Cationic cyclopolymerization of divinyl ethers with norbornane-, norbornene-, or adamantane-containing substituents: Synthesis of cyclopoly(divinyl ether)s with bulky rigid side chains leading to high glass transition temperature

Cationic cyclopolymerizations of 2,2-bis(vinyloxymethyl)bicyclo[2.2.1]heptane (1), 5,5-bis(vinyloxymethyl)-2-bicyclo[2.2.1]heptene (2), and 2,2-bis(vinyloxymethyl)tricyclo[3.3.1.1]3,7decane (3), divinyl ethers with a norbornane, norbornene, or adamantane unit, respectively, were investigated with the HCl/ZnCl2 initiating system in toluene and methylene chloride at 30 degrees C. All the reactions proceeded quantitatively to give gel-free, soluble polymers in organic solvents. The number-average molecular weight (Mn) of the polymers increased in direct proportion to monomer conversion and further increased on addition of a fresh monomer feed to the almost completely polymerized reaction mixture. The contents of the unreacted vinyl groups in the produced soluble polymers were less than approximate to 10 mol %, and therefore, the degree of cyclization of the polymers was determined to be over approximate to 90%. These facts show that cyclopolymerization of 1, 2, and 3 exclusively occurred and the poly(vinyl ether)s with the cyclized repeating units and polycyclic pendants were obtained with their molecular weights being regulated. BF3OEt2 initiator also caused cyclopolymerization of 1, 2, and 3 to give the corresponding high-molecular-weight cyclopolymers quantitatively. Glass transition temperatures (Tg's) of poly(1) and poly(2) were 165180 degrees C, and Tg's of poly(3) were 211231 degrees C; these values are very high as vinyl ether polymers. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2445-2454