4. Conclusion
In this paper, the investigation
of P(VDF-ter-HFP-ter-TFE) terpolymer additive on Al/MnO2nanothermite system was presented. The terpolymer can stick nanothermite
components together to enhance the integrality of materials. The thermal
properties can be significantly influenced by the contents of
P(VDF-ter-HFP-ter-TFE) terpolymer. Without any terpolymer additive,
thermite reaction between Al and MnO2 occurred at about
554 oC. For 10wt% mass fraction of terpolymer, three
exothermic signals appeared before the main thermite reaction,
indicating the thermal reactions among Al nanoparticles,
MnO2 nanorods, terpolymer degradation products and/or
the terpolymer matrix. However, those three thermal reactions became the
main exothermic reaction instead of thermite reaction when the content
of terpolymer was over 20wt%, and the residues analysis verified the
difference. The main reaction products of Al/MnO2nanothermite were Mn3O4, MnO and
Al2O3. For
Al/MnO2/10wt%- terpolymer, the residues were
MnAl2O3 and
Al2Mn3. When the content of terpolymer
was more than 20wt%, such Mn7C3 and
AlF3 were found in the residues. The ignition and
combustion processes were also different accordingly. The terpolymer
could reduce the ignition energy threshold but also decrease the speed
of flame growth. The terpolymer could hinder the direct contact of
nanothermite components and influence the flame spread. This work
revealed the thermal and combustion performance of
Al/MnO2/ P(VDF-ter-HFP-ter-TFE) terpolymer
nanothermites, which could provide a reference for application of
fluoroelastomer in energetic materials.