Interphase and Compatibilization by Addition of a Compatibilizer

Abstract

Polymer blends are mixtures of at least two macromolecular species, polymers and/or copolymers. For practical reasons, the name blend is given to a system only when the minor component content exceeds 2 wt%. Depending on the sign of the free energy of mixing, blends are either miscible or immiscible. In a general sense, the polymer/polymer miscibility does not exist — it is always limited to a “miscibility window”, a range of independent variables, such as composition, molecular weight, temperature, pressure, etc. More than 1600 of these “miscibility windows” have been identifi ed for two, three or four components’ blends. The immiscibility dominates the fi eld [Utracki, 1989]. For more details on the thermodynamics of mixing and phase diagrams, the reader is referred to Chapter 2. Thermodynamics of Polymer Blends in this volume.