To provide systematic and practical recommendations for source-based nomenclature of single-strand organic polymers.
NECESSITY OF A NEW DOCUMENT
When the structure-based nomenclature of polymers was first published (1976), the commission of macromolecular nomenclature expected that the system would be soon widely used. But this was not the case and the source-based names, of which only ca.20 were allowed as exceptions in the Appendix of the document, still prevail over structure-based.
Though the structure-based nomenclature is very systematic and logical so as to give only one name for one polymer, it often results in very complex or very long names contrary to the economics of expression (short, easy to understand, easy to memorize, etc). This is one of the reasons why structure-based names are not so popular. Another reason for the preference for source-based names is their direct relation to monomer names and to the historical trivial names. Even the commission itself decided to use source-based names in the Copolymer document (1985) because of their simplicity and practicality. But no clear definitions or rules for the basic concepts of source-based nomenclature were given there. Very recently the commission officially admitted for the first time the general use of the source-based nomenclature for homopolymers in the “Generic” document (2001) saying that “The commission has now decided to recommend source-based nomenclature as an alternative official nomenclature for homopolymers”.
However, because the source-based nomenclature has been treated as a second ranked nomenclature for a long time, no scrutiny has been made on it and many problems have been left unsolved, e.g., there are many cases in which one polymer has two or more names without any seniority rules or one name corresponds to several different polymers. It is desirable to minimize such shortcomings while keeping the practicality of the source-based nomenclature.
ISSUES TO BE RECONSIDERED
Among many issues to be reconsidered, some examples are briefly shown in the following.
1) Issues relevant to both homopolymers and copolymers
1-1 Establish the rules for choosing the name(s) of a monomer from two or three different names, i.e., (1) IUPAC systematic name (e.g., ethene, vinylbenzene, oxirane, etc.), (2) IUPAC approved trivial names (e.g., styrene) and (3) trivial names not approved by IUPAC (e.g., ethylene, ethylene oxide,).
1-2 Select one preferred name among plural names all conforming to the rules to have only one preferred name for one polymer as far as possible.
1-3 Expand the definition of the source-based name to be able to cover PET (polyethylene terephthalate) type names (See 3-2).
2) Issues relevant only to homopolymers
Find better generic names for the isomeric regular homopolymers and irregular homopolymers such as polyisoprenes, for which the generic convention allows to distinguish isomeric plural homopolymers, e.g., polyalkylene:isoprene and polyalkenylene;isoprene. Use of simpler class names, such as poly(1,2-adduct):isoprene, poly (cis-1,4-adduct):isoprene, have to be discussed.
3) Issues relevant only to copolymers
3-1 Discard the “alternative nomenclature”given in the Appendix of the current Copolymer document, to avoid having two nomenclature systems.
3-2 Avoid many names for a copolymer prepared by polycondensation, in which a same regular copolymer can be prepared from different monomers ,e.g. monomer A) ethylene glycol, ethylene oxide, etc. and monomer B) terephthalic acid or various acid derivatives.
STRUCTURE OF THE NEW DOCUMENT
Due to the tight correlations among nomenclature of homopolymers, that of copolymers, and the generic nomenclature, it is desirable to have all of them in one document. Most part of the current “Copolymer document” (1985) and the “Generic document” (2001) will be incorporated in the new document probably by modifying them in more concise form, eventually superseding them. The document “Source-based nomenclature of nonlinear macromolecules and macromolecular assemblies” is of different nature and should not be included in this document.
1. Introduction (Reasons for revision / Scope)
2. General (Definitions / Generic Convention / Preferred names)
3. Names of Monomers (Allowed trivial/Systematic/ Hypothetical)
4. Homopolymers (Basic rules/ Use of generic names)
5. Copolymers (co, stat, ran, alt, per / block,graft/ PET type names/ Use of generic convention for complicated copolymers)
August 2014 – After several rounds of revisions during the last months, a draft of “Source-Based Nomenclature for Single-Strand Homopolymers and Copolymers” is being finalized and will be soon shared for public review.
July 2015 – the provisional recommendations titled ‘Source-Based Nomenclature for Single-Strand Homopolymers and Copolymers’ is made available for public review until 31 December 2015.
Nov 2016 update – The IUPAC Recommendations 2016 has been published in PAC online 26 Nov 2016, Volume 88, Issue 10-11, Pages 1073-1100, DOI: 10.1515/pac-2015-0702
Page last update 28 Nov 2016