MISCIBILITY IN BLENDS OF SULFONYLATED POLY(2,6-DIMETHYL-1,4-PHENYLENEOXIDE) AND POLY(P-BROMOSTYRENE-CO-O-BROMOSTYRENE)

Miscibility in blends of random copolymers of p-bromostyrene (pBrSt) a nd o-bromostyrene (oBrSt) [P(pBrSt-co-oBrSt)] with partially sulfonyla ted poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) have been studied by differential scanning calorimetry (DSC). For an SPPO of given degree of sulfonylation, a miscibility window in terms of the isomeric compos ition of the brominated copolymer was seen; the location and width of the window was a function of sulfonylation. In general, copolymers wit h a higher content of pBrSt exhibit miscibility with SPPOs with higher degrees of sulfonylation. Upon annealing to temperatures of 280-degre es and 320-degrees-C, only small changes in the miscibility regime wer e observed. The miscibility behavior was analyzed on the basis of the mean-field theory in terms of the individual segmental interaction par ameters. (C) 1994 John Wiley & Sons, Inc.