These values have mean of 17 and standard deviation of about 4.1. If instead we first calculate the range of our data as 25 â 12 = 13, and then divide this number by four we have our estimate of the standard deviation as 13/4 = 3.25.
Thermoset plastics are types of plastics that retain the shapes that they are molded into. In other words, these are hard plastics. They are very durable and most of the time can be used and reused many times. These are the types of plastics that are used in aircraft parts, tires, and many others. The other half of the main types of plastics is thermoplastic.
These chemicals, as well as styrene, are called monomers. The Monomers are chemically bonded into chains called polymers. The properties and characteristics of these polymers vary greatly. Below are the different types of plastics with their properties and common uses. Polypropylene has relatively poor impact strength, but excellent compatibility with weak and concentrated acids, bases and alcohol.* Polypropylene is commonly used to make bottles, vials, pumps, funnels and clothing.