Comparison of Novel Conductive Open- and Closed-Porous PPy-PLA Composites

This study compared the fabrication techniques and characterization of novel open- and closed-porous structures in PPy-PLA conductive composites. For the open-porous composites, PLA samples were fabricated using compression molding and salt leaching with varying salt-to-polymer mass ratios, which were subsequently coated with PPy by in situ polymerization of pyrrole and iron (III) chloride. For the closed-porous composites, a patterned structure of PPy within PLA was created using compression molding of PPy-coated PLA pellets, followed by gas saturation and foaming techniques in order to create the closed pores. Characterization of both porous composites included their physical, mechanical, and electrical properties. Results showed that the modulus increased with increasing relative density and decreasing open porosity. The open-porous composites had lower relative density values but higher open porosities compared to the closed-porous composites. The average size of the closed pores was approximately an order of magnitude larger than the open pores. Lastly, the open-porous composites had higher conductivity values than the closed-porous composites due to the greater surface area of the continuous conductive pathway. The comparisons between open- and closed-porous composites established their characteristic properties for their future development in applications.