High Performance Polymers, 2nd Edition

182 HIGH PERFORMANCE POLYMERS

or the corresponding alkali metal derivative con-

tains strong electron-withdrawing groups. This may

result in lower molecular weight polymers or slow

reaction rates. Therefore, the aromatic dihydroxy

compound should be a rather weakly acidic phenol,

such as 2,2-bis-(4-hydroxyphenyl)-propane, 1,1-bis-

(4-hydroxyphenyl)-2-phenyl ethane, and bis-(4-

hydroxyphenyl)-methane.

In the bis-(halophenyl)-sulfone, the sulfone group

activates the halogens toward the condensation reac-

tion. For this reason, it is preferred that the aromatic

rings do not contain electron supplying groups on

the same ring where the halogen is bonded. Several

examples of how to prepare PESs are given in the lit-

erature [26].

Poly(biphenyl ether sulfone)s