Other Specific Chemical and Physical Methods

Depending upon the system under investigation, various specific tricks have been contrived for elucidating certain aspects of the mechanism of a cationic polymerisation. Since these ideas and methods are scattered throu the literature, it is impossible to refer to all of them briefly and systematically. We will give just a few examples in this section and discuss the other important cases in the appropriate contexts throughout this review. 

The use of labelled molecules to clarify a reaction mechanism has often been -plied to initiation of cationic polymerisation. The most successfiil results have been obtained by Russell et al. in the context of water cocatalysis in the polymerisation of isobutene by stannic chloride. 

Saegusa et al. have recently developed a method for killing a cationic polymerisation with phenoxide ions in order to count the number of active chains present in certain systems  

Cheradame et have looked into the formation of titanium tetrachloride-indene addition products to prove the occurence of direct initiation. 

One of the best studies of the relationship between polymer structure, end groups and molecular-weight distribution, and the mechanism of its formation is still an old classical study by Brown andMatheson on the system styrene-trichloroacetic acid. 

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