Development of Electrospun Membranes from Silk Sericin-Graft-Polyacrylonitrile Copolymers for Versatile Applications

The use of waste silk sericin (SS), an underutilized biomaterial with antibacterial, antioxidant, and biocompatible properties, is restricted by its inadequate mechanical strength. This underutilization has resulted in significant resource loss and environmental contamination. To promote SS recycling, we performed graft copolymerization with acrylonitrile (AN), initiated by 2,2-azobis(isobutyronitrile) (AIBN), and fabricated sericin-graft-polyacrylonitrile (SS-g-PAN) membranes by electrospinning. The molecular weight and degree of grafting of the copolymer were determined using gel permeation chromatography (GPC) and nuclear magnetic resonance spectroscopy (NMR), respectively. The optimal synthesis parameters were determined at 70 °C for 6 h, with 22 wt % SS and 0.6 wt % AIBN. Membrane performance was thoroughly assessed, revealing its outstanding hydrophobicity, lipophilicity, and UV resistance, indicating its potential applicability in oil–water separation. FTIR spectroscopy and X-ray diffraction analysis validated the grafting process. The thermal analysis revealed a Tg range of 103.56–106.31 °C and a decomposition temperature of approximately 273 °C, which was marginally lower than that of PAN. The membranes exhibited excellent mechanical properties, with a peak tensile strength of 3.59 ± 0.14 MPa and a tensile modulus of 89.45 ± 8.83 MPa. These findings reveal the potential applicability of sericin-based materials in smart wearables, filtering materials, food packaging, environmental protection, and resource reuse.