Molding of all-cellulose plates made of cellulose pulp extracted from citrus fruit residue

Cellulose is photosynthesized by plants from carbon dioxide and water, and it is the most abundant organic compound available. It is present in the plant cells as structural component in the form of elementary fibrils known as nanofibers. Cellulose nanofibers can be easily extracted from parenchyma tissues of agricultural waste. Although thin sheets made of cellulose nanofibers can be readily obtained by a papermaking method, thicker plates are difficult to make. Here we propose a papermaking-like method to fabricate 1 to 2 mm-thick plates from citrus fruit residue-derived cellulose pulp initially having a solids content of about 1%. The protocol is simple, easy, requires affordable devices and relies on water evaporation to consolidate the fibrils by hydrogen bond interconnections. The pulp morphology seems to consist mostly of cellulose nanofibers and the bending strength and modulus of obtained plates reached 190 ± 30 MPa and 9.6 ± 1.5 GPa, respectively, values that approach those reported in a previous study that molded microfibrillated cellulose but relying on a complex process. This streamlined protocol could be groundwork for further studies aiming the difficult task of molding cellulosic materials.