**4. Conclusions**

In this work, GA/PA66 composite films were fabricated successfully by the SBS technique. The addition of PA66 resulted in a significant reduction in the diameter of the composite film. The SBS process mixed GA and PA66 into a homogeneous system by forming hydrogen bonding. Compared to the pure gelatin film, the GA/PA66 composite films had higher mechanical strength and the solvent resistance was improved. Overall, the comprehensive observation of GA/PA66 composite films indicated that PA66 can be used as a modified material for gelatin to improve the mechanical properties and solvent resistance, and SBS presents grea<sup>t</sup> promise for the rapid preparation of large area nanofiber film for food packaging.

**Author Contributions:** Data curation, methodology, formal analysis, investigation, writing—original draft, Z.Y.; methodology, formal analysis, C.S.; methodology, formal analysis, Y.Z.; conceptualization, supervision, funding acquisition, writing—review and editing, D.W.; conceptualization, Supervision, H.Z.; supervision, funding acquisition, K.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Zhejiang Provincial Key R&D Program of China (2019C02074) and the Fundamental Research Funds for the Central Universities (K20210202).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

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