1: Glossary of Basic Terms in Polymer Science

CONTENTS

Preamble

1. Molecules and molecular structure

2. Substances

3. Reactions

Alphabetical index of terms

PREAMBLE

In order to present clear concepts it is necessary that idealized definitions be adopted but it is recognized that the realities of polymer science must be faced. Deviations from ideality arise with polymers at both molecular and bulk levels in ways that have no parallel with the ordinary small molecules of organic or inorganic chemistry. Although such deviations are not explicitly taken into account in the definitions below, the terms recommended can usefully be applied to the predominant structural features of real polymer molecules, if necessary with self-explanatory, if imprecise, qualifications such as 'essentially....', 'almost completely....', or 'highly....'. Although such expressions lack the rigour beloved by the purist, every experienced polymer scientist knows that communication in this discipline is impossible without them.

Conventionally, the word polymer used as a noun is ambiguous; it is commonly employed to refer to both polymer substances and polymer molecules. Henceforth, macromolecule is used for individual molecules and polymer is used to denote a substance composed of macromolecules. Polymer may also be employed unambiguously as an adjective, according to accepted usage, e.g., polymer blend, polymer molecule.

1 MOLECULES AND MOLECULAR STRUCTURE

1.1 macromolecule

polymer molecule

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.

Note 1: In many cases, especially for synthetic polymers, a molecule can be regarded as having a high relative molecular mass if the addition or removal of one or a few of the units has a negligible effect on the molecular properties. This statement fails in the case of certain properties of macromolecules which may be critically dependent on fine details of the molecular structure, e.g., the enzymatic properties of polypeptides.

Note 2: If a part or the whole of the molecule has a high relative molecular mass and essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass, it may be described as either macromolecular or polymeric, or by polymer used adjectivally.

Note 3: In most cases, the polymer can actually be made by direct polymerization of its parent monomer but in other cases, e.g., poly(vinyl alcohol), the description 'conceptual' denotes that an indirect route is used because the nominal monomer does not exist.

1.2 oligomer molecule

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.

Note 1: A molecule is regarded as having an intermediate relative molecular mass if it has properties which do vary significantly with the removal of one or a few of the units.

Note 2: If a part or the whole of the molecule has an intermediate relative molecular mass and essentially comprises a small plurality of units derived, actually or conceptually, from molecules of lower relative molecular mass, it may be described as oligomeric, or by oligomer used adjectivally.

1.3 monomer molecule

Molecule which can undergo polymerization, thereby contributing constitutional units to the essential structure of a macromolecule.

1.4 regular macromolecule

Macromolecule, the structure of which essentially comprises the repetition of a single constitutional unit with all units connected identically with respect to directional sense.

1.5 irregular macromolecule

Macromolecule, the structure of which essentially comprises the repetition of more than one type of constitutional unit, or a macromolecule the structure of which comprises constitutional units not all connected identically with respect to directional sense.

1.6 linear macromolecule

Macromolecule, the structure of which essentially comprises the multiple repetition in linear sequence of units derived, actually or conceptually, from molecules of low relative molecular mass.

1.7 regular oligomer molecule

Oligomer molecule, the structure of which essentially comprises the repetition of a single constitutional unit with all units connected identically with respect to directional sense.

1.8 monomeric unit

monomer unit

mer

Largest constitutional unit contributed by a single monomer molecule to the structure of a macromolecule or oligomer molecule.

Note: The largest constitutional unit contributed by a single monomer molecule to the structure of a macromolecule or oligomer molecule may be described as either monomeric, or by monomer used adjectivally.

1.9 macromonomer molecule

Macromolecule or oligomer molecule 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.

1.10 macroradical

Macromolecule which is also a radical.

1.11 prepolymer molecule

Macromolecule or oligomer molecule capable of entering, through reactive groups, into further polymerization, thereby contributing more than one constitutional unit to at least one type of chain of the final macromolecules.

Note: A prepolymer molecule capable of entering into further polymerization through reactive end-groups, often deliberately introduced, is known as a telechelic molecule.

1.12 macromonomeric unit

macromonomer unit

Largest constitutional unit contributed by a single macromonomer molecule to the structure of a macromolecule.

1.13 degree of polymerization

Number of monomeric units in a macromolecule an oligomer molecule, a block, or a chain.

1.14 constitutional unit

Atom or group of atoms (with pendant atoms or groups, if any) comprising a part of the essential structure of a macromolecule, an oligomer molecule, a block, or a chain.

1.15 constitutional repeating unit (CRU)

Smallest constitutional unit, the repetition of which constitutes a regular macromolecule, a regular oligomer molecule, a regular block, or a regular chain.

1.16 configurational unit

Constitutional unit having at least one site of defined stereoisomerism.

1.17 configurational base unit

Constitutional repeating unit in a regular macromolecule, a regular oligomer molecule, a regular block, or a regular chain, the configuration of which is defined at least at one site of stereoisomerism in the main chain.

