Fabrication of cellulose nanoparticles through electrospraying.

This study reports the fabrication of cellulose nanoparticles through electrospraying the solution of cellulose in N,N-dimethylacetamide/lithium chloride solvent as well as investigating the effect of electrospraying conditions and molecular weight on the average size of electrosprayed nanoparticles. Electrospraying of cellulose was carried out with the following range for each factor, namely concentration = 1-3 wt%, voltage = 15-23 kV, nozzle-collector distance = 10-25 cm, and feed rate = 0.03-0.0875 ml/h. The smallest nanoparticles had an average size of around 40 nm. Results showed that lowering the solution concentration and feed rate, as well as increasing the nozzle-collector distance and applied voltage led to a decrease in the average size of the electrosprayed cellulose nanoparticles. Fourier transform infrared analysis proved that no chemical change had occurred in the cellulose structure after the electrospraying process. According to X-ray diffraction (XRD) results, cellulose nanoparticles showed a lower degree of crystallinity in comparison with the raw cellulose powder. XRD results also proved the absence of LiCl salt in the electrosprayed nanoparticles.

Analytical assessment of woven fabrics under vertical stabbing - The role of protective clothing.

Knives are being used more commonly in street fights and muggings. Therefore, this work presents an analytical model for woven fabrics under vertical stabbing loads. The model is based on energy method and the fabric is assumed to be unidirectional comprised of N layers. Thus, the ultimate stab resistance of fabric was determined based on structural parameters of fabric and geometrical characteristics of blade. Moreover, protective clothing is nowadays considered as a strategic branch in technical textile industry. The main idea of the present work is improving the stab resistance of woven textiles by using metal coating method. In the final, a series of vertical stabbing tests were conducted on cotton, polyester and polyamide fabrics. Consequently, it was found that the model predicts with a good accuracy the ultimate stab resistance of the sample fabrics.