Synergism in Mechanical Properties of Polymer/Polymer Blends

Abstract

A wide range of physical and mechanical properties can be achieved in polymer/polymer blends by variation of such features as the molecular structure of the components, blend composition, morphology, and processing conditions [1–6]. If the two components of a binary blend are completely miscible at the molecular level, only a single phase will be present, and the glass transition temperature T _g of the blend will lie between the respective T _g's of the two components. This occurs, for example, in blends of polystyrene (PS) and poly (2, 6 dimethyl phenylene oxide) (PPO), for which the blend T _g varies linearly with composition over the entire range [7]. The properties of such single-phase blends are reported to fall between those of the components and not to differ appreciably from values expected based on the simple rule of mixtures [2, 8]. On the other hand, if the two components of the blend are completely immiscible, two distinct phases will be present, each of which will have its own T _g that is uninfluenced by the presence of the other phase.