Evaluation of Processability and Functional Properties of Low‐Cost Compatibilized <scp>PLA</scp> ‐ <scp>PHBH</scp> Blends for Thermoforming

ABSTRACT Single‐use food trays are widely employed in take‐away and delivery services, contributing substantially to landfill accumulation. Although bioplastic alternatives have been developed, their limited processability and high production costs have hindered large‐scale adoption. To address this challenge, compatibilized blends of polylactic acid (PLA), poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBH), and talc were compounded via twin‐screw extrusion and used to produce thermoformed trays. Talc was introduced at 20 wt% in all formulations. Three different PLA/PHBH ratios were investigated in the polymeric phase: 20/80, 50/50, and 80/20. Talc reduces the overall cost of the formulations while increasing crystallinity and stiffness. The incorporation of a reactive chain extender improves the impact strength of the compounds, counteracting the stiffening effect of talc. In blends with a polymeric phase of 50% PLA and 50% PHBH, the impact strength exceeded 20 kJ/m 2 . Blends with higher PLA content exhibited superior mechanical performance, with a maximum stress of 48 MPa and an elastic modulus of 1.2 GPa. Trays with a polymeric phase containing 80% PLA and 20% PHBH did not fracture in compression up to deformations greater than 80%, offering the best compromise between stiffness and impact resistance and demonstrating strong potential for the cost‐effective production of bio‐based food trays.