ABSTRACT
The mixing of two or more polymers is an aspect of technology that lately has received special attention because blending represents a new, easy, and ef- cient method for obtaining advanced materials with special properties that are not found in individual components. In relation to polymer mixtures, the term miscible has been used to describe the multicomponent system behavior that is similar to that of a single-phase system (Krammer 1990). The term does not necessarily refer to polymers mixing at the segmental level, but it suggests that, at this level, the macroscopic properties are characteristics of a single-phase materials. By mixing at least two polymers, miscible, immiscible, or partially miscible blends can be obtained. In many cases, polymers are not miscible (i.e., compatible) because the thermodynamic parameters-namely the entropy and enthalpy of blending-are unfavorable. For this reason, studies on miscibility or on phase separation are essential. There are several methods for characterizing polymer blends, such as differential scanning calorimetry (DSC),
1.1 Introduction ......................................................................................................3 1.2 Thermodynamics of Miscible and Immiscible Polymer Blends ......................4 1.3 Effect of the Compatibilizer .............................................................................6 1.4 Miscible/Immiscible Polymer Blend Rheology .............................................. 11 1.5 Impact of Polymer Blend Rheology on the Development of
Commercial Products ..................................................................................... 16 1.6 Conclusions ..................................................................................................... 17 References ................................................................................................................ 17
dynamic mechanical thermal analysis (DMTA), dielectric measurements, cloud point measurements, and nuclear magnetic resonance spectroscopy (NMR). All of these allow the determination of polymer mixtures’ compatibility only over a certain size range (Utracki 1990).
