**4. Conclusions**

In this work, two-dimensional MXene (Ti3C2TX) nanosheets were mixed with PBAT by melt compounding. The effects of Ti3C2TX content on the morphology, thermal stability, crystallization behavior, and gas barrier performance of PBAT were investigated. Furthermore, the effects of the biaxial stretching ratio on the gas barrier properties were further discussed. The TGA results showed that the addition of Ti3C2TX improved the thermal stability of the PBAT nanocomposite. In addition, the tensile tests showed that the addition of 1.0 wt% Ti3C2TX improved the maximum tensile stress without losing ductility. The storage modulus of PBAT was significantly improved in the glassy state with the addition of Ti3C2TX. After biaxial stretching, the PBAT-1.0 film (1 × 3) exhibited an oxygen transmission rate of 732 cc/m2·day, which was 28.9% lower than that of pure PBAT casting film. When the stretching ratio was 2 × 2, the WVTR of PBAT-1.0 biaxial stretching film was 6.5 g/m2·day, which was 36.3% lower than that of 1 × 1 PBAT-1.0 film. The enhancement in gas barrier properties can be attributed to the presence of Ti3C2TX nanosheets, which can increase the effective diffusion path length for gases. The results of this work indicate the need for further studies on the influence of the orientation and surface functionalization of Ti3C2TX nanosheets, as well as the incorporation of compatbilizers in the PBAT composite films for packaging applications.

**Author Contributions:** Investigation, X.W., X.L., L.C. and S.F.; writing—original draft preparation, X.W. and X.L.; methodology, X.W. and X.L.; writing—review and editing, Y.L. and S.F.; supervision, Y.L. and S.F. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Natural Science Foundation of Hunan Province (no. 2019JJ50132) and the Innovation Platform Open Fund of Hunan Province (no. 18K079).

**Institutional Review Board Statement:** This study did not involve humans or animals.

**Informed Consent Statement:** This study did not involve patients.

**Data Availability Statement:** The raw/processed data required to reproduce these findings cannot be shared at this time as the data also form part of an ongoing study.

**Conflicts of Interest:** The authors declare no conflict of interest.
