Spectroscopic and Thermal Characterization of Trimeric to Octameric Phenoxycyclophosphazenes

Abstract

Trimeric to octameric phenoxycyclophosphazenes, [NP(OPh)₂]_n (n = 3 to 8), were isolated and characterized for the compilation of the spectroscopic and thermal analytical data. The NMR and absorption spectra showed similar behavior, except for ³¹P NMR of the trimer. In thermal analysis, the hexamer has the lowest melting point among these phosphazenes, and nonvolatile residues were observed in the hexamers, heptamers, and octamers. The melting points of oligomers were re-evaluated and compared with the values in the literature.

Keywords:

• Cyclophosphazene oligomer
• flame retardant
• phenoxycyclophosphazenes
• spectroscopy
• thermal analysis

Notes

^a In CDCl₃ at 300 MHz.

^b In CHCl₃.

^c Heating rate: 10 °C/min in N₂.

^d Reported values in ref. [2].

^e Reported values in ref. [7].