Interaction between poly(vinyl pyridine) and poly(2,6-dimethyl-1,4-phenylene oxide): A copolymer blend miscibility study

The phase behavior of blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with random copolymers of styrene and 2-vinyl pyridine, Poly(S-co-2VP), as well as with random copolymers of styrene and 4-vinyl pyridine, Poly(S-co-4VP), has been investigated in order to estimate the values of the Flory-Huggins parameters χPPO,2VP and χPPO,4VP between PPO and 2-vinyl pyridine, resp. 4-vinyl pyridine. Using previously estimated values for the Flory-Huggins parameters 0.09<χS,2VP<0.11 and 0.30<χS,4VP<0.35, together with the literature value of χS,PPO=−0.043, the phase behavior observed as a function of the copolymer composition results in 0.11≤χPPO,2VP≤0.12 and 0.46≤χPPO,4VP≤0.48. Insight in the interaction between PPO and poly(vinyl pyridine) is of considerable interest for several nanotechnology developments, since PPO is used to improve the mechanical properties of e.g. PS-block-P4VP nanorods.