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W . V. Metanomski Chemical Abstracts Service, Columbus, Ohio, USA

A. Introduction B. IUPAC Recommendations 1. Source-Based Nomenclature 1.1. Homopolymers 1.2. Copolymers 1.3. Nonlinear Macromolecules & Macromolecular Assemblies 2. Structure-Based Nomenclature 2.1. Regular Single-Strand Organic Polymers 2.2. Regular Double-Strand Organic Polymers 2.3. Regular Single-Strand Inorganic and Coordination Polymers 2.4. Regular Quasi-Single-Strand Coordination Polymers 2.5. Irregular Single-Strand Organic Polymers C. Use of Common and Semisystematic Names D. Chemical Abstracts (CA) Index Names E. Polymer Class Names F. References A.

1-1 1-1 I-2 I-2 I-2 I-3 I-3 I-6 I-6 I-7 I-7 I-8 I-8 1-11 1-12

INTRODUCTION

Macromolecular (polymer) nomenclature has an almost 50-year history. As early as 1949 there existed a Subcommission on Nomenclature within the International Union of Pure and Applied Chemistry (IUPAC) under the chairmanship of Maurice L. Huggins. The Subcommission was part of the IUPAC Commission on Macromolecules, chaired then by Herman F. Mark. Other notable pioneers in polymer science, Jan Joseph Hermans, Otto Kratky, Harry W. Melville, and George J. Smets, were members of the Commission. The Subcommission produced its first official report in 1952. It recognized then, what is just as true today, that the practice in the field of small molecules of providing rigorous definitions is impractical for polymers. The latter consist of molecules not necessarily exactly of the same size, chemical composition, or structure. The differences result from the presence of end groups, branches, variation in orientation of monomeric units, and irregularity in the sequence of different types of units. The American Chemical Society (ACS) Division of Polymer Chemistry established its Nomenclature Commit-

tee in 1963 to try to unify earlier attempts to name polymers in some coherent way. Their first major project resulted in a structure-based nomenclature for regular linear polymers, first published in ACS Polymer Preprints in 1967, adopted by Chemical Abstracts in 1968, and incorporated in IUPAC recommendations in 1975 [I]. When the IUPAC Commission on Macromolecules was elevated to become the IUPAC Division of Macromolecular Chemistry, the latter in turn established its Commission on Macromolecular Nomenclature in 1968. The Commission in the course of its nearly 30 years of existence produced a series of major documents that have shaped modern nomenclature and terminology of polymer science. The recommendations are being published in the IUPAC official journal, Pure and Applied Chemistry, and occasionally are republished in the form of a "Compendium" which groups all the currently valid documents in a single volume. The Commission published its "Compendium of Macromolecular Nomenclature" in 1991 [2]. The book, which IUPAC has designated the "Purple Book", in analogy to other IUPAC books ("Blue" - organic, "Red" - inorganic, "Orange" - analytical, "Green"- physical, and "Gold" - overall chemistry), has the two most basic macromolecular nomenclature recommendations: "nomenclature of regular single-strand organic polymers" and "source-based nomenclature for copolymers". In more recent years, the Commission extended that basic nomenclature to double-strand (ladder and spiro) organic polymers, irregular and crosslinked polymers, and polymer blends and interpenetrating networks. In this article, the basic structure-based and source-based nomenclature of polymers is explained and illustrated in some detail. The continuing use of common and semisystematic nomenclature with reference to specific tables in this Handbook is highlighted. The current Chemical Abstracts (CA) index names [3] are compared and contrasted with the IUPAC practice and typical names employed in the polymer journals and textbooks. B.

IUPAC RECOMMENDATIONS

Since polymers, unlike low-molecular-weight compounds, have no uniform structure and are mixtures of macromolecules of different length and different structural

arrangement, their graphical representation and their names require a special approach. Often enough, the structure of the polymer has not been sufficiently characterized and the researcher cannot draw its chemical structure. Consequently, no name of the polymer reflecting its structure is possible. A polymerization reaction for a polymer formed from a monomer such as vinyl chloride can schematically be represented by

polybutadiene polyethylene poly(methyl methacrylate) poly(methyl vinyl ether) polystyrene poly(tetrafluoroethylene) poly(vinyl alcohol) poly(vinyl acetate) poly(vinyl chloride) poly(vinylidene dichloride)

That shows an idealized product. In fact, however, the polymer consists of long-chains of various lengths. The repeating units, - C H 2 - C H C l - , are not necessarily all uniquely oriented and joined in a regular fashion as shown in the idealized structure above. In addition to "head-totail" links

