Polymers: What are they?

Polymers are large molecules made up of repeating smaller units called monomers. They are a key class of organic compounds and are the basis for many materials we use every day, particularly plastics.

Plastics are made from Polymers

Plastics are a common type of polymer. The word "plastic" itself describes their ability to be shaped or molded. This property arises from the long, chain-like structure of polymer molecules, which can slide past each other when a force is applied.

Key Characteristics of Polymers

• Large molecular mass
• Repeating structural units (monomers)
• Can be natural or synthetic
• Often have low density
• Can be flexible or rigid depending on the type of polymer

Types of Polymers

Polymers can be broadly classified into two main types:

• Natural Polymers: These occur naturally in plants and animals. Examples include starch, cellulose, proteins, and DNA.
• Synthetic Polymers: These are man-made polymers, often produced from petroleum-based chemicals. Examples include polyethylene, PVC, and nylon.

Table: Comparison of Natural and Synthetic Polymers

Feature	Natural Polymers	Synthetic Polymers
Source	Plants and Animals	Man-made (e.g., from petroleum)
Examples	Starch, Cellulose, Proteins, DNA	Polyethylene, PVC, Nylon
Complexity	Often complex structures	Can be designed with specific properties

Understanding that plastics are polymers is fundamental to studying their properties, manufacturing, and environmental impact. The properties of a plastic are largely determined by the type of polymer it is made from and how the polymer chains are arranged.