Biodegradable polypyrrole/dextrin conductive nanocomposite: Synthesis, characterization, antioxidant and antibacterial activity

Combination of a natural biodegradable polymer with a synthetic polymer offers excellent capability in advanced functional materials. For this purpose, biodegradable conductive nanocomposites based on polypyrrole/dextrin have been synthesized by in situ polymerization of pyrrole in the presence of dextrin activated in acidic medium. The nanocomposites were characterized by Fourier transform infrared (FT-IR), Ultraviolet-visible (UV-vis), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and field emission scanning electronic microscopy (FESEM). The conductivity of nanocomposites was investigated by four probe method. The prepared nanocomposites were analyzed for antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl assay (DRPH). Our results demonstrated that the conductivity and antioxidant activity of nanocomposites were increased by increasing the amount of polypyrrole in nanocomposite matrix. The nanocomposites were analyzed for antibacterial activity against Gram-positive and Gram-negative bacteria. The results indicated that the nanocomposites are effective against all of studied bacteria and nanocomposite 1 effectiveness is higher for Pseudomonas aeruginosa while nanocomposite 2 is effective against Staphylococcus aureus. In addition, in vitro biodegradability study of the polypyrrole/dextrin composites with different weight ratio was investigated in soil burial degradation. The result demonstrated that the composites are biodegradable under natural environment in range of 30.18-74.52% degradation. The observed physical properties of the polypyrrole/dextrin nanocomposites open interesting possibilities for novel applications of electrically conducting polysaccharide-based composites, particularly those that may exploit the antimicrobial nature of the polypyrrole/dextrin nanocomposites. (C) 2013 Elsevier B.V. All rights reserved.