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 degrees 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 (sigma) was investigated; at temperatures higher than 60 degrees C, sigma of PLA to which the nucleating agent had been added showed a tendency to become lower than sigma 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 degrees 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 degrees 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 (e '(r)) and the relative dielectric loss factor (e(r)'') was investigated. The peak dielectric absorption value of er gg 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. (C) 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