Nanocompósito de polianilina e nanofibrilas de celulose.

Abstract

Cellulose Nanofibrils (CNF) have a wide range of applications, since they have high aspect ratio, high crystallinity and mechanical properties besides the important properties of cellulose as low density, biodegradability and come from a renewable source. Polyaniline (PANI) alone has insufficient mechanical properties for applications such as films, but with the incorporation of nanoparticles it is possible to improve such properties. Thus, the polymerization of aniline in the presence of cellulose nanofibrils becomes an alternative in obtaining conductive particles with adequate mechanical properties presenting advantages over pure PANI. Therefore, this work aims to join two types of materials: cellulose nanofibrils (CNF), because they have the capacity to be worked in aqueous suspension and in the form of gels, serving as a "skeleton" of the nanocomposite, and polyaniline, which in turn will assign electrical properties to the material developed. The thermal stability, particle size and other physico-chemical characteristics of this material were evaluated according to the different PANI / CNF ratios. In addition, the syntheses of the pure polyaniline and the PANI / CNF nanocomposite were monitored through the open circuit potential (Voc). The results show that the polymerization time decreases as a function of the increase of the PANI ratio in the nanocomposite, due to the favoring of the polymerization mechanisms. Meanwhile, particle size increases at higher concentrations of PANI, an indication that higher concentration polymerization provides larger polyaniline agglomerates sites. The stability is presented as moderate due to the addition of cellulose nanofibrils, since the pure polyaniline does not present very low stability in aqueous suspension as verified by Zeta potential measurements. Conductivity tests showed values close to those found in the literature (10-1 S.cm-1 samples with 40% polyaniline), indicating that the addition of cellulose nanofibrils did not decrease the electrical properties.