Generally speaking, most polymers are either non-crystalline "amorphous" or semi-crystalline "containing a significant amount of disordered domains". For this reason, purification of polymers is not usually done by crystallization in a similar way to that done on simple solid organic compounds.

Purification by precipitation is widespread on laboratory-scale & on industrial-scale. This method starts by selecting a proper solvent and then dissolving the polymeric sample in a minimum amount of this solvent. When dissolution is complete, an excess amount of a non-solvent {one which does not dissolve the polymer} is added with vigorous stirring. The polymer will precipitate out & it can be filtered smoothly.

To exemplify, assume that the polymer to be purified is polystyrene (PS). A number of solvents can dissolve it properly but I used to suggest to my students (in Great Britain long time ago) to select toluene. After the polymer is dissolved, the non-solvent of PS will obviously be a polar one. There are many non-solvents but I used to suggest methanol & it worked very well.

If the polymeric solution has a total volume of 100 mL, then one may use 300 mL of the non-solvent. After filtration, the solvent/non-solvent mixture is subjected to separation (e,g, by distillation) and most of these liquids are recovered for re-use.

Try with sintered glass filter under vacuum.

Thanks alot for your help. but can we purify it through centrifugation