Biocomposite films prepared from ionic liquid solutions of chitosan and cellulose

• Published in: Carbohydrate polymers 2012-01, Vol.87 (1), p.435-443
• Main Authors: Stefanescu, Cristina, Daly, William H., Negulescu, Ioan I.
• Format: Article
• Language: English
• Subjects: acetates; Applied sciences; biocomposites; Blends; Cellulose; Cellulose and derivatives; Chitosan; Exact sciences and technology; Fourier transform infrared spectroscopy; freeze drying; Ionic liquid; ionic liquids; methanol; Natural polymers; Physicochemistry of polymers; polymers; scanning electron microscopy; separation; shrinkage; Starch and polysaccharides; thermal degradation; X-ray diffraction
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2011.08.003

► We prepared blends of chitosan and cellulose by using 1-butyl-3-methylimidazolium acetate as solvent media. ► The addition of chitosan increases the thermal stability of cellulose, slowing down its thermal degradation. ► The increased activation energy of the polymeric blends is indicative of enhanced stability reflecting miscibility of the two polymers. ► No apparent phase separation is identified in any of the polymeric blends. Blends of chitosan and cellulose were successfully produced using 1-butyl-3-methylimidazolium acetate (BMIMAc) as solvent media. Films were prepared from the blends by manually spreading the solution on a flat surface and precipitating the polymers in a mixture of methanol and water. To prevent the shrinkage of films, most of the absorbed water was removed by freeze drying under vacuum. Films prepared from the polymeric solutions were investigated by means of FT-IR, TGA, X-ray diffraction and SEM measurements. The shifting of the bands corresponding to –NH and CO groups of chitosan (FT-IR), the absence of the diffraction peaks at 2θ=10.7 and 14.9° (XRD), the increased Ea for thermal decomposition for all the polymeric blends (MTGA), and the presence of an apparent homogeneous structure with no phase separation of the two polymers (SEM) provide evidence for the miscibility between chitosan and cellulose in the solid state.