(601g) Biobased Carbon Nano-Onions and Their Applications in Nanoengineered Composites

Carbon nano-onions, consisting of quasi-spherical- and polyhedral-shaped graphitic layers close to one another, have many potential applications due to their unique structures. However, its high costs and the difficulty of scaled production hinder its wide applications. In this work, we developed an efficient and robust synthesis method to produce biobased carbon nano onions (BCNO) using lignin at low costs. Our BCNOs with tunable oxygenated functionalities and nanocrystal sizes also had excellent solubility in various solvents. As an example of its potential application, the BCNOs were used as fillers to develop property-enhanced PLA composites. It showed that adding 0.5% of BCNOs in PLA could increase tensile strength from 67 MPa to 92.8 MPa and tensile modulus from 2.5 GPa to 5.88 GPa. It was also found that adding 0.5% of BCNOs to a PLA composite with 10% soybean-based hyperbranched elastomer (SBCP) could increase tensile strength and modulus by 18.3% 179.5%, respectively, while also increasing tensile strain at break by 2225.3%, compared to pure PLA. Without BCNOs, PLA-SBCP composite increased the strain at break but reduced tensile strength and modulus. The addition to tensile properties, BCNO fillers could also improve the IZOD impact strength, flexural strength, and thermal stability of PLA composites. Our results show that BCNOs can be used as a low-cost filler to produce nanoengineered materials with superior performance.