Cycloaliphatic epoxy-based hybrid nanocomposites reinforced with POSS or nanosilica for improved environmental stability in low Earth orbit

The purpose of this study is to demonstrate the properties of novel nanocomposites, based on cycloaliphatic epoxy resin additionally reinforced with silicon-containing nanostructures (mono- or octa-functional POSS or nanosilica). The changes in properties are discussed for the varied combinations of cycloaliphatic epoxy with a curing agent (cycloaliphatic amine or anhydride) and the nanomodifier. The influence of modification on thermal stability, curing behaviour, morphology, surface chemistry, and topography were studied with TGA, DSC, ATR-FTIR, XPS and LCM. The results show that when POSS and/or nanosilica are incorporated to the cycloaliphatic matrix they influence curing behaviour and glass transition temperatures (Tg), where mono-POSS increases Tg and octa-POSS decreases it with respect to nanosilica. Mono-POSS produces silicon-rich surfaces but tends to agglomerate and increase surface roughness. Octa-POSS and nanosilica penetrate the polymer matrix more deeply and disperse more easily. From the selected modifiers, octa-POSS shows the highest thermal stability.