Despite its name, Polylactic Acid is in the family of polyesters, composed of two main monomers: lactic acid and the cyclic di-ester, lactide. Widely known as PLA plastic, it is the second most commonly used bioplastic in the world. Formulated with specific attention to the environment, PLA plastic is derived from cornstarch or sugarcane and is designed to degrade back to its constituent components for a relatively benign environmental impact. As a biologically derived polymer, it is highly workable, and useful in situations where gradual dissolution is desirable. PLA plastic is often used for temporary fittings fasteners, plates, and other mechanical parts for the medical industry, and its biodegradable properties also make it useful for food packaging. The proliferation of its use in all types of industries is an indication of its effectiveness.
As a low-temperature plastic, polylactic acid has a relatively lower melt point than high-performance plastics, and more research into the possibilities of increased temperature resistance is ongoing. In many respects, however, PLA plastic performs well in its dimensional stability and it can be crystallized to achieve more rigidity. While not designed for long life or high temperatures, the low cost and sustainability, combined with its ease of use, contribute to PLA plastic’s popularity.