Chemistry Reference
In-Depth Information
is a polysulfone. These polymers are generally made by reacting two monomers
with the elimination of a smaller molecule [reactions (1-1) and (1-7), for exam-
ple]. They are thus called condensation polymers (see also
Section 7.1
).
Condensation polymers are named by analogy with the lower-molecular-
weight esters, amides, and so on. Thus, since the names of all esters end with the
suffix -ate attached to that of the parent acid (e.g., 1-50)
CH
3
COCH
3
CH
3
O
1-50
is ethyl acetate, polymer 1-5 is named poly(ethylene terephthalate). The parent
acid here is terephthalic acid, which is the para isomer. (The ortho diacid is
phthalic acid and the meta isomer is isophthalic acid.) The alcohol residue must
be a glycol if the polymer is to be linear, and so it is not necessary to use the
word glycol in the polymer name. The word ethylene implies the glycol. Note
that the trade name is usually used for the monomers. Thus, structure 1-51 would
be named poly(tetramethylene terephthalate) or poly(butylene terephthalate)
rather than poly(1,4-butane terephthalate).
O
CH
2
CH
2
CH
2
CH
2
O
C
O
C
n
O
1-51
Polyamides are also known as nylons. They may be named as polyamides.
Thus 1-6 is poly(hexamethylene adipamide). This name indicates that the poly-
meric structure could be made by condensing hexamethylene diamine, H
2
N
(CH
2
)
6
NH
2
, and adipic acid, HOOC(CH
2
)
4
COOH. The dibasic acids are named
according to their trivial names: oxalic (HOOC—COOH), HOOC(CH
2
)COOH
malonic, HOOC(CH
2
)
2
COOH succinic, glutaric, adipic, and so on. (The mne-
monic is OMSGAPSAS: oh my, such good apple pie, sweet as sugar. We leave it
to the reader to fill in the trivial names after adipic, if and when they are needed.)
There is also an alternative numbering system for synthetic polyamides.
Polymers that could be made from amino acids are called nylon-x, where x is the
number of carbon atoms in the repeating unit. Thus, polycaprolactam (1-13) is
nylon-6, while the polymer from
-aminoundecanoic acid is nylon-11. Nylons
from diamines and dibasic acids are designated by two numbers, in which the first
represents the number of carbons in the diamine chain and the second the number
of carbons in the dibasic acid. Structure 1-6 is thus nylon-6,6. Nylon-6,6 and
nylon-6 differ in repeating unit length and symmetry and their physical properties
are not identical.
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