High Performance Polymers, 2nd Edition

110 HIGH PERFORMANCE POLYMERS

polymerization has been demonstrated to be a suitable

technique of polymerization.

With only one end cap, the PPE is integrated with

the styrene and acrylonitrile units to form a comb-

type structure with the PPE segments formingthe teeth

of the comb. Without end caps, the hydroxyl groups

on the PPE chains tend to inhibit the reaction of the

styrene monomers. Crosslinking can be expected to

increase with multiple functionalized PPE. Typically,

the amount of end-capped PPE introduced to the reac-

tion medium is 10–15%.

The glass transition temperatures of the copolymers

increase with increasing levels of PPE and range from

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