Telechelic Oligomers Obtained by Iodine Transfer Polymerization

Telechelic Oligomers Obtained by Iodine Transfer Polymerization 

More recently, several investigations have shown that ITP can produce telechelic oligomers. The degenerative transfer process then requires the use of diiodide compounds instead of the iodide compounds usually employed in ITP. Noteworthy, the Dupont [231] and Ausimont [232] companies were first attracted by this concept (using IC4F8l as the transfer agent) in the CRP of 

For n = 2 this sequence is not possible because the deiodination of the precursors occurs  

To get the diiodo telechelic structure, the authors used iodoform and methylene iodide as degenerative CTAs. SET involves the production of radical ions generating free radicals and anions or cations. Iodoform and methylene iodide can be activated both by degenerative transfer mediated by the growing PVC radicals and by SET. The reaction may be catalyzed by sodium dithionite (Na2S204). These catalyzed reactions allow the suppression of side reactions but also the scavenging of oxygen. The LRP of vinyl chloride resulted in diiodo PVC with Mn of 6000- 10 000 g mol 1 and with PDI of about 1.6. 

However, the chain-end functionality remained an iodine atom. Further investigations to replace the iodine atom by an interesting polycondensable function were undertaken by various authors. 

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