INTEGRATIVE MATERIAL CHARACTERIZATION OF CRYSTALLINE NANOCELLULOSE REINFORCED FILAMENTS FOR FUSED-FILAMENT FABRICATION

Auteurs

Helena W., Stefan W., Joamin G.G.

Référence

ECCM 2022 - Proceedings of the 20th European Conference on Composite Materials: Composites Meet Sustainability, vol. 3, pp. 232-239, 2022

Description

Recently crystalline nanocellulose (CNC) has received increased attention in the scientific community following a universal push for more environmentally conscious engineering and increased sustainability. Due to the combination of high stiffness and low density of CNC, a high specific modulus of approximately 90 MPa/(kg·m3) [1] is achieved. However, during processing via fused filament fabrication (FFF), the material is exposed to a series of thermal and mechanical loads. Therefore, the load history must be considered when characterizing and predicting the composite's properties in the final 3D-printed construction part. A recycled 3D-printable polypropylene modified with CNC up to 15 vol% content was examined in this study. Since the CNC's reinforcement effect is mainly determined by the interactions between the cellulose and the matrix [2], a maleic-acid-anhydride-based compatibilizer was used. To characterize the novel composite shear rheological investigations, dynamic-mechanical analysis (DMA) and measurements regarding shrinkage were performed. An unexpected decrease in viscosity with increasing filler content was observed. This decrease was attributed to (I) the increased use of low viscosity compatibilizer with increased filler content and (II) the thermal degradation of the compatibilizer manifested in a color change of the tested material. This hypothesis was verified by differential scanning calorimetry (DSC) measurements. These measurements enabled a reliable material characterization, which can help to predict the properties of the final printed part.