Addition-fragmentation type initiation of cationic polymerization using allyloxy-pyridinium salts

✍ Scribed by Bacak, Vildan; Reetz, Ivo; Yagci, Yusuf; Schnabel, Wolfram

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 240 KB
• Volume: 47
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199811)47:3<345::aid-pi67>3.0.co;2-5

✦ Synopsis

Allyloxy-pyridinium salts with various substituents on the allylic moiety are shown to be very efficient coinitiators in radical promoted cationic polymerization of cyclohexene oxide. Depending upon the radical initiator chosen, cationic polymerizations may be initiated by either heat or light. For the most part, the mechanism of initiation involves the addition of free radicals formed by the radical initiator, and a subsequent fragmentation of the energy-rich intermediate yielding initiating pyridinium type radical cations. In additionÈ fragmentation polymerization, the substituent at the allylic moiety does not sig-niÐcantly inÑuence the polymerization rate, thus implying that fragmentation is the rate determining step. In some cases, oxidation of the primarily formed free radicals contributes to the formation of initiating species. The salts under investigation are also able, to various extents, to initiate cationic polymerization upon external stimulation (heating or UV irradiation) without added radical initiators.

Society of Chemical Industry ( 1998