A practical guide to polymer miscibility

In this paper a general guide to polymer miscibility is presented. The view taken here is that in many polymer systems mixing can be predicted on the basis of a simple balance between unfavourable ‘physical forces’, described in terms of non-hydrogen bonded solubility parameters, and favourable specific interactions. In essence, the closer the values of the two solubility parameters and the greater the relative strength of the potential intermolecular interactions present between the polymeric components of the blend, the greater the probability of miscibility. This is discussed in terms of critical values of the interaction parameter, χCrit, and the upper limits of the non-hydrogen bonded solubility parameter difference, Δδ. It is then demonstrated that this approach can be applied to the prediction of trends in miscibility for a wide range of binary polymer blend systems.