BLENDS OF POLY(STYRENE-RAN-2,4-DINITROSTYRENE) WITH POLY(VINYL METHYL-ETHER) AND POLY(2,6-DIMETHYL-1,4-PHENYLENE OXIDE)

Phase boundaries and lower critical solution temperatures for blends o f random styrene-dinitrostyrene copolymers with poly(vinyl methyl ethe r) and with poly(2,6-dimethyl-1,4-phenylene oxide) have been establish ed. From an analysis of phase behaviour in terms of the overall blend interaction energy density the relevant segmental interaction energy d ensities have been evaluated and these have been compared with the cor responding energy densities for mononitrated copolymers. It was conclu ded that nitro group substitution has an adverse effect on mixing with poly(vinyl methyl ether) despite its electron withdrawing capabilitie s, and causes a similar effect in poly(2,6-dimethyl-1,4-phenylene oxid e) mixtures for primarily structural reasons. (C) 1997 Elsevier Scienc e Ltd.