Sizes of Particulate Dispersed Phase in Incompatible Binary Polymer Blends Prepared by Melt Blending

Incompatible binary blends such as nylon 6 (PA)/styrene-acrylonitrile copolymer (SAN), PA/polystyrene (PS), PA/polypropylene (PP), SAN/PP, PS/PP and PP/ethylene-propylene-rubber (EPR) were prepared in the molten state using a Brabender-type mixer. The effects of interfacial tension between component polymers, blending compositions, rheological properties of blends and component polymers, and blending conditions on the sizes of particulate-dispersed phases of blends have been investigated. The results clarified that the number-average radius rn of the particulate dispersed phases of blends can be described by the following equation: [rn∝γ12φ2/3dσ-1/2], where γ12, φd and σ denote the interfacial tension between component polymers, the volume fraction of particulate dispersed phase and the average shear stress generated in the mixer, respectively.