The effects of chemical structure on the dielectric properties of polyetherimide and nanocomposites

Low dielectric constant polyetherimides have been synthesized by incorporating a bisphenol A dianhydride, BPADA, and 2,7-bis(4-aminophenoxy) naphthalene (BAPN), a phenylene ether diamine. The flexible ether and larger planar naphthalene structure of BAPN led to more spacing between polymer molecules, resulting in less efficient chain packing and an increase in the free volume, thus decreasing the dielectric constant. New PEI/silica hybrid nanocomposites were prepared from this novel polyetherimide via sol-gel process. The dielectric constants were further decreased with the incorporation of silica. These synthesized PEI and nanocomposites have high thermal stability and good mechanical properties.