Talk:Living polymerization

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This article was the subject of an educational assignment in 2014 Q1. Further details were available on the "Education Program:University of Michigan/Chem538 Organic Chemistry of Macromolecules (Winter 2014)" page, which is now unavailable on the wiki.

To my knowledge, Ziegler-Natta polymerization is not considered neither anionic nor living, and it was not Ziegler and Natta who first proposed and showed the existence of living polymerization. As far as I can remember, the first experiments on anionic living polymerization were polystyrene polymerizations.

I have now fixed this, but the section needs to be expanded.

Selenide

The Selenium-Centered Radical-Mediated Polymerization section might be better incorporated in with the Iniferter section. As the conditions of control are under photoinitiation and not thermal conditions. However it does fall nicely in the list of organo chalcogenides, before Tellurium.

Al 07:04, 24 August 2006 (UTC)[reply]

The section on iodine transfer polymerization needs to be expanded. I'll do this in a few days.Delmlsfan 22:12, 24 November 2006 (UTC)[reply]

Done. Delmlsfan 00:34, 1 December 2006 (UTC)[reply]

Living / "Living"

Living polymerization in the literature is often called "living" polymerization or controlled polymerization

is this a tautology? What does this line contribute to the article?

There was an upsurge in interest in living polymerisation in the ‘80s when radical chemistry was applied to the then established living polymerisation techniques involving, anionic, coordination or group transfer mechanisms. Living radical polymerisations (LRP) do not meet the requirements of the term “living” as defined by Szwarc. Since they involve radicals as intermediates they must involve a finite amount of termination. They were therefore considered less “alive” than that of the classical living polymerisation techniques and were therefore referred to as pseudo-/quasi-living, controlled rather than living or living was surrounded by quotations or placed in italics.

The term "living" and what it implies for polymerisation has still not really been resolved, regarding radical polymerization, thus they have placed quotations around the word to signify that the term isn't fully correct but that the effects observed are close enough to the desciption of the term "living".

If you have access to the literature a good discussion is found in the special issue in J. Polym. Sci., Part A: Polym. Chem. (Percec, V.; Tirrell, D. A. J. Polym. Sci., Part A: Polym. Chem. 2000, 38(10), Special Issue: Living or Controlled?). Also (Szwarc, M.; Levy, M.; Milkovich, R. M. J. Am. Chem. Soc. 1956, 78, 2656-2657. and Szwarc, M. Nature 1956, 178, 1168.)

Al 08:46, 30 May 2007 (UTC)[reply]

Split page?

There is a lot of detail on living free radical polymerization. Should it get its own page? Delmlsfan (talk) 01:46, 8 March 2008 (UTC)[reply]

This Article is Vague and Seems to Be written Like a Blurb

The article is very vague. few of these methods have a good article themselves, and so an increased level of information would be desired.

discuss the fundamental concepts behind LFRP:

1) initiate all chains at the same time. this is done in a few different ways, but one way is to heat the reaction mixture up so that the half life of the initiator is very short. then cool it down again to prevent initiator molecules from continuing to initiate chains at later stages

2) chains grow at the same rate because they are all inhibited by a catalyst or inhibiting agent like nitroxide or Thio species.

3) very little, if any, chain combination termination. why? These capped chains grow slowly. they are reversibly bound to an inhibitor. this effectively limits the duration during which an active organic radical is in solution. basically: capped ---> unbound radical ---> growth by a few monomers----> capped.

this means that it is VERY unlikely that 2 conditions are met at the same time and at the same point in space. 1) that a chain is currently "uncapped" or "active" and 2) that this active chain is CLOSE TO another active or uncapped chain (which would be required for 2 chains to combine).

this is how the PDI is kept low (although it is still extremely difficult to get a PDI< 1.1 using these methods)

4) the polymerization can be stopped by cooling the mixture. with NMP and RAFT, this results in a thio or nitroxide "capped" polymer chain. at low temperatures, these species are completely inactive.

you can store these dormant chains, and bring them out a week later and add more monomer, or different monomer, and continue the polymerization.

ALSO: even a SINGLE mechanism would be desireable.

the question then becomes: why dont YOU (me) edit the article yourself? because it would sound like the insane ramblings of a grad student who has had too many undergraduates ask him stupid questions.70.177.16.146 (talk) 21:45, 24 October 2008 (UTC)[reply]

Sounds exactly like what I learned from Hawker's polymer class when this post was written... hmm....2601:602:CB00:94A0:6CA7:7100:3836:B8AF (talk) 07:26, 27 October 2021 (UTC)[reply]

Link to CCT and CMRP

Smokefoot & V8rik, You are right. It's changed back to the original, but included are links to the more specialized CCT and CMRP topics:

http://en.wikipedia.org/wiki/Catalytic_Chain_Transfer. http://en.wikipedia.org/wiki/Cobalt_Mediated_Radical_Polymerization Please have a look; comments are welcome. (Bruintje71 (talk) 21:24, 10 June 2010 (UTC)).[reply]

