Comb-like ionomers from sustainable resources: Copolymers of itaconic anhydride-co-stearyl methacrylate

Comb-like random copolymers of itaconic anhydride (ITA) and stearyl methacrylate (SM) copolymers were synthesized by free-radical polymerization. Both monomers are derived from natural and renewable resources. Ionomers (Na, Ca or Zn carboxylates) were prepared by partial neutralization of the copolymers. The incorporation of the ionic groups decreased the melting point, which was lower than the glass transition temperature (Tg) and crystallinity of the SM side-chains and increased the Tg of the backbone by 20–25 °C. Above Tg, the parent copolymer was a viscoelastic liquid, but the introduction of the ionic groups changed the properties to that of an elastic solid due to the physical crosslinks formed by intermolecular interactions of the ionic dipoles.