Engineered Poly(Lactic Acid)-Talc Biocomposites for Melt Processing: Effects of Co-Blending with Poly(Butylene Succinate) and Poly(Butylene Terephthalate) on Thermal and Mechanical Behavior

This article deals with the design and manufacturing of a novel class of PLA-based material specifically engineered for injection molding, suitable for food contact and characterized by a good balance of mechanical properties and thermal resistance. A commercial PLA grade was modified by blending it with microlamellar talc as reinforcing filler, poly(butylene succinate) (PBS), and poly(butylene terephthalate) (PBT) as secondary polymeric phases. Ternary blend/talc biocomposites were achieved. The different constituents of the biocomposites were compatibilized by reactive compounding extrusion using maleic anhydride (MAH) grafted PLA (PLA-MA). The thermal properties of the compounds prior and after injection molding were characterized by differential scanning calorimetry. The mechanical response of the injection molded materials was evaluated by flat indentation and flexural tests. The mechanical properties of the PLA/talc-based biocomposites and crystallinity of PLA can be controlled by fine tuning the blend by the addition of PBS and PBT in the formulation. In particular, biocomposites characterized by good strength and toughness can be obtained by injection molding, without affecting thermal stability. Based on the experimental findings, the PLA-based formulations pose; therefore, solid bases for replacing oil-based plastics in several markets, specifically in the segment of food and pharmaceutical packaging. POLYM. ENG. SCI., 59:264-273, 2019. (c) 2018 Society of Plastics Engineers