I have to synthesis a polymer. I want to purify it but that polymer precipitate couldn't dissolve in majority of the organic solvents (acetone, hexane, ethyl acetate, diethyl ether and so on). It showed partially dissolved in DMSO solvent. So any method to purify it?
Firstly the solubility of your polymer strongly depends on the chemical structure. But you can try very hard alkaline medium. That was a solution for some polymers which I synthesized.
Dear all;
try recrystallization, the solvents you mentioned seem to be good non-solvents at ambient temperature, so you should reflux your polymer in any of the mentioned solvents and upon cooling down it will recrystallize or precipitate. You should also have an idea on the main chemicals considered as impurities to screen-up the most appropriate non-solvent. This is easy if you have done the synthesis by yourself, since all residuals are considered as impurities (monomer, initiator/catalyst, solvent,...), than you will find the best solvent for them to insure their retention upon cooling down. Regards
In purifying polymers one has to find a solvent and a non-solvent which will selectively precipitate your polymer or the impurities. If your polymer is completely insoluble in any solvent (may be cross linked), one of the options you may have is to place it in a soxlet apparatus and extract the impurities out using a solvent that your impurities are totally or either partially soluble in.
Depends on what your impurities are?
If they are monomers they as Roshan suggests soxhlet extraction is a simple effective procedure.
If it's salts soxhlett extraction with water could also be effective.
If you're trying to remove oligomers of lower chain length then soxhlet could work if you can find a suitable solvent.
Dear all;
in my first answer I limited my answer to the case of polymer purification by precipitation, and since it is mentioned the soxhlet extraction, then it is also worth to mention the membrane dialysis purification technique, providing you know the molecular weight of your polymer to choose the appropriate membrane molecular weight cutoff. Regards.
I understand that your polymer has a very limited solubility. Considering that the impurities are more soluble you could try to extract than by a conventional extraction method, such as Soxhlet extraction.
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