Preparation and characterization of cellulose nanocomposite films with two different organo-micas

The mechanical properties, morphologies, and gas barriers of hybrid films of cellulose with two different organoclays are compared. Dodecyltriphenyl-phosphonium-mica (C₁₂PPh-mica) and hexadecyl-mica (C₁₆-mica) were used as reinforcing fillers in the fabrication of the cellulose hybrid films. The cellulose hybrid films were synthesized from N-methyl-morpholine-N-oxide (NMMO) solutions with the two organo-micas, and solvent-cast at room temperature under vacuum, yielding 15–20 μm thick films of cellulose hybrids with various clay contents. We found that the addition of only a small amount of organoclay is sufficient to improve the mechanical properties and gas barriers of the cellulose hybrid films. Even polymers with low organoclay contents (1–7 wt %) were found to exhibit much higher strength and modulus values than pure cellulose. The addition of C₁₂PPh-mica was more effective than that of C₁₆-mica with regards to the initial tensile modulus, whereas the addition of C₁₆-mica was more effective than that of C₁₂PPh-mica with regards to the gas barrier of the cellulose matrix. The intercalations of the polymer chains in the clays were examined with wide-angle X-ray diffraction (XRD) and electron microscopy (SEM and TEM).