Role of POSS as Coupling Agent for DGEBA/GF Reinforced Nanocomposites

In the present study a DGEBA based epoxy resin and glass fiber (GF) [70:30] combination was reinforced with different weight percentages (0.5, 1.0 and 1.5 wt%) of POSS (polyhedral oligomeric silsesquioxane) and cured with polyamidoimidazoline curing agent (Aradur 140) at room temperature. The amine functionalized POSS was synthesized via an ONPS (octa(nitrophenyl)silsesquioxane) intermediate. The structural evidence of POSS was confirmed by FTIR and ¹H NMR spectroscopic techniques. Varying weight percentages of amine functionalized POSS were incorporated into DGEBA/GF to increase the thermal, thermo-mechanical and mechanical and dielectric properties of DGEBA/GF epoxy nanocomposites, which are investigated by means of dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA) and impedance analyzer. The surface roughness behavior of DGEBA, DGEBA/GF composite and DGEBA/GF/POSS epoxy nanocomposites was analyzed by scanning electron microscopy (SEM). The obtained results indicate that enhancement in thermal and thermo-mechanical behaviour of DGEBA/GF was achieved by means of optimum addition of 1.5 wt% of POSS nanoreinforcement, which prevented phase segregation between GF and DGEBA epoxy resin, leading to a significant improvement in mechanical, thermal, thermo-mechanical and dielectric properties in comparison with those of DGEBA/GF composite and neat DGEBA epoxy matrices.