WATER-SOLUBLE COPOLYMERS .46. HYDROPHILIC SULFOBETAINE COPOLYMERS OF ACRYLAMIDE AND 3-(2-ACRYLAMIDO-2-METHYLPROPANEDIMETHYL-AMMONIO)-1-PROPANESULPHONATE

The free radical copolymerization of acrylamide (AM) with 3-(2-acrylamido-2-methylpropanedimethylammonio)-1-propanesulphonate (AMPDAPS) has been studied in the range from 99 to 25% AM in the feed. Copolymer compositions obtained by elemental analysis and C-13 n.m.r. reflect the monomer feed concentrations. The value of r1r2 has been determined to be 0.60 for the AM-AMPDAPS pair. Copolymer microstructures, including run numbers and sequence distributions, were calculated from the reactivity ratios. Molecular weights for the series range from 3.0 x 10(6) to 21.5 x 10(6) g mol-1. Second virial coefficients decrease from 2.67 to 0.21 ml mol g-2 as charge density increases. Intrinsic viscosities decrease with increasing AMPDAPS content, but increase with increasing temperature (in the range of 25-60-degrees-C) and added electrolytes (NaCl and/or CaCl2). The solution behaviour of the homopolymer of AMPDAPS is independent of pH. The observed properties are consistent with the charge density of the polymers and the sulphobetaine structure of the AMPDAPS monomer.