer - two molecules bonded, trimer - three molecules, etc. Cracking is the process of taking bigger molecules and turning them into smaller molecules. In petrochemicals it is commonly used to produce ethylene, propylene and some C4 products. Cracking a molecule in two does not produce a "dimer" as a "dimer' is formed from joining two things together. - Harrumph —Preceding unsigned comment added by 141.227.3.1 (talk) 17:10, 30 May 2008 (UTC)

Links

The first two reference links in the article are broken, most likely due to a site reorganisation at the destination site. Does anyone have the correct links for the references cited? Cefiar (talk) 22:35, 15 February 2011 (UTC)

Recycling part unclear

The part about recycling seems unclear. Is it talking about mechanical recycling or not? I'd fix it but I have no idea what it's trying to say. — Preceding unsigned comment added by 184.163.9.163 (talk) 23:44, 2 May 2012 (UTC)

Recycling here applies to commercial and industrial rather than backyard composting recycling. The text is currently explaining the thermal (heat-based) recycling by melting it down and re-purposing or hydrolysis. The problem is that this cradle-to-cradle recycling is doubtful and personal use has shown that degradation of the material does occur with repeated changes. ChrisGualtieri (talk) 00:14, 19 June 2015 (UTC)

No, the article describes chemical recycling where the plastic is broken down to it's monomers for repolymerization. Melting would probably still be considered mechanical recycling I guess? Unless the intent is to break it down rather than just melt/reform it.

See https://link.springer.com/article/10.1007/s10924-016-0777-4 and http://www.plasticsrecyclers.eu/chemical-recycling

Blaedd (talk) 20:10, 11 March 2018 (UTC)

When chemically breaking the polymer back down to the monomer and purified, the monomer is indistinguishable from non-recycled monomer by definition. If a different material was formed, it would have a different chemical structure and wouldn't even be named the monomer. The only thing I would question would be the form of the monomer: whether it retains the same D or L form when broken down. — Preceding unsigned comment added by 165.225.34.164 (talk) 17:10, 21 December 2018 (UTC)

Bio-degradable

Poly-lactic acid does not bio-degrade naturally and thus the first line of the article is incorrect:

http://www.biosphereplastic.com/biodegradableplastic/uncategorized/is-pla-compostable/

Thats not going to work as a citation; since it comes from a company that sells 'bio degrader' additives for plastics. The second sentence on that page gives them away rather badly; in their opinion PLA is a plot by big oil to keep control of the plastics industry.

Bidegradation of PLA is not as great as many want to believe, but is well described. try: http://www.material.chula.ac.th/Journal/v18-2-2/83-87%20RUDEEKIT.pdf

"In conclusion PLA sheet would degrade completely under real and controlled composting conditions, whereas the degradation of the PLA sheet under natural landfill and waste water treatment would required a longer time."

EasyTarget (talk) 15:44, 30 November 2017 (UTC)

It seems blatantly obvious that the labeling "biodegradeable" is used by commercial interests. That alone should be enough to change it to a descriptor that is a little more precise such as "biodegradeable under a controlled setting using higher temperatures than is common using backyard composting methods or no methods". My question (I don't edit articles often) is why is there no article "edit" function/link for that first line? (asks the noob) Crgrove (talk) 21:53, 23 January 2019 (UTC)

Requested move 5 August 2016

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: Not moved, oppose not countered for 6 days. (non-admin closure) — Andy W. (talk · ctb) 20:16, 13 August 2016 (UTC)

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Polylactic acid → Poly(lactic acid) – It is the correct technical spelling for this compound. Wipur (talk) 19:44, 5 August 2016 (UTC)

• Oppose per [[WP:RECOGNIZABLE], WP:CONCISE, WP:COMMONNAME, and WP:JARGON: This is only one of three (so far) reliably sourced ways to name this compound, is not the most commong, but is the most obtuse and confusing to our readers.  — SMcCandlish ☺ ☏ ¢ ≽^ʌⱷ҅_ᴥⱷ^ʌ≼  05:15, 7 August 2016 (UTC)

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The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

PLA flammability

PLA flammability information is not superfluous for this article. 80.243.6.98 (talk) 11:59, 27 February 2019 (UTC)

SciFinder report

According to Chemical Abstracts: "references (51469)>refine "Review" (1625)>refine "2014-" (348)". i.e. a review appears about weekly on this material.--Smokefoot (talk) 11:59, 26 September 2019 (UTC)

Tensile strength

Under the Physical Properties section it says "The tensile strength for 3D printed PLA was previously determined."

Could the article be improved by quoting what the tensile strength was determined to be? I'm not an expert so don't want to make the edit myself.

Also does anyone have info on what the repeated stress properties are, eg under compression, vibration, etc? 148.252.132.34 (talk) 17:45, 6 August 2023 (UTC)