The influence of different length of symmetrical alkyl side chains on the dielectric constant of soluble poly(aryl ether ketone) copolymers

A series of novel amorphous poly(aryl ether ketone) random copolymers containing rigid bulky pendant adamantyl groups and different length symmetrical alkyl side chains were synthesized and characterized. The chemical structures of the copolymers were confirmed by Fourier transform infrared and proton nuclear magnetic resonance spectroscopies. The influence of different length of symmetrical alkyl side chains on the dielectric constant, thermal property, mechanical property, and water uptake was investigated. The result shows that the dielectric constants (κ) of the copolymer films (κ = 2.72–2.90 at 1 MHz) are remarkably lower than commercial poly(ether ether ketone) (κ = 3.27 at 1 MHz), and with the increasing length of symmetrical alkyl side chains of the copolymers, the dielectric constants of the copolymers decrease. The flexibility of the copolymer films exhibits a positive trend as the length of symmetrical alkyl side chains increases. Simultaneously, the copolymers maintain good solubility, low water uptakes, and excellent thermal and mechanical properties.