compatibilization

Compatibilization is a strategy in polymer science to improve the compatibility of immiscible polymer blends by introducing a compatibilizer. The compatibilizer is typically a polymer or particle that localizes at the interface between dissimilar polymers, reducing interfacial tension and promoting finer, more uniform phase dispersion. This can lead to improved mechanical properties, impact resistance, and processability compared with the ungelled blend.

Mechanisms include interfacial localization of block or graft copolymers whose segments are miscible with each phase, thereby lowering interfacial energy and enhancing stress transfer. In reactive compatibilization, functional groups on the compatibilizer or the polymers react during melt processing to form covalent bonds across the interface, creating a chemically linked interphase. Nanoparticles or nanofillers can also act as compatibilizers by providing a three-dimensional network that stabilizes the morphology.

Common types of compatibilizers include block copolymers such as polystyrene-block-polybutadiene-block-polystyrene in polystyrene/polybutadiene blends; graft copolymers with reactive groups (for example, maleic anhydride grafted polyolefins) used to compatibilize polyolefin blends with polyamides or polyesters; and various in situ forming copolymers via reactive extrusion.

Applications span packaging, automotive parts, and electronics, where increased tensile strength, impact resistance, and barrier properties are desirable. Processing requires optimization of blend composition, ratio of compatibilizer, and processing conditions to balance morphology, viscosity, and clarity where relevant.