The first is to check the presence of crosslinked structure. You should choose a good solvent. It the polymer dissolves before crosslinking and only swells afterwards, you got a crosslinked structure. Using the same solvent and Soxhlet extraction you can remove the soluble fraction and after drying and measuring the weight of the solid residue you can get the gel fraction. You can study the effect of crosslinking conditions, parameters on the gel fraction. In some cases (but not always) the crosslinking process can also be monitored by IR spectrocopy

The first is to check the presence of crosslinked structure. You should choose a good solvent. It the polymer dissolves before crosslinking and only swells afterwards, you got a crosslinked structure. Using the same solvent and Soxhlet extraction you can remove the soluble fraction and after drying and measuring the weight of the solid residue you can get the gel fraction. You can study the effect of crosslinking conditions, parameters on the gel fraction. In some cases (but not always) the crosslinking process can also be monitored by IR spectrocopy

Dear all;

generally physical properties are altered by crosslinking; such as for example the glass transition temperature Tg and density. So; it is possible to compare these properties with those of the virgin (uncrosslinked) polymer. Regards

@R Fauzi: if you were able to share the type of crosslinks you expect / the chemical nature of your polymer, it might be easier to have a more targeted answer.

Excellent answer from @G. Banhegyi.  May I add, we have previously gained a lot of information on the reactions that are happening by looking also at the sol fraction (the solvent dissolvable portion).  If there was a crosslinking reaction that happened also on the sol fraction, then you are in luck, since the sol fraction can be subjected to a lot more analytical testing (solution NMR, GPC, MALDI, etc) than the gel fraction.  Of course, the sol fraction would not have many crosslinks (if it did, it would be part of the gel fraction!) so the information you can gain isn't all-encompassing.  But considering the ease with which you can probe the sol fraction, I would recommend it.

I am agree with the before answers, but it also can be observed by  Rheological analysis or torque rheometry. I am agree with the soxhlet extraction method, since this method is quantitative and you can find the gel content.

If u can provide the names of polymer and cross-liker used than it will be easily analysed. sometimes even the color change shows the formation of crosslinked polymers.

1. partioning of protein or polymer will give the information of pore size distribution

2. DLS will give the information of correlated length of crosslinked network

I think that you can have the FTIR spectra for the non cross linked polymer and compare it with the spectra of your samples... according to the shift of functional groups peaks you can figure out if the polymer was cross-linked or not....I agree with prof. Banhegyi for the dissolution and swelling test.

I agree with Gyorgy Banhegyi.  If your polymer is actually a polymer compound that includes fillers, additives, or other polymers, then it gets tricky.  You'll need to understand how those partition between sol and gel phases and if retained by the Soxhlet thimble.  Additionally, your question is vague so it is hard to know exactly how to answer, but Gyorgy's answer assumes a homogeneous material.  In many commercial plastics, for example, there can be small fractions of crosslinked polymer that are residues of thermo-oxidation during processing, and these may be highly crosslinked "gels".  In that case, the level is too low for accurate detection by Soxhlet extraction.  Typically, optical methods are used such as laser scanning of films.  My guess, though, is that this is not what you were referring to, and yes, for typical laboratory prepared polymers an extraction method is generally best.  Be sure to extract to constant mass with a proven good solvent for your polymer.

Thank you very much for the valuable answers and responds. Regarding to the above question, the chosen monomer is acrylic acid and the crossliker is Bis-acrylamide. i just want to produce a polymer solution with low crosslinking structure.

You can detect the degree of cross-linking by checking the swelling capacity of your polymer. And you can also try triethylene glycol divinyl ether as a cross-linking agent for acrylic acid.