Non-uniform phase structure in immiscible polymer blends - reasons and consequences

Uniformity of the phase structure in binary and ternary polystyrene, polyamide and polyethylene blends was studied. It was found that areas containing particles with strongly different average size coexisted in quenched and compression molded samples of all blends under study. It was shown that neglecting of this effect could cause erroneous determination of the particle size dependence on the mixing conditions and properties of the blend components. An analysis of the competition between the droplet break-up and coalescence showed that non-uniformity of the phase structure was apparently caused by non-uniform flow field in a mixing device.