Is it dispersed in the porogen used or precipitated as a powder? When I prepare it, the prepared polymer precipitate in the bottom of the flask with a light rubbery consistency? when it dries out after washing it is powder. Is that correct?
Yes it is correct. As the MIP is highly crosslinked it has to precipitate. Further the entrapped solvent makes it rubbery. During drying, solvent evaporates and you get dry powder. It has to be ground mechanically by using pestle mortar or ball bill or also a grinder. If you want you may use molecular sieve to get uniform sized powder.
but the precipitation method is supposed to give polymer spheres of uniform size, I though grinding is not necessary?
The polymer spheres are obtained in case of suspension or emulsion polymerization of polymer. For uncrosslinked polymer you can get powder. One more thing to remember: If molecular weight is very high you get lump. In this case you have crosslinked polymer whose molecular weight is very high. In another case, when the Tg is very low you get rubbery product
In case of high degree of crosslinking, you might face the situation of a single block having the sahpe of the reactor. In this case you have to break the glassy reactor and grind the MIP.
With my personal experience, I found that the physical nature of the polymer formed also depends upon the type of solvent we have chosen, it can be in gel form or in a solid particulate form based on the solvent we use.
when I have prepared MIP in acetonitrile and DMF separately, I got a gel in DMF and a precipitate in ACN.
I am using a mixture of ACN and DMSO and tripled their volume with the same used amount of crosslinker and monomer and I still get that rubbery mass but with turbidity this time, Do you think if I increased the shaking speed it would differ?
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