Selective Interactions in Elastomers, a Base for Compatibility and Polymer-Filler Interactions

Abstract This paper describes the determination of accurate solubility parameters for nonpolar rubbers according to a GLC-method developed by Guillet. The data obtained provide a simple but meaningful thermodynamic characterization of the contribution of microstructure units and comonomers (styrene) in polydienes. On this basis quantitative expressions are derived for δ2 -parameters of BR and SBR as a function of the vinyl and the styrene content respectively. The consequences on morphology development and miscibility are presented for blends of NR, SBR, BR and EPDM. Furthermore, it is shown for the first time that the method is able to describe the temperature dependence of the δ2 -parameter so that temperature induced phase transitions (UCST and LCST) can be predicted. On this basis morphological predictions are made on average domain size and size distribution as well as on the phase inversion region. The contribution of intermolecular interactions to flow-induced phase morphology is discussed in relation to the influence of rheological factors. An extension to polymer—filler systems is made.