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Polyarylene ether nitrile sulfone (PENS) random copolymers consisting of polyarylene ether nitrile (PEN) and polyarylene ether sulfone (PES) were prepared from bisphenol A, bis(4-chlorophenyl)sulfone, and 2,6-dichlorobenzonitrile by the nucleophilic aromatic substitution polymerization. The structure of the PENS random copolymers was confirmed by Fourier transform infrared spectrometer and 1H nuclear magnetic resonance, and the properties of the PENS copolymers were investigated by thermal analysis (differential scanning calorimetry and thermogravimetric analysis), inherent viscosity measurements, mechanical tests, and dielectric tests. The samples showed excellent thermal stability, with the 5% weight loss temperature (T 5%) greater than 480°C under nitrogen and glass transition temperature (T g) greater than 180°C. The tensile strength, tensile modulus, and elongation at break of the PENS copolymers were improved with the increase of the PEN content, indicating the better mechanical property of PEN than that of PES. The dielectric constant and dielectric strength of the PENS random copolymers were also enhanced with the increase of the PEN content. As a result, PENS100 showed the highest energy storage density, which is 0.68 J/cm3. PES showed better thermal properties while worse mechanical and dielectric properties compared with PEN. PENS copolymers combined the excellent properties of PEN and PES due to the compatibility between them. [ABSTRACT FROM AUTHOR]

Poly(arylene ether nitrile) (PEN) copolymers (HQ/RS-PEN) containing different proportions of hydroquinone (HQ-PEN) block and resorcinol (RS-PEN) block were synthesized, and their crystalline, mechanical, and dielectric properties were investigated. Three HQ/RS-PEN copolymers with 10%, 20%, and 30% of RS-PEN blocks were prepared via condensation polymerization of HQ and RS with 2,6-dichlorobenzonitrile. The PEN copolymers were characterized and confirmed by Fourier transform infrared spectroscopy, intrinsic viscosity, and thermal analyses. With the addition of RS-PEN block, the flexibility of PEN copolymers was increased. In addition, even though the high loading content of RS-PEN block was incorporated, the PEN copolymers still exhibited relatively high dielectric constant, whereas the dielectric loss decreased. Furthermore, to investigate the effect of treatment time and temperature on the physical properties of crystalline PEN copolymers, HQ/RS-PEN20 was isothermally treated at different temperatures (280°C, 300°C, 310°C, 320°C, and 330°C) for a constant time and at a constant time for different hours (1, 2, 3, 4, and 5 h). After the optimization of the crystallization of HQ/RS-PEN polymer, excellent mechanical and dielectric properties of copolymers were obtained. The results showed that when isothermally treated at 320°C for 2 h, the HQ/RS-PEN20 showed optimal properties of tensile strength of 117.6 MPa and dielectric constant of 4.07 at 1 kHz. [ABSTRACT FROM AUTHOR]