Several monomers have been polymerized using %,l'-azobis(1-phenyl I-13C] ethane as initiator~ the initiator fragments incorporated in the polymers have been examined by 13C-N~. The chemical shift for the enriched site in the end-group depends upon the nature of the attached monomeric unit. It is con
Reactivities of monomers towards the 1-phenylethyl radical: Monomers with low ceiling temperatures
β Scribed by J.C. Bevington; D.A. Cywar; T.N. Huckerby; E. Senogles; D.A. Tirrell
- Publisher
- Elsevier Science
- Year
- 1990
- Tongue
- English
- Weight
- 372 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0014-3057
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β¦ Synopsis
Akstraet--The reactivities towards the 1-phenylethyl radical of 2-vinylnaphthalene and some monomers with low ceiling temperatures (~-methylstyrene, 2-isopropenylnaphthalene and ct-methoxystyrene) have been assessed by I aC-NMR examination of end-groups in terpolymers prepared at 100 Β° using t3C-enriched azobis-l,l'-phenylethane as initiator. In each case, acenaphthylene has been used with styrene (STY) or methyl methacrylate and a third monomer selected from the quoted list. The present and previous results suggest that, for many monomers, the reactivity towards the l-phenylethyl radical is very similar to that predicted from data on copolymerizations with STY, regarding the initiating small radical as a model for the polystyrene radical. There are appreciable differences between the observed and predicted relative reactivities in cases where either the eopolymerization of the monomer with STY may show quite pronounced penultimate group effects or the monomer has a low ceiling temperature.
π SIMILAR VOLUMES
Alrstraet--~3C-NMR spectroscopy has been used for examination of 2-cyano-2-propyl end-groups in copolymers of styrene (STY) with methacrylonitrile (MAN) and with vinyl acetate (VAC) prepared at 10@' using as initiator 2-cyano-2-propylazoformamide enriched in its methyl groups with carbon-13. It is d
l\*C-benzoyl peroxide has been used at 60 Β° to initiate polymerizations of vinyl formate, propionate, butyrate, benzoate and phenyl acetate at various concentrations in benzene. The relative numbers of benzoyloxy and phenyl end-groups in the various polymers have been determined; these numbers have
## Azobis(isobutyronitrile) and 2-cyano-2-propylazoformamide, both enriched with carbon-13, have been used to initiate copolymerizations of o<methoxystyrene (MOS) with methyl methacrylate. The copolymers have been examined by 13C-NMR so allowing study of the end-groups derived from the initiator.
Styrene (M1) has been copolymerized with 0-, m-and p-halostyrenes (M2) at temperatures between 40 and ll0~C, using azoisobutyronitrile as initiator; the halostyrenes were labelled with 14C in the fl-position. The compositions of the copolymers were determined by liquid scintillation counting. ## Si