A 3-D nanostructure polyhedral oligomeric silsesquioxane as a (co)-crosslinker of an epoxy resin

Abstract

Epoxy resins have outstanding properties with variety uses especially in high performance engineering applications. However, high degree of crosslinking density makes them rigid and brittle. Many attempts have been used to improve mechanical properties, especially toughness. In the current work, synergistic properties of using the polyhedral oligomeric silsesquioxane nanostructure (POSS) and polyether amine chains has been used to improve toughness and mechanical properties especially modulus by using the synthesized structure as co-curing agent in epoxy resin. The characteristic analysis showed that the structure of the synthesized molecule is a POSS core with four polyether amine chains and four glycidyloxy propyl chains attached to the siloxane cage. The results indicated that using the synthesized structure (GA-POSS) as co-curing agent has two effects: it acted like a reinforcing agent and improve glass transition temperature, toughness and Young’s modulus. Also, it increased distance between crosslinks which led to increase of tan δ and elongation at break. However, these effects did not observed when this nano-molecule worked as cross linker or when the POSS structure doesn’t have soft long chains because just in the case of using GA-POSS as co-curing agent hard-soft-hard state is formed which leads to high mechanical and toughness properties, simultaneously.