Novel transparent poly(arylene ether nitrile) with low dielectric constant: Synthesis and characterization

The novel poly (arylene ether nitrile) copolymers P-HAD and P-PAD containing pendant aliphatic ring and -CF₃ group were synthesized by 4, 4′-cyclohexane-1, 1′-diyldiphenol (CHDP) or 4, 4′-cyclopentane-1, 1′-diyldiphenol (CPDP), 4, 4′-(hexafluoroisopropylidene) diphenol and 2, 6-dichlorobenzonitrile (DCBN) through nucleophilic polycondensation using NMP as the solvent in the work. The copolymers owned the inherent viscosities of 0.269-0.868 dL g^-1. They exhibited good thermal property, the glass transition temperatures (T_g) were 169.3-173.2°C, the weight-loss temperatures (T_5%) were 464.2-470.2°C, and the heat resistance indexs (HRI) were 238.6-248.6°C. The copolymers’ films had good tensile strengths of 62.9-75.1 MPa. Because of the introduction of -CF₃ unit, the solubility, dielectric property and optical property were improved well. The copolymers could be dissolved in some solutions at room temperature, such as NMP, DMF, CH₂Cl₂ and CHCl₃, they can be processed by solution method. They had good dielectric property, the dielectric constants were 4.3-4.6 at about 1000 KHz. Additionally, the optical transmittance of these two copolymers were 75.2-76.3% at 450 nm, which have potential to be applied as the heat-resistant optical films in the 5G area or electronic field.