Thanks, I am looking forward to the new articles. V8rik (talk) 22:25, 7 June 2010 (UTC)[reply]

THF

What is THF? This abbreviation is used undefined. peter (talk) 00:35, 13 April 2011 (UTC)[reply]

The problem was that the initial mention of THF was not bracketed to be a link. Nevertheless, the reader should not have to go to a separate encyclopedia article just to find out what an abbrev stands for. peter (talk) 00:34, 13 April 2011 (UTC)[reply]

Peer reviews for WikiChemist2013 Updates

Peer Review #1

In general, I think this page is a good expansion of the original article, but there is some work to do. The page can benefit from a more general discussion of living polymerizations for non-experts. The text can be more suited for a non-expert by describing the advantages, disadvantages, and applications of each living polymerization. I think the Characteristics section is a good start for making the Wikipedia accessible to non-experts, and these types of characteristics should also be pointed out for each of the living polymerizations. There is an overwhelming amount of journal sources, and some more reviews and books should be added. You can find several books online that provides more general information, one that I found useful that was not used as a reference on the Wiki page is called Controlled and Living Polymerizations: From Mechanisms to Applications (Online ISBN: 9783527629091). Lastly, it needs to be proofread.

Most of the introduction paragraph was untouched from the original page, which is fine since the intro paragraph was already clearly written and accessible to non-experts. However, the introduction can be significantly expanded. One sentence was added explaining why living polymerizations are desirable; this sentence can be expanded on by providing an example. Although there is a separate application section, it would be helpful to name some industrial examples right away in the intro.

Some of the introduction was moved into its own History section. I think this is a great idea, but this section needs improvement. It becomes less accessible for non-experts and more of a list polymerization reactions. The History section would be more accessible for non-experts if the authors worded this section more in terms of the development of living polymerizations. Mainly answer the question of why these named reactions are important to the development of living polymerizations.

Another thing you might want to include in the introduction is to establish the difference between controlled and living polymerizations. When you search for controlled polymerizations on Wikipedia, you are redirected to living polymerization articles. It’s stated later in the article that the difference is debatable, and I think this could be stated right away in the introduction. Stating this right away would help clarify some of the sections that aren’t technically considered living and a few sentences establishing the difference in the introduction would be helpful to readers searching for controlled polymerizations.

The sections under Living Polymerization Techniques and Applications were significantly expanded on from the original article. Ring-opening, free radical, and catalyst-transfer are all well done sections that seem like an appropriate summary for Wikipedia. There are a few sections that can be re-written in more general terms to be more accessible to non-experts. First, the section on alpha-olefins has a lot of scientific terminology without links or pictures. A non-expert may not know what PE and PP stand for. A non-expert probably won’t understand why chelate initiators have high potential for living polymerization of alpha olefins. The other section that needs work is group-transfer polymerization. It seems as though Ziegler-Natta and group transfer were combined from the original article but neither section was altered. This section could benefit from a more general discussion describing these types of living polymerizations.

The important terms and concepts are linked to their respective Wikipedia pages, and the authors also included some good external links. However, there are some broken links (alpha-olefins, Kumada Coupling, and step-growth are just the ones I caught). All of the examples seem appropriate, however, the organization is slightly confusing. It is not clear why living ring-opening metathesis polymerization is under the category of anionic polymerization. There are pages for some of the categories you talk about, like Living Anionic Polymerization and Living Free-Radical Polymerization, but I think your page is a good, complimentary summary of these pages.

The figures are well made. The only one I would edit is the large mechanism under catalyst-transfer. Maybe breaking it up into two separate pictures would help. Currently, it is hard to follow what is going on in the picture and the description in the text. I also think figures should be added to Living alpha-polymerization, and living group polymerizations. Otherwise, I thought the animation describing the characteristics of living polymerization was pretty clever and helps describe the ideas, the pictures in the applications section are well done, and as far as I can tell the ChemDraw structures are chemically accurate, however, some of the atom labels are small and difficult to read. Iriidium (talk) 03:35, 28 February 2014 (UTC)[reply]

Peer Review of Living Polymerization Wikipedia Page

Content: I really like the breakdown of your sections and you definitely did a lot of great work adding to your page. Your introduction looks good, but I feel like more could be added to help someone who has never heard of living polymerizations to understand exactly what they are and how they are different from other types of polymerizations. This would also add/update the introduction section a bit more in terms of the content and its ability to help the reader understand the basics of living polymerizations. In the history section you might discuss more recent advances after 1979 as well as go a little deeper into what the relevance of those advances are. In addition, I notice that you have a few places in your page where you left brackets or things that you might have been using as a place holder, but forgot to delete. Also in the history section you use the term "livingness," I'm not sure if this is the right was to get across the fact that there are several methods that exist which make Ziegler-Natta polymerization living. I also feel like people who don't know anything about living polymerizations might get confused when you jump into characteristics after the introduction. Is there any way to put a little bit of general information about the mechanism of living polymerization and some basic information first? On the other hand, the characteristics section does a great job at describing the benefits of living polymerizations. You should delete the question mark at the end of the section titled "Living group-transfer polymerization?". Some of your links are red because they are not actual wiki pages, or you typed it in wrong when trying to link the page, you should go back and check those. The examples you give a good. Overall I feel like the page contains great information especially in the applications and techniques sections.

