A Novel Natural Fibers-Based Bio-composite Prepared from Silk Fibroin and Luffa Cylindrica

Herein, the novel bio-based co-polymer was synthesized using only natural fibers by way of co-dissolving cellulose extracted from Luffa Cylindrica (LC) and silk fibroin (SF) in formic acid in different weight ratios (3SF/1LC, 2SF/2LC, and 1SF/3LC). The prepared bio-composite films were investigated by morphological, vibrational, structural, thermally, and wettability with Scanning electron microscope (SEM), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and water contact angle (WCA). The surface and cross-section SEM images of samples indicate that all films have homogeneous structures, and by varying the ratio of silk fibroin in blend films, a smoother and glassier appearance was obtained, as also proved by XRD and DSC results. The results of the FT-IR test reveal that the changing and shifting of peak intensities in the spectroscopy of bio-composite films indicate interactions between luffa cellulose and silk fibroins. XRD results show that silk fibroin enhances the crystallinity of bio-composite specimens. In addition, thermogravimetric analysis demonstrates that increasing the cellulose ratio in bio-composite films extends their thermal stability. The glass transition value provided by the DSC test proves that the flexibility of hybrid bio-composite films increases as the ratio of luffa increases. As a final analysis, WCA states that when blended with luffa and silk fibroin, although both are hydrophilic, the hybrid bio-composite films display hydrophobic properties, and LC increase enhances this behavior against water. The combination of these two materials can be used in environmentally friendly in medical applications (tissue engineering, wound dressings, etc.) and agricultural fields.