1.18 configurational repeating unit

Smallest set of successive configurational base units that prescribes configurational repetition at one or more sites of stereoisomerism in the main chain of a regular macromolecule, a regular oligomer molecule, a regular block, or a regular chain.

1.19 stereorepeating unit

Configurational repeating unit having defined configurations at all sites of stereoisomerism in the main chain of a regular macromolecule, a regular oligomer molecule, a regular block, or a regular chain.

1.20 tacticity

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.

1.21 tactic macromolecule

Regular macromolecule in which essentially all the configurational (repeating) units are identical.

1.22 stereoregular macromolecule

Regular macromolecule essentially comprising only one species of stereorepeating unit.

1.23 isotactic macromolecule

Tactic macromolecule, essentially comprising only one species of configurational base unit, which has chiral or prochiral atoms in the main chain in a unique arrangement with respect to its adjacent constitutional units.

Note: In an isotactic macromolecule, the configurational repeating unit is identical with the configurational base unit.

1.24 syndiotactic macromolecule

Tactic macromolecule, essentially comprising alternating enantiomeric configurational base units, which have chiral or prochiral atoms in the main chain in a unique arrangement with respect to their adjacent constitutional units.

Note: In a syndiotactic macromolecule, the configurational repeating unit consists of two configurational base units that are enantiomeric.

1.25 atactic macromolecule

Regular macromolecule that has an equal number of the possible configurational base units in a random sequence distribution.

1.26 block macromolecule

Macromolecule which is composed of blocks in linear sequence.

1.27 junction unit

Non-repeating atom or non-repeating group of atoms between blocks in a block macromolecule.

1.28 graft macromolecule

Macromolecule with one or more species of block connected to the main chain as side-chains, these side-chains having constitutional or configurational features that differ from those in the main chain.

1.29 stereoblock macromolecule

Block macromolecule composed of stereoregular, and possibly some non-stereoregular, blocks.

1.30 chain

Whole or part of a macromolecule, an oligomer molecule, or a block, comprising a linear or branched sequence of constitutional units between two boundary constitutional units, each of which may be either an end-group, a branch point, or an otherwise-designated characteristic feature of the macromolecule.

Note 1: Except in linear single-strand macromolecules, the definition of a chain may be somewhat arbitrary.

Note 2: A cyclic macromolecule has no end-groups but may nevertheless be regarded as a chain.

Note 3: Any number of branch points may be present between the boundary units.

Note 4: Where appropriate, definitions relating to macromolecule may also be applied to chain.

1.31 subchain

Arbitrarily chosen contiguous sequence of constitutional units, in a chain.

Note: The term subchain may be used to define designated subsets of the constitutional units in a chain.

1.32 linear chain

Chain with no branch points between the boundary units.

1.33 branched chain

Chain with at least one branch point between the boundary units.

1.34 main chain

backbone

That linear chain to which all other chains, long or short or both, may be regarded as being pendant.

Note: Where two or more chains could equally be considered to be the main chain, that one is selected which leads to the simplest representation of the molecule.

1.35 end-group

Constitutional unit that is an extremity of a macromolecule or oligomer molecule.

Note: An end-group is attached to only one constitutional unit of a macromolecule or oligomer molecule.

1.36 long chain

Chain of high relative molecular mass.

Note: See Note 1 to Definition 1.1.

1.37 short chain

Chain of low relative molecular mass.

Note: See Note 1 to Definition 1.2.

1.38 single-strand chain

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.

1.39 single-strand macromolecule

Macromolecule 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.

1.40 double-strand chain

Chain consisting of an uninterrupted sequence of rings with adjacent rings having one atom in common (spiro chain) or two or more atoms in common (ladder chain).

1.41 double-strand macromolecule

Macromolecule consisting of an uninterrupted sequence of rings with adjacent rings having one atom in common (spiro macromolecule) or two or more atoms in common (ladder macromolecule).

1.42 spiro chain

Double-strand chain consisting of an uninterrupted sequence of rings, with adjacent rings having only one atom in common.

Note: A spiro chain is a double-strand chain with adjacent constitutional units joined to each other through three atoms, two on one side and one on the other side of each constitutional unit.

1.43 spiro macromolecule

Double-strand macromolecule consisting of an uninterrupted sequence of rings, with adjacent rings having only one atom in common.

Note: A spiro macromolecule is a double-strand macromolecule with adjacent constitutional units joined to each other through three atoms, two on one side and one on the other side of each constitutional unit.

1.44 ladder chain

Double-strand chain consisting of an uninterrupted sequence of rings, with adjacent rings having two or more atoms in common.

Note: A ladder chain is a double-strand chain with adjacent constitutional units joined to each other through four atoms, two on one side and two on the other side of each constitutional unit.

1.45 ladder macromolecule

Double-strand macromolecule consisting of an uninterrupted sequence of rings, with adjacent rings having two or more atoms in common.