Antimicrobial Bioplastics: Synthesis and Characterization of Thermally Stable Starch and Lysine-Based Polymeric Ligand and Its Transition Metals Incorporated Coordination Polymer

Potato-based starch was dissolved in distilled water until paste form of starch was found. Paste form of starch polymer by the process of polycondensation reacted with an essential amino acid lysine in a basic medium. The viscous product obtained was then filtered and after a short period of drying was then coordinated with a series of transition metals as Mn(II), Co(II), Ni(II), Cu(II), and Zn(II). The synthesized polymeric ligand and its polymer metal complexes were spectroscopically characterized, thermally analyzed, and biologically evaluated. In this work, FT-IR, 1H-NMR, 13C-NMR, CHN, TGA, SEM, antimicrobial screening, and ASTM- D5338-93, a CO2 evolution method of biodegradable, studies were carried out. The confirmation of the synthesis was done with these instrumental and spectroscopic techniques. Metals-coordinated polymer complexes were found to be more thermally stable and less biodegradable than the virgin parent ligand. Metal-coordinated polymers of all metals were found to be antibacterial and antifungal, with a range of weak to mild zone of inhibition values in agar well diffusion method for antimicrobial studies. Cu(II) polymer metal complex showed the highest value of antimicrobial activity because of the highest stability constant.