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In this page you will find free data about Polylactic Acid, including:
- What is Polylactic Acid
- How to make Polylactic Acid
- Polylactic Acid uses and applications
This page presents brief synopsis of Polylactic Acid production technology, describing, in a concise way, relevant technical and economic aspects. Each manufacturing process description will consist of:
- Major process steps
- Simplified, schematic flow diagram & key equipment
- Important safety or environmental considerations
- Economic perspective, comprising capital expenditures and/or operating expenses
Polylactic Acid Manufacture
Polylactic acid (PLA) is the bio-degradable polymer of lactic acid, which is produced via fermentation processes. For the last five decades, PLA has been mainly used in biomedical applications. The development of economical production routes and a rising environmental awareness by the general public have pushed PLA uses to new markets, including consumer goods and packaging applications.
This simplified flowsheet depicts a process for lactic acid production via glucose fermentation similar to that developed by Purac (now Corbion; Amsterdam, the Netherlands; www.corbion.com). This process generates an 88 wt.% lactic acid solution in water that can be used as the raw material in polymerization processes. Rigorous control of fermentation conditions and additional purification steps are necessary to ensure both optically and chemically pure lactic acid. The quality of the PLA produced from it depends on the purity.
High-molecular-weight PLA can be produced through two main routes: an indirect route via a lactide intermediate, and a direct polymerization by polycondensation. The indirect route is the most common in industry, and is employed by two of the major PLA producers: NatureWorks LLC (Minnetonka, Minn.; www.natureworksllc.com) and Corbion-Purac (Amsterdam, the Netherlands; www.corbion.com).
In the indirect process, lactic acid is first oligomerized and depolymerized to produce lactide, a cyclic dimer of lactic acid. Then, through a ring-opening polymerization, lactide is converted to polylactic acid.
The flowsheet depicts a process for PLA production via a ring-opening polymerization process similar to that developed by NatureWorks. This process can be divided into two main areas: oligomerization and lactide formation; and lactide polymerization. In this process, the optical properties of the lactic acid feedstock are preserved in the polylactic acid.
Oligomerization and Lactide Formation
Lactic acid is fed to the oligomerization reactor, from which water vapor is removed, condensed and sent to a waste-treatment system. The resulting oligomer stream is mixed with catalyst and fed to the depolymerization reactor, which is a packed column operating under vacuum. Water, lactic acid and lactide are ...
The polymer-grade lactide undergoes a ...