Synthesis and reactions of polymers with photoactive terminal groups—3. The use of radical promoted cationic polymerization for the synthesis of poly(n-butyl vinylether) with n-acyl dibenz(b, f)azepine terminal units

✍ Scribed by Yusuf Yagci; Wolfram Schnabel; Anthony Ledwith

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 252 KB
• Volume: 23
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(87)90116-9

✦ Synopsis

The free radical promoted cationic polymerization of n-butyl vinyl-ether (BVE) was achieved by the thermal decompositon of N-[4,4-azobis-(4-cyanopentanoyl)]-bisdibenz(b, f)azepine (ADBA) in the presence of diphenyliodonium hexafluorophosphate (Ph2I+PF6) or silver hexafluorophosphate (AgPF6). Polymer samples prepared in the presence of AgPF 6 contained a significant number of terminal dibenzazepine units. Chain extension via dimerization of the dibenzazepine units occurred upon irradiating these polymers with u.v. light (2 = 366 nm) in CH2CI 2 solution containing a triplet sensitizer (benzophenone or benzil), Polymer samples prepared in the presence of the iodonium salt contained only a very small fraction of macromolecules having dibenzazepine end-groups and were, therefore, not appropriate for the chain extension procedure.