Prediction of the compatibility of polymers and analysis of the microphase compositions and some properties of blends

The calculation scheme for the prediction of polymer compatibility is proposed. The scheme is based on a criterion of polymer solubility in organic solvents that takes into account the chemical structuring of both the polymer and the solvent, surface forces, and the intermolecular-interaction energy between the polymer and the solvent. With the introduction of one polymer into another, one of them is considered a “solvent.” The cases of full compatibility of polymers, partial compatibility, and absolute incompatibility are analyzed. The dependences given for the glass-transition temperature on the compositions of some blends are in good agreement with the experimental data. The possibility to estimate the microphase compositions during microphase separation of the partially compatible polymers is shown. The influence of temperature, the molecular masses of polymers, and their architectures (degrees of branching) on compatibility is studied. It is found that the temperature weakly affects the compatibility of polymers in the glassy state. The effects of the molecular mass and, especially, the degree of branching are substantial. The calculation scheme is computerized, and it is a part of the computer program Cascade (INEOS RAS).