Stable radicals and valence-saturated products of the reaction of nitrogen dioxide with phenylone

It is found that heat-resistant polymer is poly- m -phenylenedimaleimide (“phenylon”) interacts with the nitrogen oxides (2NO2  N2O4) not only with the formation of free radicals, stabilized in the form of iminoxyls, but also the valence of saturated compounds. Based on the mechanism of polymeric free radicals transformation the studied by the EPR method, the authors suggested scheme of the formation of the thermally unstable nitroso - and nitrocompounds of phenylon. The method of thermal gravimetry shows that the accumulation of these compounds deprives “phenylon” of its main property heat resistance. The most important consequence of the process of formation of valence-saturated products of nitration is that “phenylon” must inevitably lose the original high temperature resistance. Indeed, the building up-limousine in the nitro - and nitroso must sooner or later play the role of local thermally destructive (and is even able to local explosions). Note that they accumulate the property of explosiveness even to a greater extent than is typical for polynitroalkanes. Theoretically and experimentally it is shown that under the influence of nitrogen dioxide in the polymer not only stable iminoxyl radicals and valence-saturated nitro - and nitroso-compounds are accumulated. These connections cause a sharp decline in the main operating characteristics of phenylon, namely, its high thermal stability in environments where there is no oxides of nitrogen.