ABSTRACT
A large number of experimental methods have been used to investigate the miscibility in polymer blends. The immediate consequence of this strong temperature dependence of relaxation time distribution is that the technique of master-curve construction, which is commonly used to describe the relaxation behavior of pure polymers, is no longer valid. A negative volume of mixing has been observed for many polymer–polymer systems as a result of specific interactions. The segmental motion of polymer chains in the amorphous bulk phase can be described in terms of correlated conformational transitions that arise from both intra- and intermolecular constraints due to the connectivity of the monomer units. The design, selection, and performance of polymer blends crucially depends on our ability to predict and control the phase behavior of selected polymer–polymer pairs. A pronounced asymmetry of the relaxation spectrum with a low-frequency tail appears to be a common feature of many polymer blends.
