Dielectric response and molecular dynamics of nanocomposites based on TEMPO-oxidized cellulose nanofibrils and polyvinyl acetate

Abstract

• Two series of nanocomposites based on Polyvinyl-acetate incorporated with two different TEMPO-oxidized cellulose nanofibrils were investigated. • The activation energy and the strength parameters were interpreted. • Electrical conductivity were evaluated using DC measurements. • The comparison between the two sets of CNF showed that PVAc/CNF-5 min films were able to build a denser CNF network and hence the highest potential of filling effect than those of PVAc/CNF-2 h films. A series of polyvinyl acetate polymer matrices (PVAc) incorporated with two different TEMPO-oxidized cellulose nanofibrils (CNF with 5 min and 2 h of oxidation) were studied. These composites have proven to be suitable for use as ion battery separators. For this purpose, dielectric properties and electrical conductivity have been investigated using impedance spectroscopy in the frequency range from 10 2 to 10 6 Hz and over the temperature range, 200–350 K. The effects of CNF loading on the molecular motion and the charge transport mobility in PVAc polymer chains were studied. Calculation of the strength parameter for the α-relaxation process revealed a threshold value of 8 % in the volume fraction of filler. A comparative study of the two nanocomposites films showed that PVAc/CNF-5 min nanocomposites were able to build a denser CNF network and hence the highest potential of filling effect than those of PVAc/CNF-2 h films. According to our results, the volume fraction of 8 % of CNF-5 min is recommended for achieving the highest performing nanocomposite with potential applications.