Determination of transition points and thermodynamic interaction parameters of poly(2,6-dimethyl-1,4-phenylene oxide)

The specific retention volumes V g0 of n-butyl acetate, isobutyl acetate, isoamyl acetate, n-undecane, n-dodecane, n-tridecane, ethyl benzene, n-propyl benzene, isopropyl benzene and chloro benzene on poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) were obtained by inverse gas chromatography. Below glass transition temperature, two secondary transition points of PPO which occur at 90 and 130°C were observed from the retention diagrams of n-butyl acetate, isobutyl acetate and isoamyl acetate.Weight fraction activity coefficient at infinite dilution Ω 1∞, Flory–Huggins polymer–solvent interaction parameter χ 12∞, hard core polymer–solvent interaction parameter χ 12* and effective exchange energy parameter X eff were determined from the experimental V g0 of studied solvents on PPO at temperatures above 220°C by inverse gas chromatography.