Addition of Reactive Polymer

If both blend components are nomeactive, it is necessary to add two reactive polymers which provide - after reaction at the interface - an effective compatibilizer. Thus, the interfacial adhesion in PP/PE blends was enhanced by the addition of PP-g-MA and poly(ethen-co-vinylalcohol) [152] or in PP/PS blends using PP carrying oxazoline groups and carboxyl-terminated PS [153]. 

Although the addition of a reactive polymer represents a major route for the compatibilization of immiscible blends on an industrial level, the exact mechanism and kinetics of the interfacial reactions remain uncertain. The reasons for this are the different reaction rates for the same functional groups on different polymers, and the effects of flow in a mixing device which can significantly accelerate the interfacial reaction, most likely due to convection as well as to the creation of a fresh interface [154]. 

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