Vjera Kurešević

Miscibility in blends of sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) with homopolymers of halogen-substituted styrene derivatives

Abstract Miscibility and phase behaviour in blends of poly(p-fluorostyrene) (PpFSt), poly(o-fluorostyrene) (PoFSt), poly(p-chlorostyrene) (PpClSt), poly(o-chlorostyrene) (PoClSt), poly(p-bromostyrene) (PpBrSt) and poly(o-bromostyrene) (PoBrSt) with partially sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) copolymers [i.e. systems of the type ( A ) n 1 ( C 1− y D y ) n 2 have been studied by d.s.c. as a function of temperature and degree of sulfonylation. For all the para-substituted styrene polymers/SPPO blends studied, limited miscibility regimes are found. A miscibility regime is also found for PoFSt/SPPO blends. However, PoClSt and PoBrSt are not miscible with any SPPO. Using the mean-field approach, we have calculated all the pertinent segmental interaction parameters for these blends. In several systems, certain blends have been found to exhibit lower critical solution temperature behaviour.

Miscibility and phase behaviour in poly(2,6-dimethyl-1,4-phenylene oxide) and poly(fluorostyrene-co-bromostyrene) blends

Abstract Copolymers of ortho(para) fluorostyrene and ortho(para) bromostyrene with a range of copolymer compositions were prepared by free radical polymerization in toluene solution using azobis(isobutyronitrile). The miscibility and phase behaviour of these copolymers in blends with poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) have been studied by differential scanning calorimetry. Of the four possible copolymer systems, miscibility was observed only for PPO/poly( o -fluorostyrene-co- p -bromostyrene) blends in which the copolymer contains between 11 and 73 mol% p -bromostyrene. High temperature phase separation in the miscible blends is a function of copolymer composition and of the thermal history. The results can be explained on the basis of the mean field theory of phase behaviour for homopolymer-copolymer systems.

Miscibility in blends of phenylsulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) and poly(p-fluorostyrene-co-o-fluorostyrene)

Abstract Miscibility and phase separation in blends of random copolymers of p -fluorostyrene and o -fluorostyrene [P( p FSt- co - o FSt)] with phenylsulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) copolymers in which the degree of sulfonylation ranges from 4 to 92 mol% have been studied by differential scanning calorimetry (d.s.c.) at temperatures up to 320°C. It was found that miscibility depends on isomeric composition, the degree of sulfonylation, and temperature. Certain blends exhibit lower critical solution temperature ( LCST ) behaviour.

Miscibility behaviour of sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) copolymers in the blends with poly(styrene-co-maleic anhydride) and with poly(α-methylstyrene-co-maleic anhydride)

SummaryThe miscibility behaviour of sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) of the different degree of sulfonylation blended with poly(styrene-co-maleic anhydride) or poly(α-methylstyrene-co-maleic anhydride) was studied. The critical degree of sulfonylation for phase separation in these blends was found to be 55 mole % and 66 mole %, respectively. The miscibility behaviour was analyzed on the basis of the mean field treatment and studied by DSC.

Alternating copolymerization of phenylvinyl sec-butyl ether and maleic anhydride

SummaryThe reactivity ratios k1c/k1c and k2c/k21 in the copolymerization of phenylvinyl sec-butyl ether (M2) and maleic anhydride (M1) were calculated by applying the generalized model described by Shirota and coworkers. It was found that under the experimental conditions applied in our work, the copolymerization proceeds predominantly through the participation of charge-transfer complex monomers.