How is plastic made?
The technological road from oil field to finished plastic product has numerous fascinating side trips. Here’s the route taken in the petroleum-to-plastics process: 1. Petroleum is drilled and transported to a refinery. 2. Crude oil and natural gas are refined into ethane, propane, hundreds of other petrochemical products and, of course, fuel for your car. 3. Ethane and propane are “cracked” into ethylene and propylene, using high-temperature furnaces. 4. Catalyst is combined with ethylene or propylene in a reactor, resulting in “fluff,” a powdered material (polymer) resembling laundry detergent. 5. Fluff is combined with additives in a continuous blender. 6. Polymer is fed to an extruder where it is melted. 7. Melted plastic is cooled then fed to a pelletizer that cuts the product into small pellets. 8. Pellets are shipped to customers. 9. Customers manufacture plastic products by using processes such as extrusion, injection molding, blow molding, etc. Sources:
J.Z. Northbrook, Ill. A. There are all kinds of plastics. But they have one thing in common. They’re all made of very, very long molecules, called polymers. Polymers are nothing more than long chains of identical repeating units, called monomers, which are just small molecules. “Think of polymers as a string of pearls,” says Michael Rubner, professor of polymer materials science and engineering at MIT. “They’re incredibly simple, but beautiful.” Rubner says it’s their amazing length, hundreds of thousands of units long, that gives plastics their unique properties of flexibility and strength. The trick to making polymers is getting the individual monomers to link up. It’s kind of like performing magic on a big box full of paper clips so they end up in one giant paper clip chain, all connected. The monomers in plastic are molecules made up mostly of atoms of carbon, oxygen, hydrogen, and nitrogen. Atoms bond together in different ways, depending on how many electrons each has, and wh
The Basics of Plastic Manufacturing The Structure of Polymers Additives The Two Plastic Types, Based on Processing Thermoplastic and Thermoset Processing Methods The Basics of Plastic Manufacturing The term plastics includes materials composed of various elements such as carbon, hydrogen, oxygen, nitrogen, chlorine, and sulfur. Plastics typically have high molecular weight, meaning each molecule can have thousands of atoms bound together. Naturally occurring materials, such as wood, horn and rosin, are also composed of molecules of high molecular weight. The manufactured or synthetic plastics are often designed to mimic the properties of natural materials. Plastics, also called polymers, are produced by the conversion of natural products or by the synthesis from primary chemicals generally coming from oil, natural gas, or coal. Most plastics are based on the carbon atom. Silicones, which are based on the silicon atom, are an exception. The carbon atom can link to other atoms with up to
Plastic is one form of polymers that are composed of a long chain or line of smaller molecules that are known as monomers. Monomers themselves are made of atoms that are usually extracted from natural or organic substances, and are generally classified as petrochemicals. All sorts of monomers can be utilized in the creation of plastic. Crude oil and natural gas are often the source of some of these elements, which include monomers such as styrene, vinyl chloride, and vinyl acetate. Polymers are created by forming a series of chains or strings of monomers. Processing the polymers in one of two methods results in the formation of plastic. With the thermosetting method, liquid monomers are poured into a mold and allowed to cool. The liquefied monomers are permanent in shape, producing durable goods. With the thermoplastic approach, the liquid monomers are heated and slowly molded into shape. After the heating and manipulation into the desired shape, the product is cooled and allowed to se
Plastic bottles, plastic bags? elliot r barenbaum Answer: Well, I looked this up in the “McGraw-Hill Concise Encyclopedia of Science and Technology.” (second ed., 1981). Plastics are relatively stiff materials made of polymers (long molecules made of smaller molecular units joined together) and other ingredients such as fillers, pigments (for color), plasticizers, flow improvers, and stabilizers. The polymers are made by finding small molecules which will chemically bond together at at least two places in each small molecule (these are called “active sites”). There are two basic mechanisms for forming chains out of the smaller molecules, but I won’t get into that (unless you ask me to). Anyway, let’s say you have some plastic and you now want to shape it into a bottle or something. There are a number of processes, and you use whichever process leads to the kind of shape, thickness, and utility you need for your job. One way to go is “thermomolding,” in which you form plastic sheets int
