A novel ultra low-k nanocomposites of benzoxazinyl modified polyhedral oligomeric silsesquioxane and cyanate ester

Benzoxazinyl modified polyhedral oligomeric silsesquioxane (BZPOSS) is successfully synthesized and used to prepare nanocomposites with bisphenol A cyanate ester (BADCy). The DSC results showed that the curing peak temperature of BZPOSS/BADCy blend decrease significantly from 317.1 °C to 160.3 °C, suggesting the high catalytic activity of BZPOSS to the polymerization of cyanate ester. The SEM micrographs of poly(BZPOSS/BADCy) and Silicon element distribution maps given by EDS both indicated that BZPOSS disperses evenly in BADCy. Dielectric properties tests showed that the dielectric constant can be reduced by the introduction of BZPOSS, which is attributed to the nano-pores from the cage structure of POSS. When 15 wt% BZPOSS was added, the dielectric constant decreased to 2.01 and the dielectric loss was also only 0.0070 at 1 MHz. Meanwhile, DMA and TGA result showed that the thermal stability and heat resistance of poly(BZPOSS/BADCy) at high temperature decreased with increasing BZPOSS, which is due to the change of crosslinking structure of the copolymers. The influences of the crosslinking structure and the nano-porous organic-inorganic hybrid particles on the dielectric and thermal property of poly(BZPOSS/BADCy) were also discussed.