| Abstract: | This article describes the use of cobalt‐mediated catalytic chain transfer in aqueous solution under fed conditions for the preparation of macromonomers of acidic, hydroxy, and zwitterionic functional monomers. Use of a batch reaction leads to hydrolysis of catalyst, a mixture of mechanisms and poor control of the reaction. A feed process is described that adds catalyst as a solution in monomer over the course of the reaction. The feed process is applied to a range of monomers of methacrylic acid ( 2 ), 2‐aminoethyl methacrylate hydrochloride ( 3 ), 2‐hydroxyethyl methacrylate ( 4 ), 2‐methacryloxyethyl phosphoryl choline ( 5 ), glycerol monomethyl methacrylate ( 6 ), and 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐D ‐glucofuranose ( 7 ). Use of the feed process for water‐soluble monomers in conjunction with 1 as a catalytic chain‐transfer agent gives high‐conversion, > 90%, water‐soluble macromonomers. The number‐average molecular mass (Mn was determined by integration of the 1H NMR spectrum comparing the vinylic end group with the remainder of the backbone. Pseudo‐Mayo plots were constructed by measuring the Mn at high conversion as a function of monomer]/catalyst] to give observed chain‐transfer constants of 1120, 958, and 1058 for 4, 6, and 2, respectively. All products were obtained as relatively high‐solid, homogeneous, low‐viscosity aqueous solutions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2378–2384, 2001 |
