CHARACTERIZATION OF THE INTERPHASE IN PPO PMMA BLENDS COMPATIBILIZED BY P(S-G-EO)/

The influence of a poly(styrene-graft-ethylene oxide) (P(S-g-EO)) copo lymer on poly(2,6-dimethyl-p-phenylene oxide)/poly(methyl methacrylate ) (PPO/PMMA) blends was studied by a number of different techniques in order to characterize the properties of the interphase. Scanning elec tron microscopy shows that the copolymer reduces the dispersed phase s ize, and dynamic mechanical spectroscopy (DMS) reveals a new micromech anical transition in the ternary blends. These effects are shown to be caused by a copolymer-rich interphase with a certain volume fraction and with its own characteristic properties. Solid-state nuclear magnet ic resonance (NMR) relaxation times indicate that the poly(ethylene ox ide) side chains of the copolymer are partially miscible with PMMA in the ternary blends, which suggests that the interphase does not only c onsist of pure copolymer.