High Strength Nanostructured Films Based on Well-Preserved β-chitin Nanofibrils
Chitin nanofibrils (ChNF) are interesting high-value constituents for nanomaterials due to the enormous amount of waste from the seafood industry. So far, reported ChNF:s are substantially modified and chemically degraded (shortened) during extraction from the organisms. Here, highly individualized and long native-state β-chitin nanofibrils from Illex Argentinus squid pens are prepared. A mild treatment was developed to preserve molar mass, aspect ratio, degree of acetylation and crystallite structure. The fibrils show uniform diameter of 2-7 nm, very high aspect ratio (up to 750), high degree of acetylation (DA = 99%), and high molar mass (843,500 Dalton). The powder X-ray diffraction analysis showed preserved crystallite structure after protein removal. These “high quality” ChNF:s were used to prepare nanostructured films via vacuum filtration from stable hydrocolloids. The effects of well-preserved “native” fibrils on morphology, and film properties (mechanical and optical), were studied and compared with earlier results based on coarser and shorter, chemically degraded chitin fibrils.