Synergistically enhanced toughness and water vapour barrier performance of polylactic acid by graphene oxide/acetylated lignin composite

• Graphene oxide/acetylated lignin composite. • Polylactic acid/graphene oxide/acetylated lignin composite films. • Synergistically enhanced toughness. • Water vapour barrier performance. Polylactic acid (PLA)/graphene oxide (GO)/acetylated lignin (ACL) composite films were prepared by the solution blending method, and the effects of GO, ACL and GO/ACL on the toughness and barrier performance of PLA were investigated. Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy demonstrated that hydrogen bonds were formed between the carboxyl group on GO and the hydroxyl group on ACL. Particle size analysis revealed that the addition of ACL was able to effectively improve the dispersion of GO in organic solvents, and the average particle size of GO was reduced from 4259 nm to 1734 nm. Compared with GO and ACL, GO/ACL results in greater improvement of the toughness and water vapour barrier properties of PLA, along with a 197% increase in the elongation at break and 26% increase in the water vapour barrier of PLA. Therefore, GO/ACL imparted excellent synergistic toughness and good barrier performance to PLA.