THEORY OF STATIC SCATTERING FROM POLYMER MIXTURES - THE CASE OF POLYSTYRENE POLYDIMETHYLSILOXANE POLY(METHYL METHACRYLATE) TOLUENE

The static scattering properties of four-component polymer mixtures ar e examined starting from the general equation extending the random pha se approximation to multicomponent systems first proposed by Benoit. T he results are compared with the light scattering data reported recent ly by Strazielle and coworkers for polystyrene/polydimethylsiloxane/po ly(methyl methacrylate)/toluene mixtures. The present formalism provid es a more rigorous treatment of these data, and a good agreement is ob tained without adjustable parameters. This method provides a definitio n of the apparent interaction parameter used by Strazielle et al. and describes its correlation with various relevant quantities characteriz ing the mixture. It predicts in particular the variation of this param eter with the concentration of poly(methyl methacrylate), which was no t possible in the earlier work. Various other important properties of the mixture are investigated such as the critical concentration for ph ase separation and the apparent radius of gyration.