28 March 2017
33 - Your Polymer Glossary

After the Science Lessons series, we bring to you Sumitomo Chemical Asia’s very own Polymer Glossary. This one is a simplified version for the Organic Chemistry beginners and amateurs. Here are some terms, worth remembering along with their IUPAC (International Union of Pure and Applied Chemistry) definitions and footnotes:


Alternating Copolymer – A copolymer consisting of macromolecules comprising two species of monomeric units in alternating sequence. (Read on to know what Copolymers and Macromolecules are.)


Branch – An oligomeric or polymeric offshoot from a macromolecular chain.

Branch Chain – A chain with at least one branch point intermediate between the boundary units (i.e. the end-groups or other branch points).

Branched Polymer – A polymer in which the molecules are branched chains.


Chain – The whole part of part of a macromolecule (or oligomer molecule or block) comprising a sequence of constitutional units between two boundary constitutional units, each of which may be either an end-group or a branch point.

Chain Polymerization – A chain reaction in which the growth of a polymer chain proceeds exclusively by reaction(s) between monomer(s) and reactive site(s) on the polymer chain such that the reactive site(s) are regenerated on the same polymer chain by the end of each growth step. A chain polymerization consists of initiation and propagation reactions, and may also include termination and chain transfer reactions.

Constitutional Unit – An atom or group of atoms in a macromolecule or oligomer molecule, comprising a part of the chain together with its pendant atoms or groups of atoms, if any.

Co oligomer – An oligomer derived from more than one species of monomer.

Copolymer – A polymer derived from more than one species of monomer.
A point to note is that copolymers which are obtained by copolymerization of two monomer species are sometimes termed as bipolymer, those obtained from three monomers are terpolymer and those obtained from four monomers are quaterpolymers, etc.

Copolymerization – Polymerization reaction in which a copolymer is formed.

Crosslink – A small region in a macromolecule from which at least four chains emanate, and formed by reactions involving sites or groups on existing macromolecules or by interactions between existing macromolecules.


Degree of Polymerization – The number of monomeric units in a macromolecule, an oligomer molecule, a block, or a chain.


Graft Copolymer – A copolymer that is a graft polymer.
In a graft copolymer, adjacent blocks are constitutionally different, i.e., each of these blocks comprises constitutional units derived from different characteristic species of monomer or with different composition or sequence distribution of constitutional units.

Graft Polymer – A substance composed of graft macromolecules.


Homopolymer – A polymer derived from one species of (real, implicit, or hypothetical) monomer.


Ionic Polymerization – A chain polymerization in which the kinetic-chain carriers are ions or ion-pairs.
In most cases, the growing chain ends are ions.

Irregular Macromolecule – A macromolecule in which the constitutional units are not all identical.

Irregular Polymer – A substance composed of irregular macromolecules.


Ladder Chain – A double-strand chain consisting of an uninterrupted sequence of rings, with adjacent rings having two or more atoms in common.

Linear Chain – A chain with no branch points intermediate between the boundary units (i.e. the end-groups or other branch points).

Linear Copolymer – A copolymer composed of linear macromolecules.

Long Chain – A chain of high relative molecular mass.


Macromolecule – A molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass.

Macromonomer – A macromolecule that has one end-group which enables it to act as a monomer molecule, contributing only a single monomeric unit to a chain of the final macromolecule.

Monomer – A molecule which can undergo polymerization, thereby contributing constitutional units to the essential structure of a macromolecule.


Oligomer Molecule – A molecule of intermediate relative molecular mass, the structure of which essentially comprises a small plurality of units derived, actually or conceptually, from molecules of lower relative molecular mass.


Periodic Copolymer – A copolymer consisting of macromolecules comprising more than two species of monomeric units in regular sequence.

Polymer – A substance composed of macromolecules.

Polymerization – The process of converting a monomer or a mixture of monomers into a polymer.

Pseudo Copolymer – An irregular polymer, the molecules of which are derived from only one species of monomer but which display a variety of structural features more appropriate for description in copolymer terms.

For instance, the term statistical pseudo-copolymer, could be used to describe an irregular polymer in the molecules of which the sequential distribution of configurational units obeys known statistical laws.


Radical Copolymerization – A copolymerization reaction which is a radical polymerization.

Random Copolymer – A copolymer consisting of macromolecules in which the probability of finding a given monomeric unit at any given site in the chain is independent of the nature of the adjacent units.
In a random copolymer, the sequence distribution of monomeric units follows Bernoullian statistics.

Regular Polymer – A substance composed of regular macromolecules, regular star macromolecules, or regular comb macromolecules.


Short Chain – A chain of low relative molecular mass.

Single Strand Chain – A chain that comprises constitutional units connected in such a way that adjacent constitutional units are joined to each other through two atoms, one on each constitutional unit.

Star Macromolecule- A macromolecule containing a single branch point from which linear chains (arms) emanate.

Star Polymer – A polymer composed of Star Macromolecules.


Tacticity – The orderliness of the succession of configurational repeating units in the main chain of a regular macromolecule, a regular oligomer molecule, a regular block or a regular chain.

Telomer – A substance composed of macromolecules or oligomer molecules having few, usually terminal, reactive functional groups enabling, under appropriate conditions, the formation of larger macromolecules.

Hope that was a comprehensive roundup of the different terminologies used in the context of Polymer Chemistry. Have more queries? Sumitomo Chemical Asia is happy to assist you. Reach out to us here.

*Data Source:
GLOSSARY OF BASIC TERMS IN POLYMER SCIENCE (IUPAC Recommendations 1996) – Prepared for publication by a Working Group consisting of A. D. JENKINS (UK), P. KRATOCHVIL (CZECH REPUBLIC), R. F. T. STEPTO (UK), AND U. W. SUTER (SWITZERLAND)