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 (Tg) and the melting point (Tm) 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 (EB) was about 5 MV/cm, irrespective of the presence of the plasticizer; the plasticizer showed almost no effect on EB. At 353 K, however, EB had a tendency to increase with an increase in the amount of plasticizer.