Combined compatibilization and plasticization effect of low molecular weight poly(lactic acid) in poly(lactic acid)/poly(3-hydroxybutyrate- co -3-hydroxyvalerate) blends

摘要

Improving overall properties of poly(lactic acid) (PLA) by blending it with another biobased polymer has been astrong field of research over the last years. In this study we demonstrate the synergetic effect of a small amount (between0.1 and 1 wt%) of oligomer-like PLA (oLA) on the thermal, mechanical and gas barrier properties of the widely studiedPLA-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) blends (90–10 wt%). Films of PLA/PHBV/oLA blends wereprepared via single-screw extrusion. oLA being miscible with both PLA and PHBV, its compatibilizing effect was demonstratedby a decrease of the interfacial tension, a slight shift in the Tgs of both polymers, and an increase in the elongation atbreak. It was also showed that oLA had a plasticizing effect on the PHBV dispersed phase, increasing its crystallinity rate.This resulted in a decrease in the permeability of the films while improving Young’s modulus.