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.
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> > Lar
>
>
> Thanks mate!,
> Ace.
>I haven't thought these sort of thoughts in a while. Thanks for dredging it all up.
Lar
poster:Larry Hoover
thread:272472
URL: http://www.dr-bob.org/babble/social/20031020/msgs/272594.html