Influence and thermodynamic study of metal carbonates on the thermal hazards of nitrocellulose fibers

Nitrocellulose (NC) is a highly flammable and explosive dangerous chemical that can cause thermal runaway accidents during storage and transportation. This study investigated the effects of five common metal carbonates (Na₂CO₃, Li₂CO₃, K₂CO₃, NaHCO₃, and ZnCO₃) on the thermal hazards and reaction kinetics of NC using differential scanning calorimetry (DSC) and a C80 microcalorimeter system. The results indicated that the addition of metal carbonates significantly reduced the initial decomposition temperature and the maximum exothermic temperature of NC, increased the heat of exotherm and decreased the reaction activation energy, accelerating the thermal decomposition process of NC. Among these, K₂CO₃, NaHCO₃, and ZnCO₃ showed noticeable catalytic effects, with K₂CO₃ exhibiting the most significant enhancement. Kinetic analysis based on the Kissinger method and the FWO method showed that K₂CO₃ significantly reduced the activation energy of NC, accelerating its decomposition process. The thermodynamic model further proved that K₂CO₃ significantly reduced the self-accelerating decomposition temperature of NC. The results revealed the serious incompatibility between NC and metal carbonates (especially K₂CO₃), exacerbating the thermal risk. Future studies should explore safer alternatives or stabilizers for NC-based systems.