Preparation and Properties of Novel Cyclophosphazenes Containing Cyanato Groups

Abstract

Novel cyclotriphosphazenes containing cyanato group (PZCN) derivatives were synthesized by a substitution reaction of 4-hydroxyphenoxycyclotriphosphazenes and cyanogen bromide (BrCN) in the presence of triethylamine (TEA). The PZCNs were characterized by FT-IR, liquid chromatography–mass spectrometry (LC-MS), ¹H NMR, ¹³C NMR, and ³¹P NMR spectroscopy. Curing reactions of the PZCNs were evaluated by FT-IR spectroscopy, thermogravimetry/differential thermal analysis (TG/DTA), and differential scanning, calorimetry (DSC). The PZCNs exhibited an exothermic peak due to curing within the temperature range of 140–300°C by DSC. The PZCNs were completely cured at 220°C. The cured PZCNs exhibited high thermal stability up to 350°C, a high char-forming capability, and electrical properties, such as dielectric constants (Dks) between 2.68 and 2.87, and dissipation factors (Dfs) between 0.008 and 0.013 at 1 MHz.

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