Enhancing the performance of polylactic acid composites through self-assembly lignin nanospheres for fused deposition modeling

Lignin nanospheres with low cost, high specific surface and good dispersibility have potential high value-added applications. In this study, lignin nanospheres were prepared by dissolving lignin in ethyl acetate (EA), emulsifying, high-speed centrifugation, ultrasonic dispersion and freeze-drying. The particle size distribution of ethyl acetate treated lignin nanospheres (EALNSs) was relatively uniform and concentrated at 200–400 nm, and the thermal stability of the nanospheres was improved to a certain extent. The EALNSs were used as fillers to reinforce polylactic acid (PLA), the processing viscosity of the composites could be effectively reduced, so as to increase the mechanical strength of 3D printing products and significantly enhancing the added value of lignin. The results showed that the EALNSs/PLA composites by adding only 0.50 wt% EALNSs have excellent mechanical properties. Compared with pure PLA, the flexural strength, tensile strength and impact strength of the composites were increased by 130.8%, 56.1% and 14.2%, respectively. Chemical calculation results showed that there was strong hydrogen bond action between EALNSs and PLA. Therefore, the EALNSs/PLA composites can be used as ideal biomass materials for fused deposition modeling.