Figures: I really like how some of your figures are interactive. All of your figures look good, but I would be careful with making figures hard to read or interpret. Also, some of your figures could be smaller and aligned better (I'm referring to the second figure in the "Low dispersity" section).

References: You have extensive references in your page, much more than the page has currently. On the other hand, I would try and add more references that are actually attainable by the Wiki audience, like books.

Overall Presentation: Overall, the page is greatly improved when compared to the current page. Content is well described and written, with the exception of a few places that could use more elaboration or explanation. Figures are good, especially the interactive figures, but the alignment and size of some can be adjusted to make them more pleasing to the eye. Other than that, I think your references are great but could use a few more non-journal sources that Wiki readers can access.

Thanks :-) Schrodingerscat101 (talk) Schrodingerscat101 (talk) 04:31, 28 February 2014 (UTC)[reply]

Instructor Comments

The peer reviewers did an excellent job pointing out a lot of the places where further editing is needed. I would eliminate the initiation sequence in the catalyst-transfer polycondensation section since this is specific to one type of catalyst (LnNiCl2), which has been largely replaced now. I am also not sure what the self-healing example adds to the page. Or at least, the connection to living polymerizations was not abundantly clear. Otherwise, nice job! UMChemProfessor (talk) 03:30, 3 March 2014 (UTC)[reply]

Suggestions from ChemLibrarian

A few suggestions here.

The quote box for "IUPAC definition" looks a little awkward in terms of location. Please see this page Template:Quote box to change the wrapping and location of the quote box to make the article flow better.
Don't forget your (add reference?) note in the first paragraph.
Nice work with the animation. But please edit the location and size of the images to make the texts wrapped nicer around them. See Wikipedia:Picture tutorial for tips on doing it.
There are several errors in your reference list. Mostly caused by author names. If you were using the template to insert the references, when there are multiple authors, just input all of them into the Coauthor field and do not use the First name and Last name fields. That may help.

ChemLibrarian (talk) 16:40, 3 March 2014 (UTC)[reply]

Response to reviewers

Thank you for taking the time to review our Wikipedia page we have taken the comments into consideration when editing our page.

Response to Iriidium

We attempted to point out some of the characteristics of living polymerization in the examples given particularly in the alpha olefin section. These changes were based on your comments about making the alpha olefin section more accessible to the Wikipedia readers. As for the comment on the references, we added mainly review articles and books to the reference list and many of the journal articles were copied over from the already existing page. We addressed your comment comment about making the introduction more clear by elaborating on the difference between living and non-living polymerization as well as living vs controlled polymerization. However we felt that significantly expanding on the introduction with examples would make it too long. We agreed with your comment on reorganizing and expanding upon the history and as a result the history section was reorganized and content was added. The alpha olefin section was expanded on by adding images and trying to explain why the chelate initiators have a high potential for living polymerization. We also fixed the issue you mentioned about ROMP by removing it from anionic polymerization and making ROMP its own section since it can be either anionic or cationic. We also fixed the CTP image by eliminating the initiation step in order to make the image more clear. Thanks Charco0917 (talk)WikiChemist2013 (talk)

Response to Schrodingerscat101

Thank you for your comments regarding our sandbox page. We attempted to make the definition of living polymerization (LP) more clear for new readers by elaborating on the differences of LP with non-LP. As for your comment about including more detailed and recent examples in the history section, we organized the section but did not add more recent examples since the histroy of LP was not the main focus of our page. We have realigned and made our images more easy to interpret and the broken links were fixed. Many of our references are available through google books, public content or are major reviews in the field. Thanks Charco0917 (talk)WikiChemist2013 (talk)

Response to UMChemProfessor

Thanks for taking the time to review our page. We added a additional explanation to the self-healing polymer section and how it relates to living polymers. In addition we removed the initiation step from the CTP mechanism in order to make it more clear to understand. Thanks Charco0917 (talk)WikiChemist2013 (talk)

Response to ChemLibrarian

Thank you for your comments on our page. The reference errors were fixed and some of the images were re-sized/re-positioned to make the text wrap around the figures better. Thanks Charco0917 (talk)WikiChemist2013 (talk)

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