What exactly is a compatibilizer? What is its core function?

A compatibilizer, also known as a compatibilizing agent or macromolecular coupling agent, is a functional additive used to improve the interfacial bonding between two or more inherently incompatible materials. Its molecular structure typically contains segments that can interact (through physical entanglement or chemical reactions) with different components in the blend system, acting like an "intermediary" or "bridge" to effectively reduce interfacial tension, enhance dispersion uniformity, and improve interfacial adhesion. The core function is to address the "1+1<2" challenge in material blending. By optimizing the interface, the mechanical properties (such as tensile strength and impact toughness), processing rheology, and long-term stability of the final composite material are significantly enhanced.