Synthesis of a novel poly(binaphthylene ether) containing trifluoromethyl groups with a low dielectric constant

The synthesis of poly(2, 6-dihydroxy-napthalene) (PDHN) by catalytic oxidative coupling polymerization in which the optically estimated ε of the polymer was only 2.56 despite a large number of hydroxyl group on its backbone was reported. A naphthalene ring is suitable to increase the thermal stability of polymers due to its high chemical bond energy but is not good for decreasing the ε value because of its high molar polarization. The thermal properties of the polymers were examined by thermal gravimetry (TG) and differential scanning calorimetry (DSC) which showed 5% weight loss temperature at 530 °C and glass transition temperature at 230 °C.The polymer has the low refractive index of 1.582, low dielectric constant of 2.70, and low tan δ of 0.0025 at 20 GHz. The results show that polymer had high thermal stability and good film processability.