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GPC of hardly soluble polymer
Posted: Wed Oct 10, 2012 2:20 pm
by push
Hi,
In order to perform GPC I need to dissolve a polymer.
If it is insoluble how can I prove whether it is crosslinked or not?
Thanks
Re: GPC of hardly soluble polymer
Posted: Wed Oct 10, 2012 6:25 pm
by Gerhard Kratz
First try to do ultrasonic your polymer with your solvent. Second try to find another solvent. Beside THF you can use other solvents like DMF or others.
Re: GPC of hardly soluble polymer
Posted: Wed Oct 10, 2012 7:47 pm
by chromatographer1
Some others may require fairly high temperatures (above ambient).
Toluene and MEK are possibilities for other solvents.
best wishes,
Rod
Re: GPC of hardly soluble polymer
Posted: Tue Oct 16, 2012 2:08 am
by drewa512
You can use DSC to show there is no melting peak which proves full cross-linking. There is also the ASTM swell test...which is a bit wonky to be honest. What polymer is this?
Re: GPC of hardly soluble polymer
Posted: Tue Oct 16, 2012 7:39 am
by gstaepels
The problem with GPC is that the sample must be soluble and solvatated in order to reach its maximum hydrodynamic volume (that is what you really determine with GPC). You can do all kinds of tricks to get your sample dissolved, but is it really a solution or an "apparent" solution? The pitfall in GPC is that it will give you a number, but is the number telling you what the molecular weight is? Sometimes, you have to say that it is not possible to determine the molecular weight distribution, especially if it is a cross linked polymer.