Biomaterials from wool wastes: characterization of cortical cells/chitosan composite

Anisotropic cortical cells were extracted from waste wool fibres by formic acid-ultrasonic treatment and successively included in different proportions in a chitosan matrix to make film-forming composites, suitable for film casting and filament spinning. The morphological, chemical, thermal and mechanical properties of the composite film were investigated by scanning electron microscopy (SEM), light microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetric (DSC) and tensile tests, respectively. The cortical cells/chitosan composite is capable of forming translucent composite films with acceptable mechanical and thermal properties. The chitosan composite film with addition of 30 wt.% cortical cells showed values of 29.6 +/- 2.9 MPa for ultimate strength, 5.6 +/- 0.3% for ultimate elongation and 35.3 +/- 1.4 MPa for Young's modulus, all higher than that of the pure chitosan film. DSC results revealed that the decomposition temperature of the composite film shifted to a higher temperature compared to the base materials, by increasing the mass fraction of cortical cells. XRD patterns showed that the crystallinity of biocomposite films increased with the addition of cortical cells. In addition, the FT-IR spectra of the composite film indicated that no chemical reaction occurs between cortical cells and chitosan; only a physical mixture of its constituents was present.