| Affiliation: | 1. Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, Vuorimiehentie 1, Espoo, FI-00076 Finland;2. Department of Civil Engineering, School of Engineering, Aalto University, Rakentajanaukio 4, Espoo, FI-00076 Finland
Integrated Computational Materials Engineering, VTT Technical Research Centre of Finland Ltd., Vuorimiehentie 2, Espoo, FI-02044 Finland;3. Department of Physics, University of Jyvaskyla, Survontie 9, Jyväskylä, FI-40014 Finland;4. Cellulose Coatings and Films, VTT Technical Research Centre of Finland Ltd., Tietotie 4E, Espoo, FI-02044 Finland;5. Institute of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8, Saiwai, Fuchu, Tokyo, 183-8509 Japan |
| Abstract: | A renewable source of carbon black is introduced by the processing of lignin from agro-forestry residues. Lignin side streams are converted into spherical particles by direct aerosolization followed by carbonization. The obtained submicron black carbon is combined with cellulose nanofibers, which act as a binder and rheology modifier, resulting in a new type of colloidal bioink. The bioinks are tested in handwriting and direct ink writing. After consolidation, the black bioinks display total light reflectance (%R) at least three times lower than commercial black inks (reduction from 12 to 4%R). A loading of up to 20% of nanofibers positively affects the cohesion of the dried bioink (1 to 16 MPa), with no significant reduction in light reflectance. This is a result of the superstructuring of the ink components, which disrupts particle packing, intensifies colloidal interactions, introduces light absorption, and non-reflective multiple scattering. |
