Preparation and physical properties of intrinsic low-k polyarylene ether nitrile with enhanced thermo-stability

Polyarylene ether nitrile (PEN) random copolymers were prepared from 6AF, BHPF, and 2, 6-dichlorobenzonitrile according to the nucleophilic aromatic substitution polymerization. The chemical structure of PEN random copolymers was characterized by the FT-IR and 1 H-NMR spectrum, respectively. The thermal properties of the PEN random copolymers were investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The resulting PEN copolymers have excellent thermal stability with high glass transition temperature ( T g ) ranging from 187℃ to 271℃ and the 5% weight loss temperature ( T 5% ) of PEN copolymers greater than 490℃ in nitrogen atmospheres. Meanwhile, the PEN films have excellent mechanical property, the tensile strength ranges from 55 to 95 MPa. Moreover, the dielectric properties of the PEN random copolymers were investigated by dielectric tests. The dielectric constants ( k ) and loss tangent (tan δ) of PEN (PEN-6-AF/BHPF100) film is only 2.3 and 0.03 at 1 kHz, respectively. More importantly, the dielectric properties were found to be relatively stable until the T g , which can be attributed to the existence of BHPF units in the molecular backbone.