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The use of carbon black-supported sulfuric acid to initiate the cationic polymerization of cyclic ketene acetals

โœ Scribed by Peter C. Zhu; Charles U. Pittman Jr.


Publisher
John Wiley and Sons
Year
1996
Tongue
English
Weight
643 KB
Volume
34
Category
Article
ISSN
0887-624X

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โœฆ Synopsis


Stable polymers were made by the cationically initiated 1,2-polymerization of cyclic ketene acetals employing heterogeneous, activated carbon-supported sulfuric acid catalysts. A methodology has been established for the preparation of the carbon black of different acidic strengths. By adjusting either the acid strength or the amount of carbon black used, cyclic ketene acetals with different activities can be polymerized efficiently to form stable high molecular weight polymers. This methodology will be a useful tool for polymerization, copolymerization, and studies of the relative reactivities of the cyclic ketene acetals. The polymer structures were determined by FTIR, I3C-NMR, and 'H-NMR studies. 0 1996 John Wiley & Sons, Inc. Keywords: activated carbon carbon black carbon black-supported sulfuric acid cationic polymerization 1,2-polymerization of cyclic ketene acetals cyclic ketene acetals cationic initiators catalyst heterogeneous catalysis * Taken, in part, from Ref. 1.


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Ring opening during the cationic polymer
โœ Peter C. Zhu; Zhihong Wu; Charles U. Pittman Jr. ๐Ÿ“‚ Article ๐Ÿ“… 1997 ๐Ÿ› John Wiley and Sons ๐ŸŒ English โš– 740 KB

The stable cyclic ketene acetal, 2-metbylene-1,3-dioxepane, 7, has been polymerized cat ionically in pentane, CHzClj and THF at 25ยฐC to form a polymer which is composed of both ring-opened (40-50% ) and ring-retained (50-60%) structures. Init iatiorr was catalyzed by using H2S0, -supported on activa