Parentheses are used when the name of the monomer consists of two or more words, and when the monomer has substituents. These are all olefinic type reactants, from which two carbon atoms originally linked by a double bond form a bivalent group:

other links such as "head-to-head"

where R and R [ represent a hydrogen atom or a substituent group. Many of these are joined, in turn, to each other but their exact orientation or sequence is seldom known. On the other hand, different polymers derived from a single monomer and having identical constitutional units can still be differentiated by additional information, such as average molecular weight and other chemical and physical characteristics.

and "tail-to-tail"

can occur, and the exact sequence of all these repeating units usually is not known. This becomes even more complicated when a copolymer is derived from more than one monomer, such as styrene and methyl acrylate, which contribute two constitutional or monomeric units:

They can combine into a polymeric chain, resulting in many types such as unspecified, statistical, random, alternating, periodic, block, or graft copolymers. Because the exact structure of the polymer is not always known, two systems of naming polymers exist: source-based nomenclature, structure-based nomenclature. 1.

Source-Based Nomenclature

1.1. Homopolymers Homopolymers are derived from only one species of monomer, which may be the actual starting reactant (or source), or be a hypothetical monomer if the homopolymer is formed by a modification of another homopolymer. The name of the polymer is formed by attaching the prefix "poly" to the name of the actual or assumed monomer, or the starting reactant (source), from which the polymer is derived. Examples: poly (acrylic acid) polyacrylonitrile

1.2. Copolymers For copolymers, the names of monomers are cited after the prefix "poly". In addition, an italicized connective (infix) is placed between the names of monomers to denote the kind of sequential arrangement by which the constitutional (monomeric) units, derived from each monomer, are related in the structure [4]. Seven types of sequence arrangements are listed with their corresponding connectives:

Type

Connective

unknown or unspecified statistical (obeying known statistical laws) random (obeying Bernoullian distribution) alternating (for two monomeric units) periodic (ordered sequence of more than two) block (linear arrangement of blocks) graft (side blocks chains connected to main chain)

Examples:

-co-stat-raft-alt-per-block-graft-

poly[styrene-C(?-(methyl methacrylate)! poly^tyrene-statf-acrylonitrile-statf-butadiene) poly[ethylene-ran-(vinyl acetate)] poly[(ethylene glycol)-tf/r-(terephthalic acid)] poly[formaldehyde-/?er-(ethylene oxide)-per(ethylene oxide)] polystyrene-&/oc&-polybutadiene polybutadiene-gra/f-polystyrene

The names of the monomers are those common or semisystematic names that are encountered most often in the literature of polymer science. The order of citation of monomers in copolymer names is arbitrary. An equally acceptable alternative scheme for naming copolymers utilizes the prefix "copoly", followed by citation of the names of the monomers, separated by an oblique stroke (a solidus). Parentheses are not needed to enclose monomer names consisting of two or more words. Examples:

the constituent macromolecules with an italicized connective between them. Examples:

copoly(styrene/methyl methacrylate) j"tatf-copoly(styrene/acrylonitrile/butadiene) ran-copoly(ethylene/vinyl acetate) a/f-copoly(ethylene glycol/terephthalic acid) per-copoly(formaldehyde/ethyleneoxide/ethylene oxide) Wtfc/:-copoly(styrene-butadiene) gra/£-copoly(butadiene-styrene)

1.3. Nonlinear Macromolecules and Macromolecular Assemblies Most recently, the source-based nomenclature has been extended for non-linear macromolecules and macromolecular assemblies [5], The non-linear macromolecules comprise branched, graft, comb, star, cyclic, and network macromolecules. The macromolecular assemblies comprise polymer blends, interpenetrating polymer networks, and polymer-polymer complexes. The following italicized qualifiers can be used as both prefixes (e.g., blend-, net-) and infixes (connectives) (e.g., -blend-, -net-) to designate the skeletal structure of nonlinear macromolecules or macromolecular assemblies:

Type cyclic branched, unspecified short-chain-branched long-chain-branched branched with branch point of functionality / comb star star with / arms network crosslink polymer blend interpenetrating polymer network semi-interpenetrating polymer network polymer-polymer complex

Connective cyclo branch sh-branch l-branch f-branch comb star f-star net t (Greek iota) blend ipn sipn compl

2.

poly styrene-com£>-poly aery lonitrile com&-poly(styrene~statf-acrylonitrile) poly styrene-comZ?- [poly acrylonitrile; poly(methyl methacrylate)] 4-sfar-polystyrene star-(po\yA-block-polyB-block-polyC) star-(polyA; polyB; polyC) star-(polyacrylonitrile; polystyrene) (M1 100000:20000) fte£-polystyrene-£-divinylbenzene n^-poly[styrene-