Results and discussion
The nanocomposites show an increase in the storage modulus with increasing filler content whereas the largest increase is detected for the nanocomposite with the highest filler content. Thus, the mechanical characteristics are successfully improved by the introduction of CNC into the polypropylene matrix while only using reinforcement originating from renewable sources.
The viscosity increases with increasing filler content when determined with a capillary rheometer directly during the extrusion of the filaments. Interestingly, when performing consecutive shear rheological investigations on the extruded filaments, the viscosity decreases with increasing filler content. As the specimens darken during these measurements, this effect is attributed to a thermal degradation of the compatibilizer which highlights the material’s sensibility towards 3D printing. Nevertheless, the nanocomposites kept its printability as proved by several executed prints of the novel material.