Living Anionic Polymerization of 1-Cyclohexyl[3]dendralene

Anionic polymerization of 1-cyclohexyl[3]dendralene (1CH3D) proceeded with potassium naphthalenide (K-Naph) or diphenylmethylpotassium (Ph2CHK) in tetrahydrofuran (THF) at –78 °C. Poly(1CH3D)s with the predicted molecular weights and narrow molecular weight distributions (MWD, Mw/Mn < 1.1) were quantitatively obtained. The polymerization of 1CH3D was attempted using sec-butyllithium (s-BuLi) in toluene to investigate the effect of solvent polarity. Sequential copolymerization of 1CH3D and 2-vinylpyridine was conducted using Ph2CHK to afford a poly(1CH3D)-b-poly(2-vinylpyridine) with well-defined chain structures, indicating the living character of the polymerization. Various nuclear magnetic resonance measurements revealed that the microstructure of poly(1CH3D) prepared in THF consisted of the 4,6-structure (80%) and 4,3-structure (20%). Meanwhile, the 4,6-structure content reached 94% in the polymer obtained in toluene. These results indicate that 1CH3D underwent propagation not only via conjugated addition mode but also via vinyl addition mode. The hydrogenation of poly(1CH3D) having a high 4,6-structure (>91%) was attempted to obtain an alternating copolymer, poly(ethylene-alt-1-butenylcyclohexane). The poly(1CH3D)s showed glass transition temperatures between 1 and 16 °C and a cross-linking property by heating over 270 °C.