Influence of Ammonium Formate Content on Rheological and Thermal Decomposition Properties of On-Site Mixed Emulsion Matrix

To enhance the heat-resistant performance of on-site mixed emulsion explosives, four kinds of on-site mixed emulsion explosive matrix samples were prepared by adding ammonium formate with different concentrations into corresponding aqueous phase system, respectively. The fluidity, viscoelasticity, viscosity-temperature, and thermal decomposition properties of the four kinds of samples were investigated through rotational rheometer and synchronous thermal analyzer. The results revealed that the addition of ammonium formate increases the viscosity of the on-site mixed emulsion matrix, and the viscosity of the four kinds of samples exhibits a trend of first increase and then decrease with the increase of ammonium formate mass fraction. Compared with the sample without ammonium formate, the addition of ammonium formate improve the elastic modulus of the emulsion matrix and enhances its stability. When the mass fraction of ammonium formate is not greater than 9%, the viscosity of the emulsion matrix at around 50 ℃ meets the pumping requirements. The addition of ammonium formate shows no significant influence on the thermal decomposition process of the emulsion matrix. However, as ammonium formate mass fraction increases, the extrapolated initial decomposition temperature, activation energy, thermal explosion critical temperature, as well as self-accelerating decomposition temperature all increase, leading to improved thermal stability and thermal safety of the on-site mixed emulsion matrix.