3. Results and Discussion
3.1 SEM analysis
Figure 3 represents the SEM images
of Al/MnO2 and Al/MnO2/ terpolymer
nanothermite samples. Figure 3(a) is the Al/MnO2nanothermite without the addition of terpolymer. There are two main
structures, nanoparticles and nanorods. The nanoparticles represent the
fuel, Al NPs, while the nanorods are the oxidizer, MnO2NRs. The diameter of Al NPs is in the range of 50 nm ~
100 nm. The rods length is about several micrometers and the diameter of
the rods is merely about 20 nm~ 50 nm. The Al NPs can
directly contact the oxidizer. Besides, the agglomeration phenomenon is
not very clear.
Figure 3(b), (c) and (d) are the
Al/MnO2/terpolymer nanothermite with different contents
of P(VDF-ter-HFP-ter-TFE) terpolymer, from 10wt% to 30wt%
respectively. In Figure 3(b), with 10wt% terpolymer addition, some
terpolymer binder can be found among the nanothermite components. In
fact, the existence of terpolymer is not pretty obvious due to its
content in nanothermite system is not high. So, a fair amount of fuel
still can contact direct oxidizer. When the mass fraction of terpolymer
reach 20wt% and 30wt%, the existence of terpolymer can be more easily
found in Figure 3(c) and (d). As a kind of binder, terpolymer mainly
exist among the components, which can bond the nanothermite components
together to improve the integrity of the materials.