Chitin, a sustainable and functional biological macromolecule, can be converted into chitin nanofibers (ChNFs), and are applicable as a mechanically reinforcing and bioactive filler for polymer matrices. Improving the performance of ChNFs typically relies on their nanofibrilization and miscibility with matrices. To transform chitin biomass into organo-dispersible ChNFs, a series of time-/energy-consuming chemical and mechanical treatments are required: 1) deacetylation, 2) disintegration, 3) surface modification to minimize their aggregation through hydrogen bonds, 4) drying, and 5) re-dispersion. This paper presents a one-step method to transform chitin biomass to organo-dispersible acetylated ChNFs via a ball-milling method in the presence of relatively low toxic acetic anhydride without water. This method minimizes water contaminations and energy for dehydrating. The resulting chitin nanofiber material is mixed with poly(l‑lactic acid) (PLLA) to produce all-bio-based nanocomposites. The composite indicated a 66% increase in Young's modulus and a 100% increase in tensile strength compared to the pristine PLLA. Furthermore, it did not exhibit any observable cytotoxic effect, thus potentially applicable as a biomedical material.
Keywords: Acetylation; All bio-based nanocomposites; Ball-milling; Chitin nanofibers; One-step synthesis.
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