436 Anionic Polymerization of 1,3-Butadiene Derivatives Containing Dialkylamide Groups. -Effect of Alkyl Groups On the Polymerization Behavior-

Friday, November 6, 2009: 11:00 AM
Pancho Villa (Camino Real Hotel)
Katsuhiko Takenaka , Department of Materials Science and Technology, Nagaoka University of Technology, Nagaoka, Japan
Tomoo Shiomi , Department of Materials Science and Technology, Nagaoka University of Technology, Nagaoka, Japan
Hiroki Takeshita , Department of Materials Science and Technology, Nagaoka University of Technology, Nagaoka, Japan

Previously, we have reported the free-radical1), RAFT2), and anionic3) polymerization of N,N-diethyl-2-methylene-3-butenamide (DEA), a 1,3-butadiene derivatives containing diethyllamide function. In this paper, we would like to report the anionic polymerization behavior of other monomers having different alkyl substituents, N,N-diisopropyl-2-methylene-3-butenamide (DiPA), 2-methylene-1-(piperidin-1-yl)but- 3-en-1-one (PiA), and 1-((2R,6S)-2,6-dimethylpiperidin-1-yl)-2-methylenebut-3-en-1-one (DMPA) together with the microstructure of the resulting polymers.

All the polymerizations were carried out in THF using potassium counter ion. Small amount of LiCl was added for the polymerization at elevated temperature.

Poly(DEA) of narrow molecular weight distribution was obtained if the polymerization was carried out at -78, or at 0 C in the presence of LiCl. However, the rate of polymerization was so slow at -78 C that it took 720 h to get polymer of high molecular weight. If the polymerization temperature was raised to 0 C, only low molecular weight oligomer was formed by chain transfer reaction. Such a side reaction was suppressed if the polymerization was carried out at 0 C in the presence of LiCl, giving polymer of predictable molecular weight with narrow molecular weight distribution. In the case of DiPA and DMPA, monomers having bulky N-alkyl substituents, the rate of polymerization was much slower under similar condition. Conversion in the polymerization of DiPA leveled off at 0 C presumably due to equilibrium by the ceiling temperature. Polymerization of PiA proceeded much faster than the other monomers. Microstructure of the resulting polymer was a complicated mixture of 1,4-E, 1,4-Z, and 1,2.