Week 7: Lecture 13 and 14: Polymers and ceramics

Polymers are materials made of long, repeating chains of molecules. The materials have unique properties, depending on the type of molecules being bonded and how they are bonded. Some polymers bend and stretch, like rubber and polyester. Others are hard and tough, like epoxies and glass. Polymers touch almost every aspect of modern life. Chances are most people have been in contact with at least one polymer-containing product from water bottles to gadgets to tires in the last five minutes. The term polymer is often used to describe plastics, which are synthetic polymers. However, natural polymers also exist; rubber and wood, for example, are natural polymers that consist of a simple hydrocarbon, isoprene, according to Encyclopedia Britannica. Proteins are natural polymers made up of amino acids, and nucleic acids (DNA and RNA) are polymers of nucleotides complex molecules composed of nitrogen-containing bases, sugars and phosphoric acid, for example. A polymer can be a three dimensional network (think of the repeating units linked together left and right, front and back, up and down) or two-dimensional network (think of the repeating units linked together left, right, up, and down in a sheet) or a one-dimensional network (think of the repeating units linked left and right in a chain). Each repeating unit is the “-mer” or basic unit with “poly-mer” meaning many repeating units. Repeating units are often made of carbon and hydrogen and sometimes oxygen, nitrogen, sulfur, chlorine, fluorine, phosphorous, and silicon. To make the chain, many links or “-mers” are chemically hooked or polymerized together. Linking countless strips of construction paper together to make paper garlands or hooking together hundreds of paper clips to form chains, or stringing beads helps visualize polymers.

Download Files

polymers.ppt (2.03 MB )