All cellulose composites based on cellulose diacetate and nanofibrillated cellulose prepared by alkali treatment

Cellulose diacetate (CDA) composite films were synthesized by incorporation of nanofibrillated celluloses (NFCs), using a casting/evaporation technique. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) characterization indicated the presence of interaction and certain compatibility between CDA and NFCs. The CDA and NFCs were converted to cellulose II by an alkaline treatment which resulted in the formation of all cellulose composite (ACC) films, as indicated by the FTIR and XRD characterization. Significant changes were observed in their structural, thermal, mechanical, and optical transparency properties. The SEM images revealed the excellent compatibility among the constituents of the ACC films. The tensile strength, Young's modulus, and strain at break of the ACC films with 15 wt% NFCs content were increased to 102.3 MPa, 5.8 GPa, 14.7% respectively. This work provides a promising pathway for manufacturing high performance ACC materials.