Electrical properties of polylactides

A PLA film with low crystalline-phase content was investigated in a DC field within the temperature range of 25-70 degrees C. The polymer exhibits low electrical conduction with increasing activation energy within the area of the glass transition temperature. Electrets were made from the PLA film precursor using an isothermal polarization method. The charge on the electrets was assessed by measuring the field intensity. The surface charge of an electret has the character of a hetero-charge. After 4 months from termining the isothermal charging and cooling, the PLA film polarized at E-p > 16.7 MV/m was affirmed the applicable electret properties. (C) 2013 Elsevier B.V. All rights reserved.