Evaluating the Efficacy of a Unique “New to the World” Amorphous PHA to Modify PLA for Flexible Packaging Applications

ABSTRACT Bio‐based compostable plastics are increasingly being explored as alternatives to petro‐chemical plastics, but polylactide (PLA)'s inherent brittleness limits its use in flexible packaging. This study evaluated an amorphous polyhydroxyalkanoate (A1000P) as a toughening modifier for PLA in blown and co‐extruded films. Blending 25–30 wt% A1000P into PLA (grades CA1270P and CA1240PF) reduced tensile modulus by 68%–85% relative to neat PLA while increasing elongation at break from negligible values to over 400% (MD) and 300% (TD). Dart impact resistance, unmeasurable for brittle neat PLA, increased substantially in the A1000P‐modified blends, with CA1240PF showing the greatest toughness among the compositions tested. A tri‐layer (A/B/A) co‐extruded film using CA1240PF skins and an A1000P‐rich core combined the mechanical benefits of the A1000P‐modified skins with an A1000P‐rich core, increasing dart impact resistance by approximately 20% relative to a CA1240PF control. Incorporating A1000P also accelerates industrial compostability, reducing the time to complete PLA mineralization by approximately 25–30 days. These results demonstrate that A1000P is an effective, bio‐based and compostable toughening agent for PLA, enabling flexible‐film properties competitive with a commercial non‐biobased compostable benchmark (Ecovio F2224) while also accelerating the industrial composting of PLA.