Polymer Nomenclature-or What's in a Name? Charles E. Carraher, Jr. Florida Atlantic University, Boca Raton, FL 33431 George Hess Wright State University, Dayton, OH 45435 L. H. Sperling Polymer Science and Engineering Program. Department of Chemical Engineering, Materials Research Center #32,Lehigh University, Bethlehem. PA 18015 While the science of polymers developed relatively recently, the art of polymers is ancient. Names associated with selected polymers were often historically derived with few overall guiding principles. Further, the differing hackgrounds of polymer scientists and the wide variety of polymeric materials (organic, inorganic, and natural) encouraged this diversity in names. In fact, the very name "polymer" is derived from the Greek words poly meaning "many" and meros meaning "parts". This article will concentrate on the naming of linear organic polymers, the most common polymers used by our society. Four major types of names for polymers will he discussed: common names, source-based names, characteristic grouo. names. and structure-based names. Finallv. .. the specification of tacticity and geometric isomerism, which are a s ~ e c t of s the three-dimensional arrangements of the ~ o l v mers, will he introduced. Common Names Little "rhyme or reason" is associated with the common names for polymers. Some names are derived from the place of origin of the material, such as Hevea hrasiliensis, literally "rubber from Brazil", for natural rubber. Other polymers are named after their discoverer, as is Bakelite, the threedimensional polymer produced by condensation of phenol and formaldehyde, which was developed by Leo Baekeland in 1905. While other polymers had been synthesized earlier, Bakelite was the first commercial synthetic polymer. It is actually a subgroup of a larger class of polymers produced from formaldehyde, which have been given the generic name, acetal resins. For some important groups of polymers, special names and systems of nomenclature were invented. The nylons were one such group. These polymers were named according to the number of carbons in the diamine and carhoxylic acid reactants (monomers) used in their syntheses. The nylon produced by the condensation of I&hexanediamine (six carbons) and sebacic acid (10 carbons) is called nylon-6,lO. 0 nH2N(CHr)sNHr 1.6-hexanediamine
I/
/I
polystyrene
The vast majority of polymers based on the vinyl group (CH2=CHX) or the vinylidene gronp (CH2=CXg) as the repeat unit are known by their source-based names. For example, polyethylene is derived from the monomer ethylene, poly(viny1 chloride) from the monomer vinyl chloride, and poly(methy1 methacrylate) from methyl methacrylate: COOCH:,
i
nCH2='i
-
COOCH,, I
CCH?--CH+,
I
CH,
CH:, methyl methacrylate
pdy(rnethyl methacrylate)
A sampling of source-based polymer names is given in Table 1, along with standard abbreviations and some trade or brand names. Many condensation polymers are also named in this manner. In the case of poly(ethy1ene terephthalate), the glycol portion of the name of the monomer, ethylene glycol, is elided in constructing the polymer name, so that the name is actually a hybrid of a source-based and a structure-based name. 0 1inHOCH2CH?OH
+
nHOC
COH
-
tereohthalic
--r
sehacic acid
n -
II
n -
II
t N H ( C H & N H C i C H 2 ) ~ C + t 2nHzO nylon-fiJ0
Similarly the polymer from 1,6-hexanediamine and adipic acid (both having six carbons) is called nylon-6,6 or nylon66; and the nylon from the single reactant caprolactam (six carbons) is called nylon-6. Source-Based Names The majority of polymer names familiar to polymer scientists are source-based. That is, they are based on the name36
styrene
ethyl glycol
0
+ nHOCiCHJaCOH
often the common name-of the reactant monomer, preceded by the prefix "poly". For example, polystyrene is the most frequently used name for the polymer derived from the monomer 1-phenylethene, which has the common name styrene.
