Energetics of Cationic Polymerization

Having established a kinetic scheme, an explanation for the increase in overall rate with decreasing temperature is possible. The rate is proportional to (kjk lk ), so the overall activation energy E is given by 

The chain length, on the other hand, will always decrease as the reaction tran-perature rises becanse E, is always greater than Ej,. 

A telechelic polymer is defined as a relatively low-molar-mass spedes (M 20,000), with functional end groups that can be used for further reaction to synthesize block copolymers or for network formation. Cationic polymerization methods can be used to prepare these fimctionalized polymers using the initiator-transfer, or Inifer, technique perfected by Kennedy. If the initiating catalyst-cocatalyst system is prepared from a Lewis acid and an alkyl or aryl halide, i.e.. 

The terminal chlorine can then be converted by subsequent reactions into other useful functional groups. 

Bifunctional telomers can also be prepared, and these functional polymers can be used to form block copolymers using coupling reactions. 

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