Fabrication of solvent-free hollow PAN microspheres with an easily-assembled double-T emulsion generator

Abstract

In this study, the solvent-free polyacrylonitrile (PAN) microspheres were successfully fabricated using an easily -assembled double-T emulsion generator. The effects of removing solvent methods and CO2 replacing period during the supercritical drying on the PAN microspheres were ascertained. As suggested from the experimental results, the supercritical drying method could more effectively remove solvent than the vacuum drying and solvent washing. After the supercritical drying, the sphericity of PAN microspheres remained, and the percentage contraction was less than 5%. By Stereomicroscope, Field Emission Scanning Electron Microscope (FESEM), energy dispersive X-ray analysis (EDS), confocal microscope as well as white light interferometer, the solvent-free PAN microspheres structures were characterized. There was a trace amount of Si after treatment, whereas it was found to be almost removed, which satisfies the experiment requirements. By contrasting the results of the treatments with different CO2 replacing periods in the supercritical drying, the replacing period of 2 h was found as the optimal condition. In the future, the solvent-free PAN microspheres will have a potential application in the inertial confinement fusion experiment.