A new method for producing polylactic acid biocomposites for 3D printing with improved tensile and thermo-mechanical performance using grafted nanofibrillated cellulose

• Published in: Additive manufacturing Vol. 61; p. 103346
• Main Authors: Gauss, Christian, Pickering, Kim L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.01.2023
• Subjects: Additive manufacturing; Composite; Nano cellulose; Natural fibre; Surface modification; Natural fibre; Surface modification; Additive manufacturing; Composite; Nano cellulose
• ISSN: 2214-8604; 2214-7810
• DOI: 10.1016/j.addma.2022.103346

In this work, a new methodology was developed to disperse nanofibrillated cellulose (CNF) in polylactic acid (PLA) composites for 3D printing. The nanofibres were modified by grafting PLA onto their surface through in-situ polymerisation of L-lactide. This modification changed subsequent fibre/PLA interaction and enabled the production of reinforced microparticles by a Pickering emulsion approach. We demonstrated that filaments produced with these microparticles containing up to 20 wt% of grafted CNF (g-CNF) can be processed and printed using the same printing parameters as used for neat PLA. The printed samples presented superior tensile properties, enhanced thermo-mechanical stability, and were dimensionally stable upon PLA crystallisation when g-CNF content is above 10 wt%. When heat-treated after printing the composite with 10 wt% of g-CNF achieved an ultimate tensile strength and Young’s modulus of 72 MPa and 5.4 GPa, respectively. Post-printing annealing also increased thermo-mechanical stability of the composites achieving a storage modulus at 80 °C up to 850 times the storage modulus of neat PLA at the same temperature. [Display omitted]