Polymerization and copolymerization of functionalized 2‐alkoxy‐1‐methylenecyclopropanes to form new polymers having alkoxy substituents

The polymers with functionalized alkoxy groups and with narrow molecular weight distribution (M_w/M_n < 1.12) are obtained from the living polymerization of 2‐alkoxy‐1‐methylenecyclopropanes using π‐allylpalladium complex, (PhC₃H₄)Pd(μ‐Cl)]₂, as the initiator. The polymers with oligoethylene glycol groups in the alkoxy substituent are soluble in water, and hydroboration of the C?C double bond and ensuing addition of the OH groups to C?N bond of alkyl isocyanate produce the polymers with urethane pendant groups. The reaction decreases solubility of the polymer in water significantly. Di‐ and triblock copolymers of the 2‐alkoxy‐1‐methylenecyclopropanes are prepared by consecutive addition of the two or three 2‐alkoxy‐1‐methylenecyclopropane monomers to the Pd initiator. The polymers which contain both hydrophobic butoxy or tert‐butoxy group and hydrophilic oligoethylene glycol group dissolve in water and/or organic solvents, depending on the substituents. The ¹H NMR spectrum of poly( 1a ‐b‐ 1h ) (? (CH₂C(?CH₂)CHOBu)_n? (CH₂C(?CH₂)CH(OCH₂CH₂)₃OMe)_m? ) in D₂O solution exhibits peaks because of the butoxy and ?CH₂ hydrogen in decreased intensity, indicating that the polymer forms micelle particles containing the hydrophilic segments in their external parts. Aqueous solution of the polymer with a small amount of DPH (DPH = 1,6‐diphenyl‐1,3,5‐hexatriene) shows the absorbance due to DPH at concentration of the polymer higher than 5.82 × 10^?5 g mL^?1. Other block copolymers such as poly( 1b ‐b‐ 1h ) and poly( 1a ‐b‐ 1g ) also form the micelles that contain DPH in their core. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 959–972, 2009