A Case Study of Recycled Poly(Lactic Acid) Contaminated with Petroleum-Based Thermoplastics Used in Packaging Application

摘要

This study was designed to evaluate properties of poly(lactic acid) (PLA) under the postulation that recycled PLA (rPLA) was contaminated with commodity thermoplastics during a typical density-based sorting. Change in clarity, mechanical, and thermal properties of the contaminated rPLA specimens were compared. Clarity of rPLA was reduced showing pale brownish tint when passing multiple processing. Contamination with either PP or HIPS just 1 phr caused rPLA to become opaque, which the transmittance percentage was decreased with respect to contamination content. Compared to pure PLA, the moduli of rPLA was reduced 2.6%. The moduli of rPLA was reduced 4.5-8.2% when contaminated with PP of 1-8 phr, and the moduli was reduced 1.4-4.1% when contaminated with HIPS of 1-8 phr. Elongation at break of PP-contaminated rPLA specimens was reduced with slight increase of impact strength. Elongation at break of HIPS-contaminated rPLA specimens was higher with higher HIPS content, and the impact strength was enhanced up to 64%.