Polymer blends are typically described by coarse, unstable phase morphologies; this results in poor mechanical properties.
Compatibilizing the system will make a more stable and better blended phase morphology by creating interactions between the two previously immiscible polymers.
In turn, these phase separated particles will not be as inclined to consolidate and grow because the interfacial tension is now much lower.
They are able to act as good compatibilizing agents for blends of polypropylene and low density polyethylene.
This is because cocrystallization also factors into this case, and the longer ethylene sequences will retain some residual crystallinity.
Copolymers are formed when the proper functional groups in each component of the immiscible blend interact in the compatibilization process.