What do DNA and plastic have in common?
It seems unbelievable they would have anything in common. But what might seem even more unreal is, at a molecular level, plastic and DNA are fundamentally similar. They are both types of polymers.
Polymers are substances made from monomers. Monomers are small molecules, able to form chemical bonds with other molecules. When bonded with other molecules they form a chain, becoming macromolecules—the foundation of polymers.
Nature abounds with organic, carbon-based, polymers. They form the very fabric of the natural world. For instance, they compose the solid parts of plants and the amino acids that make protein. The starches we eat are another type of polymer made from glucose. And, yes, even our DNA is a type of polymer, known as a biopolymer.
Though natural polymers are everywhere, so are synthetic polymers. And they play a huge role in the modern world.
Synthetic polymers are created by the polymerization process. The process causes monomers to react and bond together to form a polymer. Because of these synthetic polymers, we are able to enjoy many modern conveniences.
Here we will look at some of the modern, polymer-based products we enjoy and the specific polymers that create them.
Bottles and Packaging
One of the most prevalent uses of polymers is the use of plastic bottles. It’s also used to make other packaging material like clear plastic wrap and even shopping bags. These products are made from the polymer called polyethylene. Polyethylene is a resin made from the polymerization of ethylene. It’s light and easy to use in a variety of applications. In fact, its first use was as insulation for radar cables during WWII.
To polymerize ethylene, the double bond connecting its two methylene units is broken. A single bond results that allows the ethylene molecule to connect with another ethylene molecule. A macromolecule forms when this simple structure is repeated thousands of times in one molecule.
In chemistry, one small change can make all the difference. And there’s no better example than in the production of PVC.
When working with ethylene, replacing one hydrogen atom with a chlorine atom would produce vinyl chloride. When polymerized, vinyl chloride becomes polyvinyl chloride, better known as PVC. You can find this polymer at the hardware store sold as pipes, like the ones used for lawn sprinkler systems.
Textiles and Microwaveable Plastics
The next time you microwave a plastic container or climb into your yoga pants you can thank polypropylene. Harder than polyethylene and unbelievably durable, polypropylene is used in nearly every market sector. It has a remarkably high melting point and can handle a lot of stress without cracking. It also holds up in water and detergents, making it a great choice for textiles that require plastic.
Much like ethylene, the polymerization of propylene involves breaking its double bond. The extra single bond allows individual propylene molecules to link together forming the polymer.
Disposable Cups and Plates
One look at the name of this polymer and you’ll likely know its main use. Polystyrene is largely used to make styrofoam. But it can also be used to make other plastic products as well.
Before polymerization can begin, styrene must be created. Ethylene is reacted with benzene in the presence of aluminum chloride. This creates the compound ethylbenzene. The benzene in the compound is dehydrogenated, creating phenylethylene otherwise known as styrene.
Interestingly, polystyrene is frequently blended with other polymers in a process called copolymerization. This creates a harder end product in plastics and rubbers.
From the protective coating on our cooking tools to our car windshields, silicone is used in a wide array of applications. But you may not have known that it is in fact a polymer. Silicone is also known as polysiloxanes.
Silicone represents a unique class of polymers. They are mixed organic-inorganic compounds. Organic compounds contain carbon. But inorganic compounds do not. Silicone is made by alternating silicon and oxygen atoms with organic compounds which are usually either vinyl, methyl or phenyl. Silicones with low molecular weight are sold as oils and greases. But some silicones are solid and have a higher molecular weight. They stay rubbery at low temperatures and stable at high temperatures. This makes them perfect for coating kitchen tools.
Synthetic polymers have become a staple in the production of the products we use daily. Still, chemists continue to push the boundaries of what is possible in polymers. With the growing concern for plastic waste on our planet, chemists are working on polymers that have more biodegradable properties. As chemists develop the products of our future, they rely on quality chemicals like those produced by Noah Technologies.
Noah Technologies has been a leader in the chemical industry for over forty years and supplies specialty chemicals to countless industries and for various applications. Contact us for your chemical needs whether you have a new product that you are looking to introduce into a new or old application or a rare or unique product with special parameters. Custom chemicals is our niche—and we have chemists on staff to assist you.