Flame retardancy and thermal stability of organic-inorganic hybrid resins based on polyhedral oligomeric silsesquioxanes and montmorillonite clay

Organic-inorganic hybrids were prepared by incorporation of two polyhedral oligomeric silsesquioxanes, trisilanolisobutyl POSS (TSP) and isobutylAluminum POMS (AlP), and an organoclay (OC), in an epoxyamine system. Differential scanning calorimetry revealed the great catalytic power of AlP. OC also showed catalytic power, but to a lesser extent. The storage modulus increased with lower POSS contents, due to the nanoreinforcing effect of POSS core. At higher concentration, the modulus strongly decreases due to POSS aggregation. The glass transition temperature was barely affected by the POSS, whereas OC addition decreased it. FOSS and OC supplied greater thermal stability in high temperature regions, and the char residue increased with filler concentration because silicon species are formed. POSS addition improved the flame retardancy because of a multilayered carbonaceous silicate structure formation. The presence of metal atoms in AlP composites might contribute to stabilization through secondary chemical reactions. (C) 2014 Elsevier Ltd. All rights reserved.