Modification of tannin based rigid foams using oligomers of a hyperbranched poly(amine-ester).

Tannin-based rigid foam is an excellent alternative for other commercial foams due to price advantage, excellent fire resistance and low thermal conductivity. However, expanding its usability is restricted by its corresponding inferior mechanical properties. In the current work, we proposed a novel modification method which markedly improved its mechanical properties with respect to other approaches. The novel modification depends on boosting the foam network structure by adding oligomeric precursors (hydroxyl-terminated) of a hyperbranched poly(amine-ester) together with glutaraldehyde (crosslinker) as parts of the formulation where it was found that the compressive strength elevated remarkably and reached maximum of 37 % with respect to conventional formulation in absence of these additives or in presence of either of these additives alone. The novel modification method may show promise to obtain such materials for lower price under optimized conditions with respect to other reported modifiers due to the huge functionality of a hyperbranched polymer. [ABSTRACT FROM AUTHOR]