Pros And Cons Of Polyactic Acid

Polyactic Acid

Is plastic bad for the earth? We use plastic to create items that make our lives easier everyday. Plastic has been molded into bottles, chairs, toys, and almost anything one can imagine. Over time the items created can potentially be more harmful for the planet than helpful. Plastic cannot just disappear, and everyday millions of plastic items are being used, a lot for only one day before being thrown out. It harms our wildlife, pollutes our oceans, and has been shown to be linked to cancer, birth defects, and immune deformations. Every year billions of tons of plastic trash are piled up around the world in landfills or are littered throughout. So why is plastic still used despite all these negative effects? The biggest reason

The main component of PLA is corn starch, which is much more resourceful than oil because it can be regrown. The oil supply will eventually run out, and is not a renewable resource like corn starch. PLA is currently used for only a few different applications such as food containers, cups, packaging, and other items. The United States spends hundreds of billions of dollars on oil each year, and producing corn starch is much easier. The polymer degrades into water, carbon dioxide, and organic materials. PLA is a thermoplastic material, which means it will become a liquid at its melting point. This allows the polymer to be injection molded and can be recycled. The process to produce PLA begins with converting corn to corn sugar. This is done by wet milling, which mainly separates the starch from the corn kennel. The starch is the heated, usually with acid or enzymes, to hydrolyze the starch to dextrose. The dextrose is then isolated and converted to lactic acid. This process usually creates a low density PLA. High density PLA is created by heating the lactic acid with an acid catalyst to create a cyclic lactide. This undergoes a ring-opening polymerization to form high density polyactic acid. There is still research being done on how to create cheap and eco friendly

A large issue with PLA is the fact that large fields of crops are required to produced corn starch. The major controversy is that those crops can be sold as food rather than plastic products. Regular plastics do not require the amount of area and time as PLA. Another thing that makes PLA difficult is that it cannot break down on its own. It must be sent to a compositing factory to be properly broken down. This was a major problem because there was a limited number of these facilities to properly dispose of these items. PLA also has some very good mechanical properties such as good appearance, high mechanical strength, and low toxicity. Tensile and flexural tests were run for PLA, HDPE, Polypropylene, and Polystyrene, and it turns out that PLA had the highest value of all of these different polymers.This means that the material has very high resistance to wear and tear over time. In an Izod impact test, the material actually had the lowest of these polymers, which means that PLA has a very low impact strength. For food packaging polymers, an important factor is their ability to resist transfer of gases, water vapor, and aroma molecules. This is also referred to as permeation, which is not a strong area of PLA. This is due to higher crystallinity of biaxially oriented PLA film. PLA can be recycled back into lactic acid and can be used to make materials of the same quality as before. PLA cannot