How is Plant Based Plastic Made?A corn field against a blue sky. PLA plastic is made primarily from corn.

How is Plant Based Plastic Made?

What is PLA Plastic?

PLA, or Polylactic Acid, is a type of biodegradable plastic derived from renewable resources such as corn starch, tapioca roots, or sugar cane. Unlike traditional plastics, which are derived from petroleum, PLA is considered more sustainable and environmentally friendly.

PLA has become particularly popular in 3D printing, where it's valued for its ease of use and relatively low print temperature, as well as its environmental benefits. It is also becoming increasingly popular in creating straws, plastic forks, spoons, and knives, as well as takeout containers and packaging. It is also being used for garbage bags, plastic wraps, and in some electronic casings.

How PLA is Made

  1. Raw material processing: The process begins with the raw materials, such as cornstarch. The corn is milled and processed to extract the glucose in the corn kernels.
  2. Fermentation: The glucose is fermented under specific conditions, using bacteria or yeast. This produces lactic acid, a naturally occurring compound.
  3. Polymerization: The lactic acid is then transformed into lactide through a process called condensation. The lactide is a dimer, which is a molecule made up of two smaller molecules that are chemically identical. The lactide is purified and then polymerized (turned into a long chain of repeating units, a polymer) to create polylactic acid (PLA).
  4. Processing into final form: The resulting PLA polymer can then be turned into small pellets, which can be used to make a wide range of plastic products. This is often done by melting the pellets and then extruding, molding, or spinning them into the desired form.

Environmental Benefit to Plant Based Plastic

Polylactic Acid (PLA) offers several environmental benefits compared to traditional petroleum-based plastics:

  • Renewable Raw Materials: Unlike traditional plastics, which are derived from non-renewable petroleum, PLA is made from renewable resources like corn starch or sugar cane.
  • Lower Carbon Footprint: The process of growing the plants that will be turned into PLA absorbs CO2, which can result in a lower carbon footprint compared to conventional plastics, depending on how it is produced and discarded.
  • Biodegradability and Compostability: Under the right industrial conditions, PLA can be composted and biodegraded, unlike many traditional plastics which can take hundreds of years to decompose in the environment.

Environmental Challenges

However, it's important to note that PLA isn't without its environmental challenges. PLA is compostable under industrial conditions and it may not degrade quickly in a backyard compost heap or in the natural environment. As such, while it's a big step forward in the materials we use and the manufacturing process, it's not a complete solution to the problems associated with plastic waste.