Monomers are molecules that usually contain carbon or hydrogen and are made up of another element such as oxygen or nitrogen. Polymers are long strings of these monomers. All plastics are polymers. Common types of plastic polymers include polypropylene, polystyrene and poly vinyl chloride, commonly known as PVC.
Polyethylene is perhaps the most common of thermoplastics. It is found in grocery bags, plastic bottles, toys and even as a replacement for Kevlar vests. Polyethylene is a long chain of carbon atoms with two hydrogen molecules attached to each carbon. LDPE refers to low-density polyethylene where carbon atoms have polyethylene chains attached instead of hydrogen atoms, making them extremely strong.
Polypropylene can be more versatile than polyethylene because it has a higher melting point. Because it doesn't melt below 160 degrees Celsius, it is used in food storage units and is safe to use in a microwave and dishwasher, unlike polyethylene, which will melt at 100 degrees Celsius. Polypropylene is also manufactured into fibers, common among miniature golf course turf and outdoor carpeting.
Polystyrene can be found in model cars and airplanes, and packaging foam and insulation. The brand name foam Styrofoam is a type of polystyrene. Plastic drinking cups and plates used for picnics are also made of polystyrene. Knobs, dials and the plastic housings of certain appliance are likely to be polystyrene. SBS, or poly(styrene-butadiene-styrene) is a type of hard, thermoplastic rubber that uses polystyrene as a key ingredient.
PVC is poly vinyl chloride, a plastic common to pipes. PVC pipes can be found everywhere, in most houses, excluding older homes, and commercial buildings. PVC is most useful because of its resistance to water and fire. Raincoats and shower curtains are made of PVC.