MISCIBILITY AND PHASE-SEPARATION STUDY OF BLENDS OF RANDOM COPOLYMERSOF O(PARA)-FLUOROSTYRENE-CO-ORTHO(PARA)-BROMOSTYRENE] WITH PHENYLSULPHONYLATED POLY(2,6-DIMETHYL-1,4PHENYLENE OXIDE) COPOLYMERS BY THERMAL METHODS

The miscibility and phase separation behaviour of random copolymer ble nds of poly ho(para)-fluorostyrene-co-ortho(para)bromostyrene] (poly[o (p)FSt-co-o(p)BrSt]) with partially sulphonylated poly(2,6-dimethyl-1, 4-phenylene oxide) (SPPO) copolymers has been studied by differential scanning calorimetry (DSC) at temperatures up to 573 K. It was found t hat these systems exhibited miscibility-immiscibility behaviour which was dependent on the halogen atom, its position on the benzene ring an d predominantly on the degree of sulphonylation. Copolymers of oFSt an d pFSt with pBrSt exhibited miscibility with SPPO with higher degree o f sulphonylation than copolymers containing oBrSt. The miscibility beh aviour was analysed on the basis of the mean-field theory in terms of the individual segmental interaction parameters.