How is Plastic Made?

Plastic is a material comprising elements such as carbon, oxygen, hydrogen, chlorine, sulfur and nitrogen. These molecules are held firmly together to form heavy plastic molecules. Also referred to as polymers, these plastics were initially manufactured from naturally occurring materials like horns of animals, shellac (from secretions of minuscule scale insects), gutta-percha (from sap of trees). It was only in 1869 that the first synthetic plastic was prepared from the natural plant material; cellulose. An American printer and inventor called Wesley Hyatt discovered that cellulose nitrate could be plasticized by adding camphor.

The first commercially acclaimed, synthetic plastic material was called celluloid. This plastic found its applications in scores of areas like combs, dentures, eyeglass frames, etc. Plastic storage containers, bins and boxes are widely used to store various liquid and solid products across the globe. The revolutionizing discovery in the field of plastic took place in 1951, when two young research chemists happened to discover polypropylene and polyethylene. This discovery paved the way for myriads of plastic products manufactured and used across the globe. Enough about the story of plastics! Let's head to find out how is plastic made today.

The plastic that has become such an integral part of our daily lives can be prepared from a variety of sources. Let's check out some of the different sources from which plastic is made.

Plastic Made From Petroleum
To prepare plastic from petroleum, the petroleum is first drilled and transported to a refinery. At the refinery, the petroleum is made to go through the refining process along with natural gas to form ethane, propane and scores of other petrochemical products. Next, the ethane and propane formed are further broken down using furnaces with high temperatures to form ethylene and propylene.

In a reactor, the ethylene and propylene formed is combined along with a catalyst to form a powdery substance. This powdery compound formed which bears semblance to washing powder, however, is the polymer. In a continuous blender, some additives are combined with the polymer and then, fed to an extruder, where it enters the molten state.

The molten plastic is allowed to cool and then, fed into a pelletizer, which divides the polymer into tiny pellets. These pellets formed are the ultimate plastics that are shipped across to various customers. Manufacturers of combs, plastic bottles, dentures, plastic utensils, etc. purchase these pellets and then, use it to prepare their products by allowing the pellets to go through different processes like extrusion molding, calendering, film blowing, injection molding and blow molding, rotational molding, casting etc.

Plastic Made From Corn
It's wonderful that plastic can be prepared from petroleum, however, it takes a lot of petroleum to make it. To protect a great resource like petroleum from getting exhausted, various efforts are being taken in USA. In December 2009, an Ithaca, New York based company, Novomer, Inc. announced its commencement of commercializing the company's polypropylene carbonate (PPC) materials by using a combination of carbon dioxide and petroleum. Their effort has been co-funded by New York State Energy Research and Development Authority. The idea is to add carbon dioxide, so as to reduce the need for petroleum by half, which is required for the formation of plastic.

Are you wondering, how is plastic made from corn? Well, a company named Spectragraphics Label Systems has been making labels for over 25 years. They were using the non-renewable resource petroleum to make the plastic required for their labels, however, they came up with a way to make plastic for their labels from the corn we normally consume. They made use of the carbohydrate sugars present in corn to form a type of plastic called polylactide polymers. This plastic manufactured by them bears the trademark, 'NatureWorks'. Quite a remarkable invention, isn't it!

Discovery of corn plastic has reduced our dependency on the exhaustible petroleum. Corn kernels are milled and dextrose is added to it in the milled form, which is then allowed to ferment and produce polylactide polymer (PLA) and lactic acid as by-products. PLA is then created into pellets like that done with the plastic from petroleum. However, if PLA is truly a substitute for plastic from petroleum, then the question arises, 'why hasn't it taken over the plastic industry?' One reason is that corn plastic cannot be heated beyond 114° without melting. This is why PLA cannot overtake traditional plastic made from petroleum to make plastic grocery bags, store hot food, etc.

Besides corn, some other natural resources from which plastic can be made is citrus fruits like oranges, lemons, grapefruits, tangerines, etc. Researchers are still desperately trying to find a compound that can substitute petroleum need to make plastic. Let's hope researchers do find something really soon so that we can stop exhausting the non-renewable resource. Till then, let's continue plastic recycling and use as much as glass instead of plastic as we can! I hope this article about how is plastic made was informative and helpful.