Enhanced mechanical properties of poly(lactic acid) composites with ultrathin nanosheets of MXene modified by stearic acid

MXene modified by stearic acid (Ti 3 C 2 T x ‐g‐ SA) is incorporated into poly(lactic acid) (PLA) matrix to prepare Ti 3 C 2 T x ‐g‐ SA/PLA composites. The effects of Ti 3 C 2 T x ‐g‐ SA to pure PLA are investigated, including crystallization, mechanical, and thermal properties. Fourier transform infrared spectroscopy and X‐ray diffraction analyses confirm that Ti 3 C 2 T x interlayer is successfully intercalated by SA, and the interlayer spacing of Ti 3 C 2 T x is increased. Differential scanning calorimetry illustrates that the cold crystallization enthalpy (Δ H cc ), melting enthalpy (Δ H m ), and crystallinity ( X c ) of Ti 3 C 2 T x ‐g‐ SA/PLA composites are improved by the plasticization and heterogeneous nucleation effect of Ti 3 C 2 T x ‐g‐ SA. Specially, the Ti 3 C 2 T x ‐g‐ SA/PLA composites exhibit excellent mechanical properties at an appropriate content of the Ti 3 C 2 T x ‐g‐ SA. Compared with pure PLA, the elongation at break of the Ti 3 C 2 T x ‐g‐ SA/PLA composite is increased 5.9‐fold (up to 131.6%) when only containing 0.5 wt % Ti 3 C 2 T x ‐g‐ SA. Besides, the Ti 3 C 2 T x ‐g‐ SA/PLA composites exhibit good thermal stability in the low loading (lower than 1 wt %) of Ti 3 C 2 T x ‐g‐ SA. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48621.