In-Situ Nanoreinforced Green Bionanomaterials from Natural Keratin and Montmorillonite (MMT)/Cellulose Nanocrystals (CNC)

Biodegradability and renewability has led renewed interest in protein based films reinforced with nanoparticles. Bionanocomposites have gained attention because of their enhanced material properties with the aid of nanoreinforcements. The effects of two different nanoparticles, montmorillonite (MMT) and cellulose nanocrystals (CNCs), at different loading contents (0%, 1%, 3%, 5%, and 10%) were studied as a reinforcement material in modified chicken feather keratin. Compression molding was employed to prepare bionanocomposites films thermoplastically. The effect of CNC and MMT addition, their disposition and impact on the final material properties, was investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile testing, and dynamic mechanical analysis (DMA). The morphology of in-situ-modified keratin-based nanocomposites and the extent of nanoparticle dispersion was observed through scanning electron microscopy (SEM), transmission electron microscopy (TEM) and wide-angle X-ray diffraction (WAXD) respectively. The molecular level interactions of CNC's and MMT's with keratin biopolymer were investigated by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) techniques. Results indicated improved thermal stability and shift in glass transition temperature for both nanoreinforced biocomposites. Tensile strength was enhanced significantly with the addition of MMT; however, increased percent elongation was observed in case of CNC-reinforced biomaterials. The changes in the chemical bonding of keratin biopolymer reinforced with MMT/CNC compared to neat keratin biopolymer were observed by XPS spectra. These results suggest that high performance bionanomaterials can be developed from feather keratin through in situ dispersion of MMT and CNC nanoparticles, followed by compression molding.