3D printing of modified soybean hull fiber/polymer composites

Herein, we have evaluated the soybean hull derived fibers as reinforcements to manufacture thermoplastic copolyester (TPC) composites using 3D printing process namely fused filament fabrication (FFF). The hulls were subjected to physical and chemical treatments to understand their influence on the microstructural and mechanical properties of the composites. We found strong dependence of surface quality, printing defects and interbead/interlayer bonding on the fiber treatment. The composites made using dilute acid hydrolysis treated fibers increased the relative density of the composites to 99% and reduced the pore size from 81 mu m to 39 mu m. Defect free fiber-matrix interfacial characteristics in these composites enhanced the elastic modulus from 36 MPa to 54 MPa. Similarly, the toughness and stress at 50% strain of these composites were similar to 30% and 50% higher than the pure TPC, respectively. Our results clearly demonstrated that the low-cost and abundantly available soybean hulls when modified using dilute acid hydrolysis have a strong potential in the fabrication of natural fiber reinforced composites.