Welcome to LETZero Encyclopedia, an introductory series to LG Chem’s eco-friendly brand LETZero and their products. Following the previous episode on PCR PP, an eco-friendly material derived from recycled plastic raw materials, today you will get to know PLA which represents LG Chem’s compostable products, how it is made, and where it is used.

PLA’s raw materials acquired from natural resources

How is PLA (Polylactic Acid) made so that it breaks down and returns to soil? First, extract glucose from corn and sugarcane which are then fermented to create lactic acid. Next, convert the lactic acid into a ring-shaped lactide. The final process is synthesizing the lactide to produce PLA. Like this, you can observe a ring-opening reaction in certain monomers with a ring-shaped structure, referred to as the ‘Ring-opening Polymerization (ROP)’ method. ROP is known for its complicated processing and high production cost. Still, it is a widely-used copolymerization method, yielding a high molecular polymer. Various PLA can be produced depending on the different mixture of raw materials and polymerizing process.

The greatest advantage of compostable PLA is eco-friendliness and excellent physical properties. PLA is made of plant-based raw materials from the nature such as corn, sugarcane, leaves, and marine plants which can effectively replace the petrochemical fuels. Not to speak of its carbon reduction effect, PLA is expected to play a key role in overcoming the exhaustion of resources in our future world, as it has an infinite range of raw materials.

PLA has a comparative price advantage over other compostable plastics, and yet it boasts high tensile strength, transparency, and physical•mechanical properties. With physical properties similar to those of commodity plastics, PLA is gaining attention as the potential replacement for traditional, fossil-fuel based plastic materials. On the other hand, current PLA has a limit of low thermal resistance and processability. Researchers are therefore focusing on blending PLA with other polymers, for instance PBAT with high flexibility, to complement its weaknesses.

Furthermore, PLA consists of lactic acid, a type of metabolite found in human body, which means, it is nontoxic and harmless to humans. Even if PLA is absorbed into your body, it is easily broken down and discharged, making it suitable for medical products, especially orthopedics.

Products made of PLA

With physical properties similar to commodity plastics such as PET and PS, PLA suits various purposes. It is harmless to human body, and thereby used in medical plastic products including suture for surgery, prosthetics, and melting threads. Also, it lets heat and air penetrate easily, allowing its use in daily necessities like disposable bags and tableware, packaging materials, and agricultural mulching films.

So far was an introduction to LG Chem’s eco-friendly material, PLA. The next LETZero Encyclopedia will be delivered to you with a story of Bio-Circular Balanced IPA!