This work is part of a comprehensive study on the design of synthetic binders. The overall objective of the whole research was to study the influence that the nature of each binder constituent, its mechanical and thermodynamic properties, binder composition and processing conditions exert on the microstructure and the theological properties of the final product. Particularly, this work presents and correlates thermodynamic and theological results of binary oil-resin blends, with the aim of estimating its viscous behaviour, in the whole range of in-service and processing temperatures, by means of temperature-dependent models. The results obtained give some insight in the relationship between phase microstructure and mechanical properties of different binary oil-resin blends. (c) 2005 Elsevier B.V. All rights reserved.