Figure 3 SEM images of nanothermite samples (a) Al/MnO2 nanothermite, (b) Al/MnO2/10wt%-terpolymer nanothermite, (c) Al/MnO2/20wt%-terpolymer nanothermite, (d) Al/MnO2/30wt%-terpolymer nanothermite
3.2 Simultaneous thermal analysis
We carried out TG-DSC simultaneous thermal analysis tests for Al/MnO2 and Al/MnO2/terpolymer nanothermite samples, as shown in Figure 3. The red curves mean the DSC curves while the black curves represent the TG curves within the temperature range from 100oC to 800 oC.
Figure 4(a) illustrates that the TG-DSC results of Al/MnO2 nanothermite samples. Below 350oC, the total mass continuously loses with the rise of temperature, but there is no obvious endothermic or exothermic DSC signal, which caused by the evaporation of residual solvents, such as free and structural water, ethyl alcohol[28]. The mass is reduced by about 3.0%. Then, in the range of 500 oC ~600 oC, the main exothermic DSC signal appears, indicating that the thermite exothermic reaction between Al NPs and MnO2 NRs occurs. At the same time, no obvious mass changes from TG curve at such temperature range. During thermite reaction, the O element transfers from oxidizer, MnO2NRs, to Al NPs. Thus, no mass change happens. The peak temperature of thermite reaction of Al/MnO2 nanothermite sample is about 554 oC with the 1070 Jg-1 heat release.