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High-Strength Polylactic Acid (PLA) Biocomposites Reinforced by Epoxy-Modified Pine Fibers

Publication Type
Journal Name
ACS Sustainable Chemistry & Engineering
Publication Date
Page Numbers
13236 to 13247

The stiffness and tensile strength of biopolymers (e.g., polylactic acid (PLA)) are less than desirable for load-bearing applications in their neat form. The use of natural fibers as reinforcements for composites (for large-scale 3D printing) has expanded rapidly attributable to their low weight, low cost, high stiffness, and renewable nature. Silane and acid/alkali are typically used to modify the surface of natural fibers to improve fiber/polymer interfacial adhesion. In this study, a simple method of impregnation was developed to modify pine fibers (Loblolly, mesh size of 90–180 µm, 30 wt%) with a solvent-borne epoxy to reinforce PLA. As a benefit of the epoxy modification (0.5–10 wt%), the tensile strengths and Young’s moduli of the epoxy/pine/PLA composites increased by up to 20% and 82% respectively, as compared to neat PLA. The epoxy/pine/PLA composites with an optimum epoxy modification (1.0 wt%) had fewer voids on the fracture surface, when compared with pine/PLA composites without any epoxy. Results confirmed that epoxy partially penetrated the pore/hollow inner structures of pine fibers and improved the fiber/matrix interfacial adhesion. Epoxy modification is found to be a simple and effective technique to improve the properties of biocomposites.