Chemistry Reference
In-Depth Information
O
O
O
Ph
Ph
O
O
O
O
Ph
O
Ph
H
H
CC
H
x
Polystyrene
The benzoyl radical reacts with styrene to form the benzylic radical. This
reacts with a second styrene molecule to form the dimer. The reaction con-
tinues through a series of propagation steps to form ultimately polystyrene.
Rather than writing the repeating structure over and over, it is written in
parentheses with a letter such as m, n, x, y, or z to indicate an unknown
number of repetitions. If this method is used to write the dimer, the number
2 would be used in place of x. Note that all 16 atoms of styrene (C
8
H
8
)are
incorporated into the polymer.
Radical polymerization of styrene is the predominant method of
polystyrene manufacture, but styrene can be polymerized by other means.
Styrene can be polymerized by an anionic mechanism, for example by
treatment with a minor amount of butyl lithium to initiate the reaction.
Li
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