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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 13 of 13. This is the beginning of the thread.
Posted by ace on October 23, 2003, at 21:27:36
Any chem scholars out there!?
Can anyone recommend me a good site on polymerization- I have searched the net heaps but am yet to find one!
Condensation polymers are what I'm focusing on most...
BTW, in addition (chain-growth) polymerization only one off the pi bonds (of the double bond) is broken...right? This holds true for EVERY addition polymer?
Ace.
Posted by galkeepinon on October 23, 2003, at 22:10:14
In reply to study help with chemistry!, posted by ace on October 23, 2003, at 21:27:36
Hiya ace!
>>>>Can anyone recommend me a good site on polymerization- I have searched the net heaps but am yet to find one!
Try this:
http://www.specialchem4polymers.comAlso, there is a great book about functional condensation polymers entitled:
"Functional Condensation Polymers"
by Charles E. Carraher
Speaking of scholars, I did schoolwork ALL dang day! Nice life eh? LOL
Is this a homework board now? ;-)
Anyway~hope this helps ya somewhat.
Take it easy buddy!
Posted by Larry Hoover on October 23, 2003, at 22:43:01
In reply to study help with chemistry!, posted by ace on October 23, 2003, at 21:27:36
> Any chem scholars out there!?
>
> Can anyone recommend me a good site on polymerization- I have searched the net heaps but am yet to find one!http://mrcemis.ms.nwu.edu/polymer/
> Condensation polymers are what I'm focusing on most...
Here's a condensation polymerization page:
http://mrcemis.ms.nwu.edu/polymer/4-condensation.html
By definition, a condensation reaction produces water as a secondary product, so the reactive sites must donate either -OH or +H.
> BTW, in addition (chain-growth) polymerization only one off the pi bonds (of the double bond) is broken...right?
Yes, or elsewise there would be no chain formed.
> This holds true for EVERY addition polymer?
Consider acetylene (triple bond).
> Ace.
Lar
Posted by Larry Hoover on October 23, 2003, at 22:51:28
In reply to study help with chemistry!, posted by ace on October 23, 2003, at 21:27:36
> Any chem scholars out there!?
Ya, but this one shouldn't answer posts half an hour after he's taken his sleep meds.
> Can anyone recommend me a good site on polymerization- I have searched the net heaps but am yet to find one!
http://www.psrc.usm.edu/macrog/synth.htm
> Condensation polymers are what I'm focusing on most...Condensation polymers can also yield other H-X byproducts other than water, like HCl. I guess polymer chemists expanded the term used by organic chemists like me.
> BTW, in addition (chain-growth) polymerization only one off the pi bonds (of the double bond) is broken...right? This holds true for EVERY addition polymer?
>
> Ace.An addition polymer is simply a polymer where the whole monomer molecule enters the product. Not all monomers that polymerize have pi bonds. The monomer that goes into nylon doesn't for example.
Lar
Posted by Tabitha on October 24, 2003, at 0:07:54
In reply to Re: study help with chemistry! more!, posted by Larry Hoover on October 23, 2003, at 22:51:28
> An addition polymer is simply a polymer where the whole monomer molecule enters the product. Not all monomers that polymerize have pi bonds. The monomer that goes into nylon doesn't for example.
>
> LarOh Larry Hoover-- I love it when you talk geek ;-)
Posted by ace on October 24, 2003, at 0:12:50
In reply to Re: study help with chemistry! more!, posted by Larry Hoover on October 23, 2003, at 22:51:28
> > Any chem scholars out there!?
>
> Ya, but this one shouldn't answer posts half an hour after he's taken his sleep meds.That's a lesson for you!
> > Can anyone recommend me a good site on polymerization- I have searched the net heaps but am yet to find one!
>
> http://www.psrc.usm.edu/macrog/synth.htm
>
> > Condensation polymers are what I'm focusing on most...
>
> Condensation polymers can also yield other H-X byproducts other than water, like HCl. I guess polymer chemists expanded the term used by organic chemists like me.Methanol is 'condensed out' too sometimes?
> > BTW, in addition (chain-growth) polymerization only one off the pi bonds (of the double bond) is broken...right? This holds true for EVERY addition polymer?
> >
> > Ace.
>
> An addition polymer is simply a polymer where the whole monomer molecule enters the product.So, as opposed to condensation polymers, we have no loss of ANY atoms? And if an aromatic ring is involved in the polymerization it remains intact...ie it doesn't form an aliphatic chain?
