Polymers form through covalent polymerization, connecting small monomer units into macromolecular chains.

At the heart of every polymer is a simple chemical reaction. Small, active molecules called monomers collide and hook together. They share electrons to form incredibly strong covalent bonds. This process repeats thousands of times, creating a single molecule of immense length. It is like snapping together plastic toy bricks, but on an atomic scale. These chains can be completely straight, or they can sprout branches like trees. The length of these chains is staggering. While a water molecule contains just three atoms, a single polymer chain can easily contain hundreds of thousands. This vast size gives them physical properties that smaller molecules can never achieve.