Examining the Influence of Organophosphorus Flame Retardants on the Thermal Behavior of Aromatic Polybenzoxazines

2,2‐bis(3,4‐Dihydro‐3‐phenyl‐2H‐1,3‐benzoxazine)propane (BA‐a) is blended with three commercial organophosphorus compounds, bis(4‐ hydroxyphenyl)phenylphosphine oxide (BHPPO), diphenyl phosphorami‐date (DPPA), and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), at different loadings (1–10 wt%). Incorporation of all dopants results in a reduction in the initiation temperature for the curing mechanism (by some 30–60 K), but only the...