INCREASE OF THE FIRE RETARDANT EFFICIENCY OF INTUMESCENT EPOXY COATINGS BY INTERCALVED GRAPHITE COMPOUNDS

Abstract

Investigation of the effect of nitrate oxide graphite on the parameters of char layer, obtained from the system of ammonium polyphosphate / melamine / pentaerythritol / epoxy resin under the influence of
temperatures of 200–800 °С.  Methodology.  A  fire  retardant  mixture  was  chosen  as  a  model  intumescent  system  ammonium polyphosphate / melamine / pentaerythritol. As a polymer component was used bisphenols A / F epoxy resin together with a polyamidoamine hardener. Nitrate oxide graphite was obtained by oxidation of natural scaly
graphite  with fuming  nitrogen  acid.  The  effect  of  impurities  of  nitrate  oxide  graphite  was  determined  by thermogravimetry  on  the  intumescence  coefficient  of  intumescent  compositions  and  the  mass  of  the  char residue intumescent compositions in temperature range of 200–800 °С.  Findings. The influence of nitrate oxide graphite on the characteristics was studied of char layer of epoxy intumescent system ammonium polyphosphate / melamine / pentaerythritol / epoxy resin. The study of thermal  oxidative  degradation  was  carried  out  intumescent  compositions  in  the  temperature  range  200–800 °С. It was shown that intercalated graphite compounds increase the thermal stability of the formed char layer at temperatures > 600 °С. Determined intumescence coefficients and thermogravimetric analysis of modified intumescent systems was performed nitrate oxide graphite with different degrees of intercalation, in the conditions of 200–800 °С. It was established that the optimal parameters of the char layer are in terms of volume intumescence coefficient and mass of the char residue are provided by graphites, which contain 15–25% of intercalant in its composition. But the results obtained allow us to determine nitrate oxide graphite as a promising modifier of epoxy intumescent systems to increase its fire protection efficiency.
Originality.  The  influence  of  degree  of  intercalation  of  nitrate  oxide  graphite  was  studied  on  the characteristics of char layer of epoxy intumescent system for the first time.  Practical value. The optimal content of intercalant in nitrate oxide graphite was established for the
development of formulations of intumescent epoxy coatings with increased fire retardant properties.