The role of polymers in nano-aluminum@polymer microspheres fabricated by electrospray

Polymers act as binder in fabrication of electrosprayed nano-aluminum@polymer microspheres, which hold the nano-aluminum particles together and maintain the geometry and mechanical properties. The roles of three kinds of polymers (NC, GAP and F2602) during heatingwere explored through analyzation of the polymers adsorptions, microstructures and thermal behaviors of microspheres. The results show that the microspheres are in uniform morphology and high dispersion. Different surface Al-OH groups of nano-aluminum result in different types of adsorption of polymers and different reaction between polymers and nano-aluminum particles during heating process. The specific area of electrosprayed nano-aluminum@polymer microspheres is basically equivalent to the individual nano-aluminum particles, which results in a similar oxidation reaction mechanism of micron electrosprayed microspheres and nano-aluminum particles. The heat released by decomposition of the polymer will facilitate the saperation of microspheres in varying degrees during the heating process, and the gaseous oxidizer produced by polymer decomposition will react with nano-aluminum. Some nano-aluminum@polymer microspheres appear higher reaction ratio and severer oxidation process of nano-aluminum in the temperature range of 400~600℃ because the residue of polymer decomposition adheres on the nano-aluminum surface and hinders the diffusion of oxygen on the surface of nano-aluminum and thus, allows the control of oxidation rate. The optimal element composition and heat release can be decided by coordinating the proportion and types of polymers to meet various application demands.