Rapid Fabrication of High-Strength, Water-Resistant Chitin Micro–Nanofiber Films as Bioplastics

Petroleum-based plastics pose serious environmental issues due to their nondegradability, driving the development of biobased alternatives. However, common bioplastics such as polylactic acid still suffer from limited mechanical and thermal performance. Chitin micronanofiber films are promising alternatives due to their degradability and good mechanical properties, yet their poor water resistance limits broader application. In this work, high-performance chitin micronanofiber films were fabricated via a simple dissolution-regeneration strategy with rapid zinc chloride treatment (10 s). The resulting films exhibited good properties, including a dry strength of ∼170 MPa, wet strength of ∼51 MPa, coupled with a good light transmittance of ∼90% and a low haze of ∼4.0%. They also demonstrated good thermal stability, flame retardancy, biodegradability, and recyclability. Notably, the recycled films maintained a dry strength of ∼105 MPa and a transmittance of ∼83%. The developed films are promising bioplastic alternatives for flexible packaging and transparent electronic substrates.