Copolymerization of norbornene with ω‐alkenylaluminum as a precursor comonomer for introduction of carbonyl moieties

Abstract

ABSTRACTNorbornene copolymers functionalized with methyl ester group or carboxy group are facilely synthesized by the copolymerization of norbornene and 7‐octenyldiisobutylaluminum (ODIBA) with ansa‐dimethylsilylene(fluorenyl)(t‐butylamido)dimethyltitanium (1) activated by Ph3CB(C6F5)4, and the sequential CO2/methanolysis reactions or CO2/hydrolysis reactions, respectively. The methanolysis and the hydrolysis are simply switched by engaging acidic methanol or acidic aqueous acetone as the quenching/washing solution, respectively. Meanwhile, the increase of ODIBA in the copolymerization abruptly decreases the yield and number–average molecular weight (Mn) of the product. However, the addition of triisobutylaluminum (8 mM) and the use of excess Ph3CB(C6F5)4 (twofold of 0.4 mM of 1) significantly increase the yield, accompanying the increase in the Mn and the narrowing of the molecular weight distribution (Mw/Mn), especially in the case of the use of excess Ph3CB(C6F5)4. The yield (g polymer/g monomers), Mn, and Mw/Mn reach up to 0.82, 341,000, and 1.46, respectively, at a copolymerization condition. The carboxy groups in the norbornene copolymers are controlled in the range of 0–1.8 mol % in high polymer yields with high Mn and narrow Mw/Mn accompanied by the decrease in the contact angle with water from 104° to 89°. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5085–5090