The Influence of Substituents in Phosphazene Catalyst-Flame Retardant on the Thermochemistry of Benzoxazine Curing

Curing of DER-331 Epoxy Resin with Arylaminocyclotriphosphazenes Based on o-, m-, and p-methylanilines

As a result of this research, it was established that the chlorine atom replacement rates in hexa-chlorocyclotriphosphazene by o-, m-, and p-methylanilines' temperatures are crucial in determining which reaction is made. The speed of reaction practically does not affect the polarity of the synthesis solvent. For the formation of fully substituted o-, m-, and p-arilaminocyclotriphosphazenes, the reaction takes 5 h and is carried out in the diglyme at its boiling temperature. The structure of the synthesized AAP was confirmed by ³¹P and ¹H NMR spectroscopy and MALDI-TOF mass spectrometry. By means of synchronous DSK and TGA, it is found that the synthesized AAP are crystalline and their thermal destruction has a stepped character. Thermal destruction is shown to be accompanied by the simultaneous removal of three aniline molecules from the AAP molecules. Conducted curing of epoxy resin DER-331 is carried out using the AAP as a curing agent. It has been established that due to steric difficulties, o- AAP does not interact with epoxy resin, unlike m- and p- AAP. The gel fraction in curing resin is measured, and the AAP relate to the stage processes of macromolecule formation. The result is that polymers based on DER-331 and m-, p-AAP have a gel fraction content up to 97 mass. %. These polymers have glass-transition temperatures 80 and 85 °C (m- and p-AAP-based, respectively) and demonstrate fire resistance to standard UL-94 of category V-0.