EFFECT OF THE MIXING CONDITIONS ON THE PHASE-STRUCTURE OF PP PS BLENDS/

The effect of the rate and time of mixing in a batch mixer on the phas e structure of polypropylene/polystyrene (PP/PS) blends with various t heological properties of the components was studied. Regions with subs tantially different average sizes of the dispersed particles were foun d in the studied blends. Differences between the average size of the p articles in individual regions of the samples persist in all blends an d mixing conditions under study. No dependence of the average particle size on the rate of mixing has been obtained for the PP/PS (75/25) bl ends. On the other hand, decrease of the average particle size with in creasing rate of mixing has been found for the PP/PS (95/5) blend. The se results are discussed as a consequence of the competition between t he breakup and coalescence of the dispersed particles. (C) 1996 John W iley & Sons, Inc.