Polylactic acid

Polylactic Acid

Polylactic acid (PLA) is a biodegradable and bioactive thermoplastic polymer derived from renewable resources, such as corn starch or sugarcane. It is a versatile material that has gained significant attention in recent years due to its potential to replace traditional petroleum-based plastics in various applications. PLA is known for its excellent mechanical properties, biocompatibility, and environmental sustainability.

History

The development of PLA can be traced back to the early 20th century when it was first synthesized by Wallace Carothers, a chemist at DuPont. However, it was not until the 1980s that PLA gained commercial significance. In 1992, the first commercial production of PLA began by Cargill Dow LLC, a joint venture between Cargill and Dow Chemical Company.

Production

PLA is produced through a two-step process: fermentation and polymerization. In the fermentation step, starch from corn or sugarcane is converted into lactic acid by the action of bacteria. The lactic acid is then purified and polymerized to form PLA. The polymerization process can be carried out through either condensation or ring-opening polymerization.

Properties

PLA exhibits a range of desirable properties that make it suitable for various applications. It has good mechanical strength, comparable to that of petroleum-based plastics, and can be processed using conventional plastic processing techniques such as injection molding and extrusion. PLA is also transparent, making it suitable for packaging applications. Additionally, it has good barrier properties against oxygen and moisture, which further enhances its potential for food packaging.

Applications

PLA has found applications in various industries, including packaging, textiles, automotive, electronics, and medical. In the packaging industry, PLA is used for producing bottles, trays, films, and other disposable items. In the textile industry, PLA fibers are used to make clothing, upholstery, and non-woven fabrics. In the automotive industry, PLA is used for interior components and as a substitute for petroleum-based plastics. In the medical field, PLA is used for surgical sutures, drug delivery systems, and tissue engineering scaffolds.

Environmental Impact

One of the key advantages of PLA is its environmental sustainability. As a biodegradable polymer, PLA can be broken down by microorganisms into carbon dioxide and water, reducing its impact on the environment. PLA also has a lower carbon footprint compared to petroleum-based plastics, as it is derived from renewable resources. However, it is important to note that PLA requires specific conditions, such as high temperatures and humidity, for efficient biodegradation.

Future Developments

Research and development efforts are ongoing to further improve the properties and performance of PLA. Scientists are working on enhancing its thermal stability, impact resistance, and processability to expand its range of applications. Additionally, efforts are being made to develop cost-effective methods for large-scale production of PLA.

See Also

• Biodegradable plastics
• Renewable resources
• Sustainable materials