By Allison Tang
Polymer synthesis is the procedure through which long-chain
macromolecules—polymers—are assembled from small monomer building blocks. As outlined
in Vollhardt & Schore’s Organic Chemistry (2018), polymers are largely produced by addition
polymerization of alkenes, where monomer units are successively added, converting double
bonds into single-bonded backbones. This procedure of molecular assembly forms the basis for
most everyday materials, such as high-strength fibers and biomedical devices.
There are two main methods of polymer synthesis: step-growth polymerization and chain-growth
polymerization (addition polymerization) (Reimschuessel, 1975). Chain-growth polymerization
is initiated by a reactive species that activates a monomer. Once activated, new monomers add to
the propagating chain rapidly, one by one. Chain-growth polymerization is widely used for
synthesizing commercially important plastics like polyethylene and polystyrene (National
Polymer, 2024). The efficiency of chain-growth polymerization makes it an excellent choice for
synthesizing polymers with very high molecular weights (Reimschuessel, 1975).
Step-growth polymerization (condensation polymerization) employs monomers with two or
more reactive groups—such as diols, diamines, and diacids—that build up in a series of steps.
Each reaction typically releases a small by-product like water or HCl. Unlike chain-growth, step-
growth polymerization does not require an initiator but relies on the functional groups present on
the monomers. Step-growth polymerization is commonly used in the preparation of nylons,
polyesters, and epoxy resins (Sigma-Aldrich, n.d.).