Influence of diluent mobility on the plasticization of polymers

In an attempt to formulate a general picture of the influence of diluents on the physical properties of polymers without invoking specific molecular characteristics of the diluents, a systematic study has been undertaken of the mobility of both the polymer and the diluent in polymer-diluent systems, and of the resulting effects on the physical properties of these systems. In dynamic mechanical and dielectric loss studies of polymer-diluent systems, the influence of the mobility of the diluent on the background loss as well as on the loss associated with subsidiary relaxation transitions has been followed as a function of temperature and correlated with the temperature dependence of the modulus, over temperature ranges which include the low-temperature γ and β transitions. The temperature ranges of plasticization and antiplasticization have been established for bisphenol A polycarbonate and atactic polystyrene plasticized with various phthalates and chlorinated biphenyls and terphenyls, which were selected to have a wide range of glass transition temperatures and plasticizing efficiencies.