Synthesis and crosslinking behavior of a soluble, crosslinkable, and high young modulus poly(arylene ether nitriles) with pendant phthalonitriles

Abstract

AbstractPoly(arylene ether nitriles) (PEN) with pendant phthalonitrile groups (PENCN) were obtained via the Yamazaki‐Higashi phosphorylation route of 4‐(4‐aminophenoxy)phthalonitrile (APN) with acid‐contained PEN (PENCOOH) in the presence of CaCl2. The chemical structure and molecular weight of PENCN were characterized by 1H‐NMR, Fourier transform infrared spectroscopy, and Gel permeation chromatography. The synthesized PENCN had superior solubility in polar organic solvent and can be easily processed into thin films from the solutions of N‐methylpyrrolidone, dimethylsulfoxide, N,N′‐dimethylformamide, dimethylacetamide, and tetrahydrofuran. Compared with PENCOOH, PENCN showed higher thermal stability with 5% weight loss temperatures (T5%) up to 430°C. The glass transition temperature of PENCN was improved from 211 to 235°C measured by differential scanning calorimetry (DSC). In addition, it also exhibited excellent mechanical properties that Young's modulus reached to 3.5 GPa. Meanwhile, the effects of different aromatic amines and Lewis acid on the crosslinking behavior of PENCN were investigated by DSC. The results indicated that anhydrous Zinc chloride (ZnCl2) was the best catalyst to lower the curing temperature among 2,6‐bis(4‐diaminobenzoxy) benzonitrile, 4,4‐diaminediphenyl sulfone, APN and ZnCl2. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012