Compatibilization

Thermodynamically, two polymers are fully miscible when the mixture's Gibbs free energy is negative, and the interfacial tension between the components is nearly zero, leading to a homogeneous, single-phase product. In practice, most polymers are largely immiscible, meaning their entropy is very low, and their interactions are strong. As a result, the blend often exhibits weak characteristics and poor mechanical performance.

In polymer chemistry, compatibilization is the addition of a substance to an immiscible blend of polymers that will increase their stability. Compatibilizing the system will make a more stable and better blended phase morphology by creating interactions between the two previously immiscible polymers. Not only does this enhance the mechanical properties of the blend, but it often yields properties that are generally not attainable in either single pure component.