Preparation and Characterization of PLA/Polypyrrole Blends with Antibacterial Properties

We discuss the preparation of Polypyrrole and Polylactic Polyacid (PPy/PLA) based blends and the subsequent investigation of their antibacterial properties. After being molded through injection processing, the blends were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Impedance Spectroscopy (IS), contact angle, thermogravimetry (TGA), and dynamic mechanical analysis (DMA). FTIR analysis confirmed the presence of PPy chains and the IS results indicated that the blends prepared with a 50% mass fraction of PPy have a conductive character. While the SEM images reveal the presence of small cracks on the surface of the samples, DMA analyses show that a decrease in their mechanical strength occurs in the 50°C-60°C range, with the blend with a 50% PPy load exhibiting the greater resistance and being able to withstand temperatures of the order of 120°C. The TGA degradation profile varies according to the amount of polypyrrole present in the blends, with those containing 50% PPy being able to retain about 32% of the polypyrrole mass at 600°C. The antibacterial activity tests done with the injected blends reveal that while no inhibition halo was formed for the Escherichia coli bacterium, the growth of Staphylococcus aureus is inhibited in the 50% PPy blend.

Keywords:
Polypyrrole; Polylactic acid; Extrusion; Injection; Antibacterial activity