Physical-chemical Background of Compatibilisation

Regarding the structure of compatibilisers, they are generally copolymers which are formed by the bonding of at least two different monomers. The properties of 

The dissolution of polymer blends is generally modelled by the Flory-Huggins solution theory and the Gibbs free energy between the two components can be calculated as AG = AT-TAS [9-11, 16, 21-23, 32-53, 55-75]. 

As already known, a phase diagram shows the miscibility of two components. Phase diagrams describe the miscible conditions depending on the molar ratio of the two components, the temperature and the energy of the interdispersing polymer 

As mentioned previously, the interfacial tension is a key parameter in the application of compatibilisers. Generally, the interfacial tension of immiscible phases is high. The main effect of the compatibilisers is that they decrease the interfacial tension, resulting in better adhesion between the phases compatibilisers also have an effect upon the interfacial tension difference [33, 46]. 

The surface area is also a key parameter when trying to increase the compatibility of immiscible phases. Paul and Newman found that the interfacial area covered by compatibilisers is a function of 1/W, the average radius of the dispersed phase and the volume fraction of the dispersed phase [34]. Generally, the average radius of the dispersed phase decreases upon increasing the compatibiliser concentration, while the interfacial surface area covered by the compatibiliser increases, decreases or remains unchanged. 

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