> Materials Science : Plastics Quiz
Materials Science : Plastics Quiz
A plastic is any of a wide range of synthetic or semi-synthetic moldable organic solids. Plastics are organic polymers that often contain other substances. They are usually synthetic and commonly derived from petrochemicals, but many are in some measure natural. The majority of these polymers are based on chains of carbon atoms or carbon atoms with oxygen, sulfur, or nitrogen atoms as well. The backbone is a chain of monomers. There are so many plastics available for use because there are so many different monomer combinations. To customize a plastic, different molecular groups called side chains, are attached to the backbone. The structures of the side chains influence the properties of the polymer.
Plastics are usually classified by their chemical structure of the polymer's backbone and side chains. Some important groups in these classifications are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. There are two types of plastics: thermoplastics and thermosetting polymers.
Thermoplastics do not undergo chemical change in their composition when heated and can be molded again and again. Examples of thermoplastics include polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polytetrafluoroethylene. Thermosets can take shape once, and after they have solidified they retain their shape. In the thermosetting process, the chemical reaction that occurs is irreversible. Examples of thermosets are polyurethane, polyester and epoxy resins. The vulcanization of rubber is a thermosetting process.
There are seven distinct kinds of plastics, based on their ability to be recycled:
1. Polyethylene terephtalate
2. High density polyethylene
4. Low density polyethylene
For the following quiz, review the above summary to assist you in answering the question. Select the best choice from the given answers.
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