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

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, ¹³C-NMR, and ¹H-NMR studies. © 1996 John Wiley & Sons, Inc.