Analysis of the telomerization of methyl methacrylate by thioglycolic acid. Application to determining the probabilities of structures of synthesizedtelomers

This paper presents a new theoretical method for the determination of the P MMA telomers functionality in order to better control the telomerization re action. Telomers bearing a functional end-group are obtained by telomerizat ion of methyl methacrylate with thioglycolic acid, initiated either with 2, 2'-azoisobutyronitrile (AIBN) or with 4,4'-azocyanopentanoic acid (ACPA). I n both cases of initiation, the transfer constants of thioglycolic acid are determined and are respectively equal to 0.672 and 0.674. Then, these resu lts were applied to this new method so as to predict and quantify the sever al structures of telomers obtained above, This method is based on both cont ribution of termination and transfer to mercaptan in Mayo's law and allows to quantify all the kinds of macromolecules with their both extremities. Th e influence of the telogen amount vs the functionality of telomers, that of the initiator concentration and that of the nature of the initiator are in vestigated and underlined the importance of each factor. Finally, theoretic al telomer functionalities are compared with experimental ones by titration of acid functions and are in good agreement. [GRAPHICS]