Modelling of Synthetic Binders

The first attempt to predict the rheological properties of the synthetic binders was performed according to the following equation  

Where r j is the complex viscosity predicted for the synthetic binder, r p and rij, are the complex viscosities for the pure components (oil, resin and polymer respectively), and Cl, C2, C3 and C4 are constant parameters. In addition, constant parameters are dependent upon the concentration of the pure components as follows  

Where Xq, Xr, Xop2o and Xop4o are the weight fractions of the oil, resin and polymer in the synthetic binders (made from binary oil-polymer blends containing 20 and 40% of polymer, respectively). 

The development of the fitting parameters with the concentration shows a high dependence on the type of binary oil-polymer blends. Parameter C3 can only be fitted to 2 different linear models (Equations 10.4 and 10.5), one for each oil-polymer ratio, because synthetic binders are strongly dependent on the polymeric phase at flow temperatures. 

In order to confirm this observation, a new fitting was realised taking into account the oil-polymer ratio for each synthetic binder. The following equation was employed 

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