The relationship between the molecular structure and properties of novel poly(arylene ether nitrile ketone)s with high-temperature and stable dielectric properties

Three new poly(arylene ether nitrile ketone)s (PENKs), special engineering plastics, with different molecular structure were prepared. The obtained PENKs were characterized by FTIR spectroscopy. The thermodynamic and heat resistance behavior of PENKs were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. It was noticed that the glass transition temperature (T g ) and initial decomposition temperature (T i ) of the PENKs were higher than 160 and 480°C, respectively. The main reason was due to their molecular structure, in which the stronger intermolecular forces improved the heat resistance. Moreover, the crystallinity of PENKs decreased with increasing the nitrile group (–CN) content, which indicated that the regularity of molecular chain decreased. The dielectric property indicated that the dielectric constant (K) of PENKs increased with–CN content because of its strong polarity. Meanwhile, the T g of PENKs was higher than traditional poly(ether–ketone) (PEK) and poly(ether–ether–ketone) (PEEK). It was important that the solubility of PENKs was well improved. Besides, the tensile strength of PENKs was higher than that of common poly(arylene ether nitrile) (PEN).