Journal of Chemical Education
polyiethylene terephthalate)
This polymer is well known by trade names such as Dacron. Copolymers are those polymers composed of two or more monomer units. Source-based names are conveniently used to describe copolymers by using an appropriate term hetween the names of the monomers. Any of a half dozen or so connecting terms may be used depending on what is known about the structure of the copolymer. When no information is specified about the sequence of monomer units in the
Table 1. Llstlng of Source-NamedVinyl Polymers Source Monomer Styrene
Source-Based Polymer Name
Abbreviation
Examples of Trade or Brand Names
Polystyrene
Carinex, Celatron, Cellofoam, Dylene. Evengio, Fostarene, Kardei, Lustrex, Pelaspan. Slyrocel. Styrofoam, Slyron
Polyethylene
Alathon, Courlene. Cronar. Duremene. Dylan. El Rey, Ethron. Fortiflex. Grex. Hi-fax. Hipack. Microthene. Pearlon. Petrothene. Poly-eth. Zendel
Acrylonitriie
PAN
Acrilan. Courtelle
Tetrafluaroemylene
PTFE
Algoflon. Fluon. Fluoroplart, Soreflan. Teflon. Tetra"
Isoprene
Poiyisoprene
IR, NRB
Amerlpol, Coral Rubber
Vinyl chloride
Paly(vinyl chloride)
PVC
Ampcaflex, Benric, Carina. Cobex. Corda. Dacovin. Daren, Gem, Karaseal, Matvinal. Opalon. PeeVeeCee, Plioflex. Pliovic, RUCOI. Uitryl
Polychloroprene
Baypren. Neoprene
Polypropylene
Bexphane. Cryavac, Dynafilm. Lupsren, Molplen. Olefane. Polylumy, Propathene Budene. Cis-4
Methyl methacrylate Vinylidene dichloride
Poly(methy1methacrylate) Poly(viny1idene dichloride)
PMMA PVDC
Degalan. Plexiglas Saran. Viclan
Natural rubber.
copolymer, the connective term "-co-" is used in the general format poly(A-co-B), where A and B are the names of the two monomers. An unspecified copolymer of styrene and methyl methacrylate would be called poly[styrene-co(methyl methacrylate)]. Kraton. the vellow rubber on the bottom of many running shoes is an example of n copolynler about which structural informatwn isavailable. I t is formed from a groupof styrene units, i.e., a "block" of polystyrene, attached t o a group of butadiene units, or a block of polybutadiene, which is attached to another block of polystyrene, forming a triblock copolymer. The general representation of such a block copolvmer is -AAAAABBBBBAAAAA-.where each A or B remeients an individual monomer u n i t : ~ h eproper source-based name for Kraton is oolvstvrene-block-polvbutadiene-blockpolystyrene, with the prefix "poly-" being retained for each block. Connective terms other than -co- and -block- are presented, and their uses described, in reference 1. Characteristic Group Names Condensation polymers are often referred to by a family name that is based on the name of the connecting linkage in the polymer-normally a simple organic functional group. In this system nylon is referred to as a polyamide and poly(ethylene terephthalate) is called a polyester.
nvkm-6.10
pdy(ethylene terephthalate)
amide
ester
pn,up
px'up
a pdyamide
a pdyester
It is immediately obvious that one can only refer to classes of polymers using the group name approach, since each functional group such as amide or ester may have any number of different organic groups attached. A few of the classes of polymers named by the characteristic connecting functional groups are listed in Table 2, along with their structures and representative trade or brand names. Structure-Based Names While source-based names are aenerallv employed for . . simple pulymw.;, the interilationnl Iludy r~sponsihletor systenintic numrnclature of chrmicilk. I11I'.\C', hns puhlished a number of papers for the naming of polymers, which are now being accepted for more complex polymers (1-5). The IU~ ~ C ~ s y s names t e m the components of the repeat unit, arVolume 64 Number 1 January 1987
37
Table 2.
0
H
I II
R'-N-C-R
O
O
II
CN-C-R-C-N-R+
Ester
+C-O-R-O-C-R'+
0
I1
Polyamide
Akulan, Aramide. Antron. Candon. Capran. Owethan, Enkalure. Herox. H-film. Hylar. Maranyl, Nomex. Tynex. Zytel
Polyester
Amite. Aropol, Atlac, Celanar. Crastin. Dacron, Oerakane, Oion. Fortrel, Kodel. Melinex, Multron, Mylar, Scotchpak. Slectron. Terylem. Varex. Vibrin. Videne. Vile1
Polycarbonate
Babylon, lupilon, Makrofol. Markralon Merlon, Nuclon
0
I/
0
Example of Trade 01 Brand Names
H
II I
Amide
0 R'-C-OR
Polymer Family Name
Polymer Repeating Unit
Organic Family Name
Group Structure H
Listing of Polymers According to Their Functional Connective Groups
Ii
0
li
ROCOR
Carbonate
0
0
Ii
R'--C-O-C-R
0
I1
R-S.-R R-O-R H
O
0
I
II
tS-R+
Polysullide
f O-R+
Polyether
Urethane
H
R'-N-C-N-R
0
Sulfide
H
I I! I
I
CC-O-C-R-C-O-C-R'+
Ether
R'-N-C-O-R
0
I
Anhydride
0
I I1
H
II
tO-C-O-Rt
Urea
0
I I/
CN-C-O-R-O-C-N-R'+
pdystyren?
