Positive effects of PVP in MIC: Preparation and characterization of Al-Core heterojunction fibers

The core-shell metastable intermolecular composites (MIC) have attracted much attention in the past few years due to their unique properties. Here, the preparation of Al-Core heterojunction fibers using PVP as a template is proposed. The nano-Al was directly added to the precursor solution of cupric acetate monohydrate (CAM)/Polyvinylpyrrolidone (PVP), and the initial Al@CAM/PVP fibers were obtained via electrospinning. The core-shell MIC fibers are then obtained by calcining the initial fibers. The morphology, structure, and composition of Al-core MIC fibers were characterized, that the energetic fibers calcined at 300 °C, 350 °C, and 400 °C have a core-shell structure with shell compositions CuxO and PVP, CuxO and CuO, respectively. The energy release characteristics of Al-core MIC were investigated, and preliminary ignition tests were performed using an ignition temperature measuring instrument and a pulsed laser. The energetic fibers calcined at 300 °C exhibited unique properties. The decomposition of PVP in the shell layer promoted exotherm, and a low-temperature exothermic peak was shown at 372–458 °C. Lower ignition temperatures and higher flame heights were observed in the combustion tests than calcination at 350 °C and 400 °C. An unexpected result was that PVP can play a positive role in Al/CuO nanothermites. Simultaneously, this preparation method provided an idea for the integrated preparation of core-shell Al-Core MIC fibers and tuning the properties of MIC.