Effects of typical additives on the thermal stability of ammonium peroxydisulfate

Ammonium peroxydisulfate (APS), one of the most widely used inorganic peroxides in the process industries, is a thermally unstable peroxide and potent oxidizer due to the presence of peroxy bond in the molecule and is incompatible with most substances. To investigate the effect of typical additives on the thermal decomposition of APS, in this paper, diamine phosphate (DAP), monoamine phosphate (MAP), and aluminum hydroxide (AH) were selected as additives; pure APS and samples with 10 wt% and 20 wt% of additives were first tested by differential scanning calorimetry (DSC). The experiments and analysis showed that the samples with 10 wt% of additive had better thermal stability than those with 20 wt% of additive. After screening, the three groups of 10 wt% AH, 10 wt% MAP, and 20 wt% MAP additive conditions could be considered to have a better thermal stability effect on the thermal decomposition of APS. Four groups of samples were, in turn, tested by Phi-Tec II. The adiabatic results showed two discontinuous exothermic processes; 10 wt% AH promoted the weak exothermic effect in the first stage. In contrast, the three groups of additives in the main exothermic stage showed different degrees of inhibition, and the inhibiting effect was ranked as 10 wt% AH, 10 wt% MAP, and 20 wt% MAP in order. Finally, the self-accelerated decomposition temperature (SADT) was calculated under the 25 kg standard package. The adiabatic results, including SADT, were combined to render feasible recommendations for the use of additives, which provides references for the packaging and transportation of additives and their applications.