b
H
i
I
H
O
H
H
O
H
I
l
i
I
i
I
CN-C-N-R-N-C-N-R'I
ranged in a prescribed order. The rules for selecting the order of the components to be used as the repeat unit are beyond the scope of this paper. However, once the order is selected, the naming is straightforward for simple linear molecules, as indicated in the following examples:
f CH--CH,hr
0
Polyanhydride
Polyurethane
Thlokol
Adiprene, Carslab. Castethane. Chemigum. Cyanaprene. Desmopan. Elastothane. Isofoam. Molotopren. Nimbus. Perlon. Roylar. Safom. Spandex. Spraythane. Texin, Thurane. Vithane
Polyurea
Three-Dimensional Structure: Tactlclty and Geometric Isomerism
The specification of two aspects of the three-dimensional structures of polymers deserves mention because of wide application. Polymers containing certain features such as rings or double bonds may exhibit geometric isomerism. Cistrans isomers are a common example of this class of compounds. Polyisoprene may exist in either the cis or the trans form, as indicated.
polyll-phenylethylenel tronr-polyisoprene
cir-pdyisoprene
p d y l m e t h y i methacrylate)
The cis-polyisoprene is natural rubber, a soft, tough elastomer; whereas trans-polyisoprene is highly crystalline, and suitable for golf ball covers. A more subtle type of isomerism is stereoregularity or tacticity. The alternating carbons in a polymer like poly(vinyl chloride) are chiral centers, and certain combinations of 38
Journal of Chemical Education
configurations about these chiral centers are given names. When all the centers have the same configuration the poly-
mer is called isotactic, "it"; when the centers have regularly alternating configurations, the polymer is said to he syndiotactic, "st" and when the centersire of random configuration, it is atactic, "at". These possibilities are depicted in the figure. Summary
Polymers have several naming systems, and which one will be encountered by the reader depends on how widely known the polymer is, as well as on the style of the author. There are several recent books on polymers that explore broad areas of polymer science for interested readers (6-10). Literature Clted I.IUPAC Macromoleeulsr Div. Comm Macromoleeuisr Nomenclature. Pure Appi.
n "u "
0. Various tactic (stereoregular) forms
of poly(1-chloroethylene). showing Only
the geometry of the chiral carbons. Top. Isatactic-all chlorines oriented in the same direction: middle, syndiotactic-chlorines regularly alternating; bottom, atacti-chlorines randomly oriented.
Them. 1385,57,1427-1440. 2. IUPAC Mncromolecular Nomenclature Cumm. Maciomolacuir 1373.6, 149-158. 8. IUPAC Macromolecular Div. Comm Macromoleeulsr Nomenclature; IUPAC Inorzanicchem. Div. Comm. Nomenelsture lnorg. Chem. Pure Appi. Chem. 1985,Sl. 149-16R. .(. A ~ c h . p mSW. D~V. P ~them.I comm ~~ ~~ ~ ~M ~ ~ ~ ~ ~t1968.~ I ,~ t 191-198. 5. IUI'AC Mseromolecular Diu. Comm. Macromolecular Nomenclature. Pure A p d r h e m ,976, +%373-385. 6. Rillmeyer, F.W., Jr. Textbook of Polymer S r i r n t c 3rd ed.: Wiley-Interscience: New York. 1884. 7. Rsdriyuer, F.P~inciplaso l P d y m s r Syslema, 2nd ed.; McGraw-Hill: New York, 1982. 8. Seymo~tr.R.S.;Carrxher,C.E..Jr.Polym~rChemirfry'Anlnlroduetion:Dekker.New Vork. 1981 s. Allcnck. H. R.; Lampe, F. W. Conhmpomry Polymer Chemistry; Pientic%Hall: New Ysrk. 1981. Phyairol Polymer Scirncs; Wiley.lnterseienee: New ,a Sperling, L. H. York, 19ffi.
Volume 64
Number 1 January 1987
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