Nanocellulose alignment and electrical properties improvement

Auteurs

A. Kadimi, K. Benhamou, Y. Habibi, Z. Ounaies, and H. Kaddami

Référence

in Multifunctional polymeric nanocomposites based on cellulosic reinforcements, D. Puglia, E. Fortunati, and J. M. Kenny (Eds.), Elsevier, pp. 343-376, 2016

Description

Aligning and patterning of nanoparticles with the aim of obtaining unique properties is one of the most interesting research topics in the field of designing and creating advanced materials. This chapter summarizes: (1) the literature (briefly) on cellulose and nanocellulose; (2) some methods of orientation of nanoparticles; and (3) the effect of an electric field on the alignment of nanofibrillated celluloses (NFCs) and on their dielectric properties. In the last part of this chapter, the effect of an electric field on nanocellulose alignment was evaluated as a function of electric field magnitude, frequency, and duration of the applied electric field. Two NFCs extracted from the rachis of a date palm tree, different by aspect ratios, crystalline index, and surface properties, were used and compared to cellulose nanocrystals (CNCs) extracted from the same source. All these nanocelluloses were successfully oriented. However, the optimal parameters of alignment of CNCs are different from those of NFCs. CNCs align easily compared to NFCs. This occurs at lower electric field magnitude. The optimal parameters of alignment for both NFC samples NFC-O-5min and NFC-O-2h were found to be 5000 Vpp mm⁻¹ and 10 KHz for a duration of 20 min. The CNCs align and form chains at lower electric field magnitude in comparison to NFCs. It was also demonstrated that the use of the electric field to align nanocellulose in silicone oil can improve the dielectric constant compared to the random case. One important result is that it was possible to control nanocellulose alignment by dielectric constant measurement. Some parameters such as the crystalline index and surface charges influence the alignment and the improvement of the dielectric constant that can be reached.

Lien

doi:10.1016/B978-0-323-44248-0.00011-0