Page 28 - Carrahers_Polymer_Chemistry,_Eighth_Edition

Polymer Nomenclature xxvii

CA organizes the naming of materials into twelve major arrangements that tie together about 200
subtopics. These main topic headings are as follows:

A. Nomenclature systems and general principles
B. Molecular skeletons
C. Principle chemical groups
D. Compound classes
E. Stereochemistry and stereoparents
F. Specialized substances
G. Chemical substance names for retrospective searches
H. Illustrative list of substitute prefi xes
J. Selective bibliography of nomenclature of chemical substances
K. Chemical prefi xes
L. Chemical structural diagrams from CA Index Names
M. Index

The section dealing with polymers is subtopic 222. Polymers. The subsection dealing with polymers
builds on the foundations given before and thus some of the guidelines appear to be confusing and
counterproductive to the naming of polymers but the rules were developed for the naming of small
molecules. Following is a description of the guidelines that are most important to polymer chemists.
Additional descriptions are found in the CA Appendix IV itself and in articles given in the readings.
The Appendix IV concentrates on linear polymers. A discussion of other more complex polymeric
materials is also found in articles cited in the readings section.

GENERAL RULES
In searching the chemical literature, in particular systems based on CA, searches for particular
polymers can be conducted using the Chemical Abstract Service Number, CAS # (where known),
or by repeat unit. The IUPAC and CAS have agreed upon a set of guidelines for the identifi cation,
orientation, and naming of polymers based on the structural repeat unit (SRU). IUPAC names poly-
mers as “poly(constitutional repeat unit)” while CAS utilizes a “poly(structural repeating unit).”
These two approaches typically give similar results.

Here we will practice using the sequence “identification, orientation, and naming” first by giving
some general principles and finally by using specifi c examples.

In the identifi cation step, the structure is drawn, usually employing at least two repeat units.
Next, in the orientation step, the guidelines are applied. Here we will concentrate on basic guide-
lines. Within these guidelines are subsets of guidelines that are beyond our scope.
Structures will be generally drawn in the order, from left to right, in which they are to be named.

SENIORITY
The starting point for the naming of a polymer unit involves determining seniority among the subunits.
A. This order is
Heterocyclic rings>
Greatest number of most preferred acyclic heteroatoms>
Carbocyclic rings>
Greatest number of multiple bonds>
Lowest or closest route (or lowest locant) to these substituents>
Chains containing only carbon atoms
with the symbol “>“ indicating “is senior to.”

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