2Chemical Abstracts Service, Columbus, Ohio 43210

Most chemists are familiar with the IUPAC nomenclature of organic chemistry, detailing how to name various organic compounds. Similar nomenclature exists for polymers.^1,2 This is the second paper³ in Polymeric Materials Science and Engineering preprints devoted to polymer nomenclature, with an emphasis on polymer materials.

This paper will emphasize the very many multicomponent polymer structures which are known to exist. While some are well-known, others are rare, novel, or would be considered by some to be "odd-ball."

The polymer structures to be considered are illustrated in Figure 1. Structures (a) through (e) are, respectively, the polymer blends, grafts, blocks, interpenetrating polymer networks, and AB-crosslinked copolymers. These are the relatively well-known materials. The nomenclature rules for (a), (b), and (c) were published.¹ Nomenclature rules for (d), (e), (h), and (i) are now under consideration by the IUPAC Commission on Macromolecular Nomenclature. Simple materials, using, for example, polybutadiene as polymer I and polystyrene as polymer II, might be named:

polybutadiene-blend-polystyrene (a)

polybutadiene-block-polystyrene (b)

polybutadiene-graft-polystyrene (c)

(net-polybutadiene )-ipn-(net-polystyrene) (d)

One of the authors has frequently written (d) as:

cross-polybutadiene-inter-cross-polystyrene (d)'

polybutadiene-net-polystyrene (e)

star-(polybutadiene-block-polystyrene) (h)

Note that the polybutadiene is the inside block.

star-(polybutadiene; polystyrene) (i)

Structure (i) is called a segregated star copolymer to differentiate it from the starblock copolymer, structure (h). In so far as the authors are aware, no systematic IUPAC nomenclature has yet been proposed for the remaining macromolecular structures. Structures (f) and (g) have been broadly described,⁴ and are known as catenanes and rotaxanes, respectively. The rotaxanes were the subject of a recent symposium.⁵ The connective -rotaxa- has been proposed to describe the relationship of the polymer chain to the small rings which are threaded on.⁶ Perhaps the connective -catena- might be used for the polymeric catenanes, although a detailed nomenclature would have to be worked out to express the number of rings attached, and whether the rings were of the same or different polymers.

The structure (j) was described by Kim and Choi⁷ as an inclusion complex, where amylose in such solvents as DMSO is stiff and predominantly helical. Various dye molecules could be permantly trapped in the helix as guest molecules. Perhaps the connective -inclus- might be considered to describe the relationship between the chains.

The structure (k) forms the cascade polymers,^8,9 which are named in some detail by Newkome, et al.⁸ The general nomenclature adapted used the notation:

Z-cascade:core unit[N_c]:(intermediate repeat unit)ⁿ:terminal unit (1)

where Z represents the number of terminal units, the core unit is the initial mer, N_c is the multiplicity of branching from the central core, and n is the number of layers of repeated units, i.e., the number of generations of intermediate repeat mers joined in cascade fashion, and the terminal unit is the terminal mer.

As a simple example, we have:

36-Cascade:methane [4]:( 3-oxo-6-oxa-2-azaheptylidyne)²:4-oxapentanoic acid (2)

which represents a second-generation cascade polymer.

In conclusion, while the nomenclature of polymer materials has advanced to the point where all of the common materials are either fully described by IUPAC or under consideration, there are many new ones yet to be considered in any systematic way. The authors would be pleased to receive any comments or suggestions regarding polymer nomenclature.