polyolefinegrafted

Polyolefinegrafted (often written polyolefin-grafted) describes polyolefin polymers that have polar or reactive functional groups chemically attached to an otherwise nonpolar polyethylene or polypropylene backbone. Grafting is used to introduce compatibility, adhesion and reactivity to polyolefins, which inherently lack functional sites for bonding with fillers, polar polymers or coatings. Common grafting comonomers include maleic anhydride, acrylic acid, glycidyl methacrylate and various vinyl monomers.

Grafting is typically performed by reactive processing methods such as melt grafting during extrusion with peroxides or other radical initiators, solution grafting, or radiation-induced grafting. Reactive extrusion is widely employed industrially because it combines mixing, reaction and devolatilization in a continuous step. The grafting reaction must be controlled to limit chain scission, crosslinking and homopolymer formation, which can affect molecular weight and mechanical properties.

Characterization methods include FTIR and NMR spectroscopy to confirm functional groups, titration for grafting level, gel permeation chromatography for molecular weight changes, and thermal analysis and rheology for property assessment. Polyolefin-grafted materials are used as compatibilizers in polymer blends, coupling agents in fiber-reinforced composites, adhesion promoters in coatings and adhesives, and impact modifiers. Advantages include improved interfacial bonding and expanded application range; limitations include potential polymer degradation during grafting and the need to balance graft density with retention of bulk polyolefin properties.