The effects of plasticizer on the mechanical and electrical characteristics of PLA

Polylactic acid (PLA), a biodegradable plastic, has excellent electrical insulation properties. Being a hard resin, however, PLA is difficult to apply to coated cable. In this study, we blended a plasticizer with PLA to soften it, and examined the effects of the plasticizer on the mechanical and electrical characteristics of PLA. The glass transition temperature (T
_g
) and the melting point (T
_m
) had a tendency to decrease with an increase in the amount of plasticizer. With an increase in the amount of plasticizer, the tensile strength had a tendency to decrease and the breaking elongation to increase. As described above, PLA became softer with an increase in the amount of plasticizer. At 298 K, dielectric breakdown strength (E
_B
) was about 5 MV/cm, irrespective of the presence of the plasticizer; the plasticizer showed almost no effect on E
_B
. At 353 K, however, E
_B
had a tendency to increase with an increase in the amount of plasticizer.