Concerted Precipitation from Solution

If two different polymers can be dissolved successfully in a common solvent, a molecular intermixing of the dissolved macromolecules should occur due to the fast establishment of the thermodynamic equilibrium. The difficulty with this procedure is due to the fact that very many polymers become incompatible above a certain concentration when their solutions in a common solvent are combined. This means that the originally homogeneous solutions of polymers A and B separate into two phases when being combined, whereby each of the phases contain different quantitative proportions A B [e.g., polystyrene and poly(vinyl acetate) in toluene]. But even when two polymers have been dissolved sue- 

PMMA/PS Partially miscible system Toluene Opaque 120 and 105 

PS (polystyrene), PVC [poly(vinyl chlraide)], PC (bisphtaiol A polycarbonate), PMMA [poly (methyl methacrylate)], PB (polybutadiene), SAN (styrene-aCTylraiitrile copolymer), NBR (acrylonitrile-butadiene rubber), PPE (polyphtaiyltaie ether) 

---