Mechanically robust polyurea nanofibers processed through electrospinning technique

This paper deals with the fabrication of non-woven polyurea nanofibers through an electrospinning process and evaluation of their mechanical properties under dynamic conditions. Polyurea is finding increasing applications for protection against dynamic loads like blast and ballistics. Processing polyurea into nanofibers can further improve their properties, especially with respect to mechanical properties and high surface areas, expanding their field of application. Till date, electrospinning has not been explored to prepare polyurea nanofibers. In the present work, segmented polyurea based on polypropylene oxide polyetheramine and isocyanate was processed into nanofibers and the influence of the electrospinning parameters on fiber morphology was studied. Uniform nanofibers could be obtained with polymer concentration> 25 %w/v, tip to collector distance< 20 cm, while maintaining a potential difference> 20 kV. Strain sweep and frequency sweep tests revealed dependence of the linear viscoelastic region of nanofibers on test temperature and the loss factor on frequency respectively.