High performance multi-functional cyanate ester oligomer-based network and epoxy-POSS containing nanocomposites: Structure, dynamics, and properties

The aim of this research was the detailed analysis and estimation of CER oligomer-based nanocomposites for applications under extreme high temperature conditions. Thermostable nanocomposites based on cross-linked cyanate ester resin (CER), derived from PRIMASET PT-30 multi-functional oligomer and doped by 0.025wt% to 10wt% epoxycyclohexyl-functionalized polyhedral oligomeric silsesquioxane (ECH-POSS) nanoparticles, were synthesized and characterized using TEM, mid-, and far-IR spectroscopy, and by DMA, DSC, CRS, and TGA techniques. At nanoparticles contents less than 1wt%, basically their molecular level dispersion in the matrix is suggested, whereas their clusters of about 20 to 30 nm in diameter were observed at 2wt% and 10wt% ECH-POSS. In correlation with the results of structural analysis, the ambivalent influence of the nanoparticles, depending on their content, on the dynamics and properties of nanocomposites was revealed. The "constrained dynamics" effects caused by post-curing and covalent embedding ECH-POSS units into the matrix were registered by DMA, far-IR spectroscopy and CRS. Highly cooperative glass transition with T-g approximate to 400 degrees C (DMA, 1 Hz) was observed, and at the limit total suppression of glass transition could be achieved. The obvious superiority of the studied nanocomposites over the CER nanocomposites synthesized from monomeric dicyanate ester of bisphenols, especially at high temperatures, was shown.