Structural designs and synthesis of co-polycarbonates with cyclohexyl and fluorene structures: Low-dielectric constant, high solubility, and superior mechanical properties

Abstract

The rapid developments of high-speed communication and large-scale integrated circuits have accelerated the research for insulating dielectric materials with low dielectric constant, low dielectric loss, and good mechanical properties. In this study, a series of polycarbonate resins containing cyclohexyl and fluorene structures are synthesized by melt transesterification, which is low dielectric, highly thermally resistant, and soluble. The effects of fluorene structure contents on the properties of a co-polycarbonate resin were studied systematically. The results showed that the non-polar fluorene group could reduce the molecular polarization of co-polycarbonate, resulting in low permittivity of co-polycarbonate are 2.41–2.71@1 MHz. In addition, the resin has excellent solubility and can be dissolved in NMP, CH₂Cl₂, THF, and other solvents at room temperature. Furthermore, the co-polycarbonate resins also exhibit superior heat resistance with glass transition temperature (Tg) of 160.6–173.1 °C as well as admirable mechanical properties with a tensile strength of 50.54–70.72 MPa. This makes it a promising candidate for high-speed communications and large-scale integrated circuits.