Mechanical and Electrical Properties of Polylactic Acid with Aliphatic-Aromatic Polyester

Abstract

Assuming an application where polylactic acid (PLA), a hard bioplastic, is used to sheath electrical wire, the author added 20 wt% of aliphatic-aromatic polyester or polybutyrate adipate terephthalate (PBAT), a soft resin, to PLA and then investigated the softened PLA’s mechanical and electrical properties. As a result of adding PBAT to PLA, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:msub><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mrow><mml:mi>g</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math> shifted to about 10°C lower than PLA. In addition, adding PBAT to PLA made the PLA softer and even more so at temperatures above 40°C. Furthermore, adding PBAT to PLA decreased the electric breakdown strength (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:msub><mml:mrow><mml:mi>E</mml:mi></mml:mrow><mml:mrow><mml:mi>B</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>) of the PLA by about 1 MV/cm over the temperature range of 0°C to 50°C, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mrow><mml:msub><mml:mrow><mml:mi>E</mml:mi></mml:mrow><mml:mrow><mml:mi>B</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math> was slightly higher than that of PVC over the temperature range of −10 to 60°C.