Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
2-Isopropenyl-4-methylene-1,3-dioxolane (1) undergoes cationic polymerization in donative solvents without crosslinking to afford poly(ether-ketone) 2 having two unitstructures. When solvents having medium donor number (DN = 14,1-17,1), such as acetonitrile, dioxane, ethyl acetate, and propylene carbonate, were used, 2 was obtained in high yields. When solvents having DN (〉19,2), such as diethyl ether, DMF, and DMAc, were used, the rate of polymerization decreased considerably, although polymerization proceeded even in the most donative solvent, DMAc (DN = 27,8). The ratio of the unit-structures was independent of the solvent used. When ethanol was used as the solvent, ethoxyacetone and methacrolein were obtained instead of 2. It was concluded that hard nucleophiles such as ethanol attack at the α′-position of terminal oxyallyl cation, while soft nucleophiles such as monomer 1 attack at the α-or γ-position.
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