3D‐Printed Wood‐Fiber Reinforced Architected Cellular Composites

Enhancing thermomechanical properties of bio-based polymers by the introduction of cellulose-based compounds not only paves the way for developing sustainable materials but also opens new opportunities in low-cost additive manufacturing. Herein, a novel accessible methodology is provided for integrating waste wood fibers, a versatile renewable resource of cellulose, into polylactic acid (PLA) polymers to produce sustainable wood-fiber reinforced PLA (WF-PLA) filaments and then to 3D print high-performance architected cellular composites. The experimental results demonstrate increased stiffness (18%), ultimate strength (9%), fracture strain (15%), toughness (44%), thermal conductivity (23%), and reduced overall density (10%) for 3D-printed composite dogbones made of optimum wood-fiber contents, compared with the PLA counterpart. Following the growing interest in architected cellular solids, a rising class of advanced materials with superior multifunctional properties, WF-PLA filaments are used to 3D print two quasi-isotropic cellular materials, hexagonal and novel mixed square ("isomixed") microarchitectures. The WF-PLA isomixed cell exhibits considerably enhanced stiffness (91%) and ultimate strength (48%) compared with the PLA hexagonal honeycombs. The WF-PLA architected composites offer a first-of-a-kind strategy to additively manufacture sustainable advanced materials with enhanced thermomechanical properties out of low-cost waste materials through an optimized material composition and the rational design of underlying microarchitectures.