Evaluating 3D-printability of polyvinyl alcohol (PVA) and microfibrillated cellulose (MFC) composite inks

Abstract

Polyvinyl alcohol (PVA) is a popular material due to its water solubility and tunable mechanical properties. However, because of its low yield stress in an aqueous solution, PVA is not directly printable using direct ink writing (DIW) 3D printing. To overcome this challenge, this study explored a simple approach of blending PVA with non-chemically modified microfibrillated cellulose (MFC) to form a printable ink for DIW printing. PVA (9.1, 11.1, 13.1 wt%) and MFC (1, 2, and 3 wt%) were mixed to formulate inks with nine different compositions. The printability of the nine inks was evaluated for (1) filament width, (2) printability factor, and (3) stackability of inks in layers. Based on the qualitative analysis of printed structures and evaluation of the print area, the ink compositions of 11.1/2,13.1/2, 9.1/3, and 11.1/3 (denoted as PVA%/MFC%) were selected for further evaluation. Alternatively, the printability factor suggested the compositions of 9.1/2, 9.1/3, and 11.1/3 offered good printability. Finally, the ink of 11.1/2 was used to demonstrate the potential of the PVA/MFC composite ink for DIW 3D printing by stacking 100 layers in a cage structure. This work paves the way to develop sustainable solutions to create DIW-printed structures consisting of PVA and biocompatible additives for various applications, including tissue engineering, packaging, and filtration.