Abstract
In this study, the cage polysilsesquioxane, Isocyanatopropyldimethyl- silyl-Isobutyl-POSS (IPI-POSS) was reacted with epoxy resin to form silicon containing modified epoxy (IPEP). Furthermore, various contents of IPEP were added to DGEBA epoxy resin to fabricate epoxy nanocomposites. It is anticipated that the nanocomposites prepared will exhibit excellent thermal stability and flame retardance. FTIR, ATR and 29Si Solid-state NMR were used to characterize the reactivity and the structure of IPEP and nanocomposites. SEM, TEM, AFM and XRD were used to study the morphology of the nanocomposites. DSC, TGA, DMA, LOI were utilized to analyze thermal property of nanocomposites. Moreover, the kinetics of curing and thermal degradation were studied by Ozawa and Kissinger method. The XRD patterns show that all nanocomposites were amorphous.The SEM microphotographs indicated that the nanocomposites possess good compatibility and no aggregation was observed. The TEM microphotographs showed that the POSS particle was about 2~5 nm. The AFM microphotographs exhibited that the surface of the nanocomposite was smooth. Incorporation of IPEP into epoxy resin can enhance the thermal stability of the nanocomposites. The glass transition temperature of the nanocomposite material increased from 118oC to 172oC, char yield increased from 14.39 % to 21.41 %, IPDT increased from 604oC to 778oC. Furthermore, the nanocomposites also possess excellent flame retardance (LOI 28), low rate of degradation and high activation energy of degradation. The activation energy of degradation increased with the increasing of IPEP content. The storage moduli and hardness of nanocomposites also increased with the increasing of IPEP content. The storage moduli of nanocomposites were increased from 41.17 MPa to 88.84 MPa. The hardness of nanocomposites was increased from 34.4 to 43.5.