Organic-Inorganic Hybrid Materials with the Ability to Bind Metal Ions: Calorimetric Properties and Thermostability

Organic-inorganic hybrid materials with excellent heavy metal ions chelating properties were synthesized by covalent bonding of multifunctional polymers of polyamidoamine (PAA) type onto silica. Two series of polyamidoamine-silica hybrid materials differing in the PAA chemical structure were prepared and their thermal properties were investigated. Differential Scanning Calorimetry was used to study the effects of chain immobilization and ion chelation on the glass-transition temperature (Tg) of the polymers. The Tg of PAA-hybrid materials was elevated with respect to ungrafted PAAs. Complex formation with metal ions such as Cu⁺⁺ or Co⁺⁺ caused total suppression of Tg for both linear polymers as well as the corresponding hybrid materials. Finally, the silica particles slightly influenced the decomposition temperatures of linear polymers increasing their thermal stability.