I am trying to put into place crosslinked polymers through varied radiation and thermal treatments which eventually is going to allow me to have polymers with different degrees of crosslinking and I was wondering how can I measure that? Or put it into evidence?
Dear Amal Ben Hadj Mabrouk, the most widely used technique in measuring crosslink density is swelling. It is even standardized in some testing standards such as ASTM. My Regards
In addition to the determination of cross-link density using Flory-Rehner equation, you can also use the value of the rubbery plateau modulus of dynamic mechanical spectrum of your sample. In case it is not easy to observe the rubbery plateau, which can sometime happen, you can use the storage modulus at Tg + 50oC. You can then use Flory's rubber elasticity theory to calculate the crosslink density. This theory applies to moderately cross-linked materials such as rubbers. In case you are interested in materials with relatively high cross-link density with glassy properties, such as epoxies, you can use modified Flory equation, such as the one proposed by Lawrence E. Nielsen. Be careful, the Nielsen equation changes depending on what storage modulus (E': tensile modulus, or G': shear modulus) you use.
Hi;
Gel fraction determination by leaching test.
My regards
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