Polylactic acid (PLA) is a well-known bio-based thermoplastic. This versatile, renewable polymer is a premier example of the commercial success of a bio-based, sustainable material with an established and growing technology base.1 The polymer backbone of PLA is based on renewable carbon produced via the bacterial or yeast fermentation of sugars, derived from annually renewable agricultural sources. The fermentation process produces lactic acid, which is chemically converted to lactide and then polylactic acid via ring opening polymerization. It is used in a variety of applications such as compostable food service-ware and packaging, 3D printing filaments, hygiene products, compostable coffee capsules and tea bags, and nonwovens.2 PLA brings value to these applications beyond a sustainable, low-carbon footprint through performance attributes such as a high modulus, excellent solvent and grease resistance, food contact compliance, and where it can be industrially composted back to CO2 and water. Beyond compostability, PLA can also be both chemically and mechanically recycled into virgin polymer for new applications. These multiple after-use options combined with being made from renewable resources make PLA a leading biomaterial for bringing the concept of the circular economy into practice.
There is a breadth of physical properties that can be achieved by PLA and its compounds that are driven primarily by the control of the PLA molecular weight, degree of crystallinity, melting point and formulation additives. As a testament of the commercial success of PLA, in 2017, NatureWorks’ Blair manufacturing site reached a production milestone of making more than one-million cumulative metric tonnes of Ingeo™ PLA.