The benzene ring just 'hangs of' another chain ?(assuming the polymer is made of 2 monomers)Not all monomers that polymerize have pi bonds. The monomer that goes into nylon doesn't for example.
> Lar
Thanks mate!,
Ace.
Posted by ace on October 24, 2003, at 0:18:56
In reply to Re: study help with chemistry! ?ace, posted by Larry Hoover on October 23, 2003, at 22:43:01
> > Any chem scholars out there!?
> >
> > Can anyone recommend me a good site on polymerization- I have searched the net heaps but am yet to find one!
>
> http://mrcemis.ms.nwu.edu/polymer/
>
> > Condensation polymers are what I'm focusing on most...
>
> Here's a condensation polymerization page:
>
> http://mrcemis.ms.nwu.edu/polymer/4-condensation.html
>
> By definition, a condensation reaction produces water as a secondary product, so the reactive sites must donate either -OH or +H.
> > BTW, in addition (chain-growth) polymerization only one off the pi bonds (of the double bond) is broken...right?
>
> Yes, or elsewise there would be no chain formed.But if we have an 'di-ene' alkene only one of the double bonds is broken in the polymerization? I should have stated my question better!
> > This holds true for EVERY addition polymer?
>
> Consider acetylene (triple bond).
>
> > Ace.
>
> LarAlso, we can say that every condensation polymer monomer MUST be di-functional?
Man, I prefer stereochemistry to this!
Thanks for the sites too, Larry.
Ace.
Posted by ace on October 24, 2003, at 0:20:10
In reply to Re: study help with chemistry! ?ace, posted by galkeepinon on October 23, 2003, at 22:10:14
> Hiya ace!
> >>>>Can anyone recommend me a good site on polymerization- I have searched the net heaps but am yet to find one!
> Try this:
> http://www.specialchem4polymers.com
>
> Also, there is a great book about functional condensation polymers entitled:
> "Functional Condensation Polymers"
> by Charles E. Carraher
>
> Speaking of scholars, I did schoolwork ALL dang day! Nice life eh? LOLWhat did you study?!
> Is this a homework board now? ;-)
> Anyway~~hope this helps ya somewhat.
> Take it easy buddy!Thanks so much! Thanks for the sites!
Ace.
Posted by galkeepinon on October 24, 2003, at 1:16:19
In reply to Re: study help with chemistry! » galkeepinon, posted by ace on October 24, 2003, at 0:20:10
>>>>>What did you study?!
One of my courses is called 'Alcohol and Drugs: Misuse, Use, And Addiction'. It's a Writing Intensive course, so I had A LOT of writing to do.>>>>>>Thanks so much! Thanks for the sites!
>
> Ace.No problem ace,
Take care! :-)
Posted by Larry Hoover on October 24, 2003, at 4:56:38
In reply to Re: study help with chemistry! more! » Larry Hoover, posted by ace on October 24, 2003, at 0:12:50
> > > Any chem scholars out there!?
> >
> > Ya, but this one shouldn't answer posts half an hour after he's taken his sleep meds.
>
> That's a lesson for you!Ya. <grumble> Coffee's hitting the brain now.
> > > Can anyone recommend me a good site on polymerization- I have searched the net heaps but am yet to find one!
> >
> > http://www.psrc.usm.edu/macrog/synth.htm
> >
> > > Condensation polymers are what I'm focusing on most...
> >
> > Condensation polymers can also yield other H-X byproducts other than water, like HCl. I guess polymer chemists expanded the term used by organic chemists like me.
>
> Methanol is 'condensed out' too sometimes?I'm not a polymer chemist. I suppose that's possible, but I don't know.
> > > BTW, in addition (chain-growth) polymerization only one off the pi bonds (of the double bond) is broken...right? This holds true for EVERY addition polymer?
> > >
> > > Ace.
> >
> > An addition polymer is simply a polymer where the whole monomer molecule enters the product.
>
> So, as opposed to condensation polymers, we have no loss of ANY atoms?Correct. The polymerization involves rearrangement, almost always via free radical or resonance processes.
> And if an aromatic ring is involved in the polymerization it remains intact...ie it doesn't form an aliphatic chain?
Breaking an aromatic ring is energetically unfavourable. The activation energy would break aliphatic bonds first, so you'd have a complete loss of structure. Yes, aromatics remain aromatics. The electron are more mobile on aromatic substituents, so activation energies are generally substantially reduced.
> The benzene ring just 'hangs of' another chain ?(assuming the polymer is made of 2 monomers)
Yes, which affects the properties of the polymer, to some extent. They tend to be more rigid, if I recall correctly.
