Talk:Polylactic acid

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

Contents

[edit] 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.

"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)

[edit] 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)

[edit] 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)

[edit] 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)

[edit] 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)