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How do covalent bonds hold the atoms in a polymer chain together?

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Diagram illustrating a homopolymer arrangement using polyvinyl chloride as an example, showing a chain of identical repeating vinyl chloride units with the chemical structure highlighted. — polymer Industrial polymers are synthesized from simple compounds joined together to form long chains. For example, polyvinyl chloride is an industrial homopolymer synthesized from repeating units of vinyl chloride.

In a polymer, the atoms that form the long, chainlike molecules are held together by covalent chemical bonds. These bonds are created through the sharing of electrons between atoms.12

During the process of polymerization, relatively small molecules known as monomers combine chemically to form these large structures, often referred to as macromolecules. The formation of these stable covalent bonds is what distinguishes polymers from substances where molecules are merely held together by weaker intermolecular forces, such as those found in crystallization.12

While covalent bonds provide the strong internal structure of the polymer chain, individual polymer molecules also interact with one another through electrostatic forces. Although these electrostatic forces are significantly weaker than covalent bonds, they become increasingly important as the size of the polymer molecules grows, contributing to the material's physical properties, such as its ability to be molded or drawn into fibers.2