Polymer nanocomposite coatings based on polyhedral oligosilsesquioxanes: route for industrial manufacturing and barrier properties

A route to a large variety of functionalized POSS compounds by a two-step procedure has been developed. Up-scaling to high volume industrial applications is feasible. In the first step, an amino-functionalized silane such as 3-aminopropyltriethoxy silane is converted to amino-functionalized POSS (amine-POSS) by a sol–gel process. In the second step, the amine groups of amine-POSS are converted by state-of-the-art amine chemistry. A large number of reactants including carboxylic acids, esters, anhydrides, isocyanates, carbonates, epoxides, and acrylates as well as reactants suitable for nucleophilic substitution can be applied. Conversion of an amine-POSS with hexanoic acid leads to an amide-POSS. Amine chemistry can usually be performed under mild conditions, which suppresses degradation and/or cross-linking reactions of the amine-POSS during the conversion. MALDI-TOF mass spectroscopy and dynamic light scattering (particle size: 3–6 nm) have been applied to prove the conversion of an amine-POSS to an amide-POSS. 1 H-NMR and TGA-MS prove the presence of amide-POSS and its thermal stability. Gas barrier properties of nanocomposite coatings based on functionalized POSS are characterized.