Heat-resistant aromatic S-triazine-containing ring-chain polymers based on bis(ether nitrile)s: Synthesis and properties

A novel series of aromatic s-triazine-containing ring-chain polymers, which typically require high pressures to produce, were prepared by the bulk polymerization of low-melting bis(ether nitrile)s (BENs) with or without the presence of terephthalonitrile (TPH) in the catalysis of ZnCl2 under normal pressure. Four kinds of BENs were readily synthesized by the nucleophilic displacement reaction of 4-chlorobenzonitrile with commercially available aromatic bisphenols or bisphenol-like monomers. Chemical structure of the obtained BENs and their polymers was characterized by FT-IR, WAXD and elemental analysis. Conversion studies indicate that cyano concentration, mobility and reactivity are all important factors for the polymerization, while among of them the cyano reactivity plays a dominant role. The addition of a small mount of TPH is found to be effective in promoting s-triazine forming reaction of the BENs. The synthesized polymers are insoluble, and exhibit good chemical-resistant property towards strong acids and bases together with good hydrolysis-resistant property. No detectable endothermic inflection for glass transitions is observed in the DSC traces of all polymers up to 450 °C, and the polymers exhibit excellent thermal stability with decomposition temperatures for 5% mass-loss ranging from 493-540 °C. All these attracting properties make the s-triazine-containing ring-chain polymers good candidates as matrixes for high performance polymeric materials.