In this work, novel polymeric blends were prepared from polyvinyl chloride (PVC) and silkworm cocoon waste (SCW), that were defective cocoons excluded during the silk-making process in the ratio 50:50 w/w. These blends were incorporated with moringa seed oil (MSO) as a bio-based plasticizer with different concentrations (1, 2, and 3%) to obtain a final bioplastic with superior antimicrobial properties. The new composites are characterized through Scanning Electron Microscope (SEM), Fourier Transmission Infrared Spectroscopy (FTIR), contact angle measurements, Thermogravimetric analysis (TGA), dielectric, mechanical, and antimicrobial properties. Results of the study pointed to improved linking between the blend phases after incorporating 2% MSO. The composites could inhibit the growth of all the tested microorganisms. The conductivity σ values increased by increasing the content of MSO in the composite. The results demonstrate the potential of the new MSO plasticized composites as promising candidates for use in hospitals as antimicrobial surfaces.