Graftkopolymere

Graftkopolymere are macromolecules in which side chains of one polymer are covalently attached to the main chain of another polymer, producing a grafted or comb-like architecture. They are a major class of graft polymers and can be described by the nature of the backbone and grafts as well as their grafting density and side-chain length.

Synthetic routes to graftkopolymere include grafting-from, where polymerization proceeds from reactive sites along the backbone; grafting-onto, where preformed side chains are attached to the backbone; and grafting-through, in which macromonomers bearing polymerizable units are incorporated into the growing material. The resulting architectures range from sparse grafts to densely grafted brushes, with variations in side-chain composition.

Key properties arise from architectural parameters: high functionality, tunable solubility and rheology, enhanced compatibility in immiscible polymer blends, and adjustable mechanical and thermal behavior. They are widely used as compatibilizers in polymer blends, viscosity modifiers, adhesives, coatings, and, in some cases, as elastomeric networks when paired with flexible backbones. Common examples include polypropylene backbones grafted with polar styrene derivatives or with maleic anhydride to improve adhesion and compatibility with polar polymers.

Characterization typically employs NMR, FTIR, size-exclusion chromatography, differential scanning calorimetry, and rheological measurements to assess graft density, side-chain length, and molecular weight distribution.

Historically, the concept of graft copolymers emerged in the mid-20th century and has since evolved toward more controlled grafting techniques and functional grafts for targeted applications.