Polymers: big molecules made from repeating units.

Polymers (plastics) have a zillion uses.

Question: Why are polymers so useful and versatile? 

Answers:

• Many types of polymers exist
• Each type has some useful properties, such as mechanical strength, flexibility, electrical insulation, chemical resistance, or optical clarity.
• Polymer recipes can be customized to get just the right mix of properties for almost any product
• Polymers can be mass produced to make products less expensive than things made from metals, ceramics, or organic materials such as wood
• Polymers are generally lightweight and strong for their weight.

Example Polymer: Polypropylene

Polypropylene is a type of plastic. Lots of products are made from polypropylene. Here are a few examples:

Polypropylene is made by combining lots of propylene molecules.(propylene is the same thing as propene)

Those structures both show the same molecule, but a bent version of polypropylene can help to show how lots of these molecules can chain together:

The polymer version loses the double bonds and connects to other molecules. Here is a section of polypropylene molecule made of four units:

The dots are meant to indicate that the pattern could go on forever in both directions. A typical polypropylene molecule is thousands of units long.

Important Polymers in Consumer Products:

Polyethylene (“HDPE” and “LDPE”): simplest type of plastic – milk jugs, yogurt containers, shopping bags, and a zillion other products are made of this.

Polycarbonate: bullet resistant “glass,” eyeglass lenses

Polyvinyl Acetate (PVC): PVC pipe, shoes

Polyethylene Terephthalate (PET): pop bottles

Polystyrene (PS): Solo cups, styrofoam

Important Polymers in Living Things:

DNA is a polymer made of phosphate, ribose (a sugar) and nucleic acids.

Starch is a polymer made of sugars.

Protein is a polymer made of amino acids.