Abstract: Methyl-polyhedral oligomeric silsesquioxanes (POSS) were blended with epoxy acrylate (EA) to prepare nanocomposites through UV-curing process. The methyl-POSS nanoparticles were added to EA by physically blending at loadings of 1wt%， 5wt%， 10wt% and 15wt%. The EA/POSS nanocomposites were studied through XRD， SEM， EDS and TGA analysis. The results showed that there are methyl-POSS crystals in samples containing high POSS mass fraction，implying the existing of phase separation in EA/POSS nanocomposites. The POSS aggregates are observed in the nanocomposites， and both the size and number of aggregates are all increased with the increasing of POSS loadings. There are also POSS molecules dispersing in the EA matrix. The nanocomposites thermal stability is improved and the degradation mechanism of EA is not affected by POSS.

Key words: epoxy acrylate, POSS, UV-curing, nanocomposites, miscibility, thermostability