Tuning the structural and functional properties of HAVOH-based composites via ionic liquid tailoring of MWCNTs distribution

The structural and functional properties of polymer composite materials strictly depend on the spatial distribution of fillers, such as multiwalled carbon nanotubes (MWCNTs), inside the matrix. Herein, novel composites have been obtained by embedding MWCNTs into a modified polyvinyl alcohol (HAVOH) matrix, using the ionic liquid (IL) 1-Benzyl-3-methylimidazolium chloride (BenzImCl) as compatibilizer. The composites were prepared by solvent-wrapping carbon nanotubes onto HAVOH powders, followed by the melt-compounding approach to produce pellets for Fused Deposition Modelling technology (FDM). The efficacy of both the process and the IL on tailoring the spatial distribution of the MWCNTs into the HAVOH matrix is thoroughly studied and correlated with the electrical conductivity of the resulting composites. The sample printed by FDM, containing 6 wt % of MWCNTs and 0.6 wt% of IL exhibited a percolating morphology and led to an electrical conductivity (?) value of 1.2*10 S/m. Moreover, after annealing at 220 °C for 2 h the ? value increased up to 7.9*10 S/m. The thermal treatment in presence of the MWCNTs also induces the formation of crosslinked HAVOH molecules changing the composites from easily soluble to completely water insoluble materials. This revealed the potential of HAVOH-based composites as raw material for FDM technology to realize post-printing cross-linkable materials.