I am trying to remove NaOH salt from a thermoset polymer powder that I synthesized. The polymer is water soluble. How can I remover the salt from the powder?
Dear Tb Bo,
You can try dissolving your polymer in water at appropriate concentration and put it inside a membrane dialysis bags (membrane cut off (pore size) to be used will depends on the Mw of your polymer). if your polymer is high Mw you can use 10-30-50 kDa COff membranes and for low Mw polymer you can use 1000-3000 Da Coff membranes. Then put the membrane bag containing your dissolved mixture in a recipe with distilled water and stir the water for speed the osmosis process. Change the water several times in the day and 2-3 days will be enough for having your polymer free of NaOH. You can also use dialysis devices commercially available.
Another approach is to prepare a concentrate polymer solution (3-5% w/v), adjusting pH to 7 with HCl (at slightly lower concentration than NaOH used in your synthesis) and then precipitate it with a non solvent solution (e.g. acetone), Typically adding 5 volume of non solvents per 1 volume of solution. Then centrifuged the solid and washed with ethanol mixtures (70, 80, 90 % v/v) . The number of washes will depends on the amount of Chloride ions that will remains after each washing step and that can be monitoring adding a drop of AgNO3 to the solution . Finally , absolute ethanol is added to the solid washed and then dried at room temperature.
The third option is to use a cationic exchange resin and put it in contact with a polymer solution because you want to remove the Na+ ion mainly.
Hope it could help you,
Best regards,
Gustavo
Dear Tb Bo,
I agree with the answer that suggested by Dr. Edwin A. Murillo
Good luck
Dear Gustavo Cabrera
if i have a cross-linked polymer, can i remove salt by using dialysis bags?
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