Reactivities towards the benzoyloxy radical: Two isomers of tetraphenylbuta-1,3-diene and a 1,3-isomer of distyrylbenzene

✍ Scribed by C.A. Barson; J.C. Bevington; S.W. Breuer

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 312 KB
• Volume: 29
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(93)90240-g

✦ Synopsis

Benzoyl peroxide, doubly labelled with carbon-14 and tritium, has been used at 60 ° to initiate polymerizations of methyl methacrylate (I) containing in turn the E,E-isomers of the following compounds:-l,l,4,4-tetraphenylbuta-l,3-diene (II), 1,2,3,4-tetraphenylbuta-l,3-diene (III) and 1,3-distyrylbenzene (IV). The relative numbers of benzoate and phenyl end-groups in each of the polymers were determined and used to compare the reactivities towards the benzoyloxy radical of l, II, lI! and IV; the relative rate constants for the additions of the radical appear to be 1.0, 29, 184 and 84 respectively but there is some doubt about the value for II. It is pointed out that, in certain systems, retardation in radical polymerization can be caused by an additive reducing the rate of initiation and not by it reacting with a growing polymer radical.