Synthesis of Aromatic Polyamide Copolymers with Reduced Dielectric Constant

To obtain aromatic polyamides with reduced dielectric constant, a series of aromatic polyamide copolymers derived from the reaction between m-phenylenediamine to trans-1,2-cyclohexanediamine and isophthaloyl chloride were synthesized using the low-temperature solution polymerization in the presence of 2-methylpyridine. The influence of the content of trans-1,2-cyclohexanediamine on the structure and properties of aromatic copolyamides was evaluated. With increasing the content of trans-1,2-cyclohexanediamine, the inherent viscosities of copolymers decrease from 1.95 to 1.14 dL/g. The copolymer with 25 mol % of trans-1,2-cyclohexanediamine has a reduced dielectric constant er of 4.61 at 1 MHz, which is 26% lower than homopolyamide. Meanwhile, as-synthesized aromatic polyamides and copolyamides show good thermal stability and mechanical properties.