Synergistic effects of bio-plasticizer and core–shell rubber on poly(lactic acid) toughness for sustainable flexible packaging applications

Abstract

Poly(lactic acid) (PLA) toughness was improved by blending with tributyrin (TBR) and poly(methyl methacrylate-co-ethyl acrylate) core–shell rubber (CSR) for toughening purpose. PLA was prepared by melt processing as binary (PLA/TBR or PLA/CSR) and ternary (PLA/TBR/CSR) blends with the total additive contents from 5 to 20 wt%. Ratios of TBR:CSR for the ternary blend were 25:75, 50:50, and 75:25. Based on the experimental results, a suitable formulation for the flexible packaging application was the addition of 5 wt% TBR and 15 wt% CSR. This formulation exhibited the values of strain at break and impact strength of 512% and 862 J/m, respectively. These values were comparable with those observed in low-density polyethylene (LDPE). Thermal test results indicated some significant changes of the transition temperatures and crystallization behavior which reflected the strong influences of rubbery functions and plasticizing properties of CSR and TBR. Migration test of TBR indicated that the migration rate increased with the test duration. Moreover, samples tested at 100°C exhibited larger amount of migrated TBR than that observed at 50°C. © 2021 Wiley Periodicals LLC.