> Not all monomers that polymerize have pi bonds. The monomer that goes into nylon doesn't for example.
>
>
>
> > Lar
>
>
> Thanks mate!,
> Ace.
>I haven't thought these sort of thoughts in a while. Thanks for dredging it all up.
Lar
Posted by Larry Hoover on October 24, 2003, at 5:24:19
In reply to Re: study help with chemistry! » Larry Hoover, posted by ace on October 24, 2003, at 0:18:56
> > > Any chem scholars out there!?
> > >
> > > Can anyone recommend me a good site on polymerization- I have searched the net heaps but am yet to find one!
> >
> > http://mrcemis.ms.nwu.edu/polymer/
> >
> > > Condensation polymers are what I'm focusing on most...
> >
> > Here's a condensation polymerization page:
> >
> > http://mrcemis.ms.nwu.edu/polymer/4-condensation.html
> >
> > By definition, a condensation reaction produces water as a secondary product, so the reactive sites must donate either -OH or +H.Just for clarity, organic chemistry presumed water was condensed, but hey! chemists don't always talk the same language, even to each other.
>
> > > BTW, in addition (chain-growth) polymerization only one off the pi bonds (of the double bond) is broken...right?
> >
> > Yes, or elsewise there would be no chain formed.
>
> But if we have an 'di-ene' alkene only one of the double bonds is broken in the polymerization? I should have stated my question better!Polymerization is not always a linear process. A diene could readily cross-link to other chains. You then get a net, instead of spaghetti. Epoxies are an example where that cross-linking process is desired.
The thing with a diene, though, is the symmetry of the monomer comes into play. All pi bonds are reactive, so the resulting polymer can have a diversity of sub-structures within it.
Also, the free-radical process that propogates the polymerization of even a mono-ene (e.g. ethylene, propylene) also permits the abstraction or disproportionation of a proton, allowing a side-chain to graft to the site of abstraction.
This site is a little more advanced than the others. I don't know if you have studied electron push diagrams yet.
http://www.cm.utexas.edu/academic/courses/Fall1997/CH610B/Gilbert/ancillaries/polymers.html> > > This holds true for EVERY addition polymer?
> >
> > Consider acetylene (triple bond).
> >
> > > Ace.
> >
> > Lar
>
> Also, we can say that every condensation polymer monomer MUST be di-functional?Yes, *at least* di-funtional. Consider the quintessential example of amino acids forming polypeptides (proteins). They also cross-link, e.g. via sulphur bridges at cysteine residues. Check the amino acid structures for tri-functionals (e.g. polyamines, polycarboxylics, sulhydryls). It's a very important part of enzyme function. It's the mechanism by which a single change in a single DNA base can lead to vastly different enzyme function.
> Man, I prefer stereochemistry to this!If you can picture enantiomers, in three dimensions, in your brain, then you will be a good chemist. Picturing inversion of a molecule via addition-elimination, the formation of planar intermediates, resonance hybrids, and the like....if you can picture them, you won't ever be confused by them.
The only problem I ever had with stereochemistry was using the CIP rules to develop IUPAC names for complex structures. Thank the Almighty Geek on High for the computer programs that do that for you.
> Thanks for the sites too, Larry.
>
> Ace.Quick google search.....keyword selection is critical.
My pleasure,
Lar
Posted by Larry Hoover on October 24, 2003, at 5:26:38
In reply to Re: Oh! » Larry Hoover, posted by Tabitha on October 24, 2003, at 0:07:54
> > An addition polymer is simply a polymer where the whole monomer molecule enters the product. Not all monomers that polymerize have pi bonds. The monomer that goes into nylon doesn't for example.
> >
> > Lar
>
> Oh Larry Hoover-- I love it when you talk geek ;-)Candle light, soft music, and geek-speak. Now we're talkin'. :-)
Lar
Posted by slinky on October 24, 2003, at 13:11:58
In reply to Re: Oh! » Larry Hoover, posted by Tabitha on October 24, 2003, at 0:07:54
> > An addition polymer is simply a polymer where the whole monomer molecule enters the product. Not all monomers that polymerize have pi bonds. The monomer that goes into nylon doesn't for example.
> >
> > Lar
>
> Oh Larry Hoover-- I love it when you talk geek ;-)
Polymers do it for me too.Is there a monomer in fishnet stockings?
It's sexy when someone is talking technical Refreshing to get some testosterome.
Polymerize me...please
This is the end of the thread.
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