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 polyamidoaminesilica
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 glasstransition
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.