Polyvinyl alcohol reinforced with carbon nanotubes for fused deposition modeling

For the first time, nanocomposite filaments consisting of polyvinyl alcohol and carbon nanotubes were successfully used for additive manufacturing by fused deposition modeling. Polyvinyl alcohol and carbon nanotubes were mixed in a water solution using hexadecyl trimethyl ammonium bromide as a surfactant. Filaments with various concentrations of carbon nanotubes (up to a maximum content of 3 wt.%) were obtained with a single screw extruder and used to feed a commercial desktop 3D printer. Carbon nanotubes increase the glass transition temperature of the printed samples; however, the presence of CTAB reduces this effect. The viscosity of the material increases with the addition of carbon nanotubes and the 3D-printed samples become tougher as the carbon nanotubes amount increases. Elastic modulus and creep compliance are remarkably improved by the presence of carbon nanotubes, while ultimate mechanical properties are not affected. The high reduction of electrical resistivity found on the filaments was not found on the 3D-printed samples. This was attributed to the prevalent location of carbon nanotubes in the core region of the 3D-printed samples as documented by scanning electron microscopy.