Boosting the cold flow properties and oxidation stability of diesel-biodiesel blends by novel polymethacrylate graft copolymer nanocomposites

The applications and development of biodiesel fuels are restricted by the poor low-temperature fluidity and oxidation stability. Meanwhile, typical antioxidants are usually compounds containing phenyl groups, which have the disadvantages of high toxicity and carcinogenicity. To address these defects, our study originally synthesized a multifunctional additive using both post grafting and nanocomposite technology, as well as apply a biofuel antioxidant free of benzene ring group, 4-Amino-2,2,6,6-tetramethylpiperidine. Our findings reveal that the delayed crystallization behavior of B20 (20 vol%. biodiesel +80 vol%. diesel) is strongly dependent on the additive structure and amount, which the pour point (PP) and cold filter plugging point (CFPP) are decreased by 20 and 16 °C respectively at 1000 ppm. The post grafting technology enhanced additive antioxidant properties, which extend the induction period of B20 from 2.0 to 6.9 h. Our study confirmed the synthesized additives through possess synergistic enhancement effects on both cold flow properties and oxidation stability. In addition, DFT calculations simulating the potential energy changes of B20 solutions forecast copolymer structure affects the low-temperature fluidity. Hence this study pioneered the proposal for developing multifunctional additives through both post grafting and nanocomposite technology of methacrylate copolymer for biofuels, and provide a theoretical prediction strategy for exploring optimum copolymer pour point depressant for fuels.