It would be difficult to put a number to what portion of all molecules in the world are polymers. Also, you would get a very different number if you calculated a percentage by weight, number, or volume. At the core of your question though is what things are made of polymers. The most concise answer is that polymers are the result of life. Organisms are comprised of 4 main polymers: nucleic acids like DNA, proteins, carbohydrates, and lipids (fats). One of the most important properties of life is the ability to combine small molecules into larger molecules which is the process of polymerization. Organisms need larger molecules such as polymers to store energy and information as well as build structures. The smartest organisms (us) were able to figure out how to make polymers without using living organisms which is how plastics are made. Prior to the invention of plastics and other man-made polymers, all polymers were either part of living organisms or the result of dead organisms. An example would be oil which is the result of long-dead plankton and algae. So before life existed, a very small percentage of things were made of polymers and up to around 1900 all of the polymers were naturally from life. But in the modern era, many things that surround us are made of polymers with the invention of plastics.

I’m not sure I can give you an accurate percentage (it depends on the things around you), but as I’m looking around my office it seems like there are quite a lot of polymers here! An important differentiation is whether or not they’re synthetic or natural polymers. For instance, hair is made of a protein called keratin, which is a polymer, so you’ve technically have polymers growing out of your head. Proteins are polymers that are made of amino acids, and they’re everywhere! DNA, collagen, silk, wool, and cellulose (i.e. cotton) are all polymers- so you’re probably wearing polymers right now. Starch is a polymer of glucose, so if you’re eating cereal for breakfast, you’re getting some polymers in your diet (and hopefully some protein too).

Synthetic polymers are mostly derived from petroleum oil (while some “bioplastics” are made from agricultural sources) and are made by scientists. About 80% of the organic chemical industry is devoted to the production of synthetic polymers. You will probably recognize them as plastics, textile fibers and synthetic rubbers. You may be surprised by all of the places you can find them. Roughly 30-40% of a PC is made of polymers, and this number may be increasing with the application of “organic electronics” in our devices. For example, the Samsung Galaxy S6 uses a OLED (organic light emitting diode) for the backlighting, which is made of polymers. There are polymers added to a lot of materials that we use everyday (or at least pretty often), like in paints, epoxy/glues, furniture, and even in toothpaste! A lot of cosmetics and lotions contain polymers, like nail polish and sunscreen. Polymers are also a very important component to many pharmaceuticals.

Polymers are ubiquitous to everyday life!