MISCIBILITY OF POLYSTYRENE (PS) POLYPHENYLSILSESQUIOXANE (PPSQ) BLENDS/

PS/PPSQ blends with different compositions were prepared by two method s: (1) casting film of PS/PPSQ from the solution of two polymers, and (2) PS/PPSQ blends by in situ polymerization. After studying by solid- state NMR, PS and PPSQ in the casting films are miscible on the scale of several thousand nanometers. Miscibility of PS/PPSQ blends obtained by the second approach was investigated by DMA, SEM, x-ray energy spe ctrometer, x-ray diffraction, and fluorescence techniques. Only one gl ass transition temperature could be observed in their DMA curves. Ther e are two phases observable in their SEM micrographs. X-ray diffractio n patterns and fluorescence excited spectra of this blend indicate tha t there is some interaction between molecules of PS and PPSQ in both t he continuous phase and dispersed phase. PS and PPSQ in the in situ bl ends are partially miscible when the percentage of PPSQ is not more th an 10%. (C) 1996 John Wiley & Sons, Inc.