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

MXene modified by stearic acid (Ti3C2Tx-g-SA) is incorporated into poly(lactic acid) (PLA) matrix to prepare Ti3C2Tx-g-SA/PLA composites. The effects of Ti3C2Tx-g-SA to pure PLA are investigated, including crystallization, mechanical, and thermal properties. Fourier transform infrared spectroscopy and X-ray diffraction analyses confirm that Ti3C2Tx interlayer is successfully intercalated by SA, and the interlayer spacing of Ti3C2Tx is increased. Differential scanning calorimetry illustrates that the cold crystallization enthalpy (Delta H-cc), melting enthalpy (Delta H-m), and crystallinity (X-c) of Ti3C2Tx-g-SA/PLA composites are improved by the plasticization and heterogeneous nucleation effect of Ti3C2Tx-g-SA. Specially, the Ti3C2Tx-g-SA/PLA composites exhibit excellent mechanical properties at an appropriate content of the Ti3C2Tx-g-SA. Compared with pure PLA, the elongation at break of the Ti3C2Tx-g-SA/PLA composite is increased 5.9-fold (up to 131.6%) when only containing 0.5 wt % Ti3C2Tx-g-SA. Besides, the Ti3C2Tx-g-SA/PLA composites exhibit good thermal stability in the low loading (lower than 1 wt %) of Ti3C2Tx-g-SA. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48621.