Solid-State Utilization of Chitin to Construct Flexible Films with Enhanced Biocompatibility and Mechanical Performance

The resource utilization of biomass materials has ignited increasing interest owing to their renewability, biodegradability, and abundance. However, the most representative biomass materials, such as cellulose and chitin, are faced with challenges in terms of the difficulty of thermal processing and the inability of scalable production due to the strong hydrogen bonding between molecular chains. Herein, the large-sized chitin scraps were efficiently pulverized and exfoliated through solid-state shear milling (S-3 M) technology at room temperature. The strong shearing and squeezing force generated from the two pans could further induce the in situ compatibilization of chitin and another environmentally friendly polymer, poly(vinyl alcohol) (PVA). In this way, the flexible PVA/chitin composite film was successfully prepared via thermal processing, attributed to the plasticizing method and perfect film-forming performance of PVA. The ultrafine-pulverized and well-dispersed chitin could effectively promote cell adhesion and proliferation and further enhance the mechanical properties of the composite film in comparison to that without the S-3 M process. This work provides a facile and efficient strategy for solid-state and high-value utilization of biomass materials, for which the traditional processing approaches encounter challenges on a large scale.