Electrical properties of polylactic acid with nucleating agent added

We examined the electrical properties of polylactic acid (PLA) with a nucleating agent added. The PLA with added nucleating agent was then heat‐treated at 100 °C for 30 seconds. The crystallinity of the PLA with added nucleating agent increased to more than 40%, and its crystallization speed also increased significantly. The temperature dependence of the conductivity (σ) was investigated; at temperatures higher than 60 °C, σ of PLA to which the nucleating agent had been added showed a tendency to become lower than σ of PLA to which no nucleating agent had been added. The temperature dependence of the dielectric breakdown strength ( $E_B$ ) was investigated. $E_B$ of the PLA with added nucleating agent was about 5.0 MV/cm at 25 °C. Of particular note was the fact that the $E_B$ of PLA with added nucleating agent was about 4.7 MV/cm at 100 °C, which is about 3 times the $E_B$ value for PLA with no added nucleating agent. The temperature dependence of the relative dielectric constant (ϵ r ″ ) and the relative dielectric loss factor (ϵ r ″ ) was investigated. The peak dielectric absorption value of ϵ r ″ for the PLA to which nucleating agent had been added showed a tendency to be lower than that of the PLA to which no nucleating agent had been added. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(3): 25–31, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21293