Curing behavior and dielectric properties of amino-functionalized polyhedral oligomeric silsesquioxane/cyanate ester resin hybrids

In order to improve the dielectric and overall properties of cyanate ester (CE) resin, octa(aminopropyl)silsesquioxane (POSS-NH₂) was used to modify CE. A series of POSS-NH₂/CE hybrids containing different contents of polyhedral oligomeric silsesquioxane (POSS) were elaborated by melt casting and then curing. The curing kinetics and reaction mechanisms of the resin systems were studied using Fourier-transform infrared (FT-IR). Dielectric properties, thermal stability, and hot/wet resistance of the hybrids have been investigated. FT-IR results show that both temperature and POSS content may influence the curing reaction of CE. POSS-NH₂ mainly displays the catalytic effect at higher temperature (220°C). Dielectric results indicate that NC1 containing 1 wt% of POSS displays not only the lowest dielectric constant but also the lowest dielectric loss. The increase in POSS content leads to significant increase in glass transition temperature (T_g) at lower POSS content (≤5 wt%). However, further increase in POSS content (>5 wt%) does not lead to great increase in T_g. Besides, all the POSS-NH₂/CE hybrids show lower water absorption than that of CE.