Due to differences in their chemical structures and physical properties, polymer blends, which are made up of two or more distinct polymers, sometimes display restricted compatibility. The use of compatibilizers, often referred to as compatibilizing agents or reactive modifiers, is essential for enhancing the compatibility of polymer blends. One of the main ways that compatibilizers improve compatibility is by encouraging interfacial adhesion between the immiscible polymers in the blend. In order to strengthen interfacial contacts and lower interfacial tension, compatibilizers have functional groups that can interact with both polymers. Phase separation is reduced by the enhanced adhesion, which also improves the blend’s overall compatibility. Reactive Functional Groups: Numerous compatibilizers have reactive functional groups that can interact chemically with the blend’s polymers. By allowing covalent connections to develop between the incompatible polymers, these reactive groups help to build a network that increases compatibility. Grafting, crosslinking, and copolymerization are examples of functionalization reactions that improve intermolecular interactions and produce more homogeneous mix structures. Control of Morphology: By adjusting the size, distribution, and dispersion of the dispersed phase within the continuous phase, compatibilizers can modify the morphology of polymer blends. Compatibilizers encourage a finer and more uniform morphology, which leads to increased blend compatibility and mechanical properties. They do this by lowering the size of scattered domains or by forming interfacial layers rich in compatibilizers. Branching and Chain Extension: Some compatibilizers have the capacity to add branching structures or prolong the polymer chains, which can improve compatibility in polymer blends. Chain extension improves interdiffusion and lessens phase separation by increasing molecular entanglement between the polymers. Additionally, branching can change the structure of the polymer chain, lowering the mobility of the polymer segments and increasing compatibility.     Energy Dissipation and Toughening: Some compatibilizers have methods for dissipating energy, such as rubbery domains or segments made of elastomers. These domains have the ability to absorb and release energy during deformation, increasing the blend’s toughness and impact resistance. Phase separation’s detrimental effects are lessened and the blend’s resistance to fracture propagation is improved by compatibilizers with energy dissipation capabilities. Influence on Processing Conditions: Compatibilizers can also have an impact on how polymer blends are processed. They can alter the melt’s viscosity, flexibility, and stability, making it easier to process and combine immiscible polymers during the melting process. Compatibilizers with enhanced processing properties facilitate effective melt mixing, fostering greater interfacial interactions and dispersion amongst blend constituents. Compatibilizers are essential for increasing the compatibility of polymer blends by encouraging reactive interactions, lengthening polymer chains, regulating morphology, dissipating energy, and altering processing conditions. Manufacturers can create polymer blends with higher mechanical qualities, increased heat stability, and more application options by using compatibilizers. Understanding the processes through which compatibilizers increase compatibility aids in the logical design and selection of these additives, opening the door for the creation of innovative polymer blends in a variety of industries.