Title

Water-soluble polymers .72. Synthesis and solution behavior of responsive copolymers of acrylamide and the zwitterionic monomer 6-(2-acrylamido-2-methylpropyldimethylammonio) hexanoate

Document Type

Article

Publication Date

1-30-1997

Department

Polymers and High Performance Materials

Abstract

A novel carboxybetaine monomer, 6-(2-Acrylamido-2-methylpropyldimethylammonio) hexanoate (AMPDAH), has been synthesized and copolymerized with acrylamide in an aqueous NaBr solution. The feed ratio of AM (M(1)) : AMPDAB(M(2)) was varied from 98.5 : 2.5 to 0 : 100 mol %. The polymerizations were carried out to 20-30% conversion. Copolymer compositions were determined with C-13 NMR by integration of the amido carbonyl resonances. Reactivity ratios determined from the nonlinear least-squares method gave values of r(1) = 0.98 and r(2) = 0.85, indicating random incorporation of the comonomers into the final copolymer. Molecular weights ranged from 7.3 to 4.7 X 10(6) g/mol. The solubility behavior of the copolymers is dependent on the mol % AMPDAH incorporated into the copolymers. When 25 mol % or more is incorporated, the copolymers are only swellable in aqueous media and attempts to solubilize these systems were unsuccessful. AMPDAH incorporation of 10 mol % or less resulted in copolymers soluble in aqueous media under a variety of conditions. The viscometric properties of copolymers with 10 mol % or less is reported as a function of pH and added electrolytes. At high pH in deionized water, the polyzwitterions show both inter- and intramolecular associations, which are disrupted by the addition of sodium chloride. In deionized water, as the pH of the aqueous medium is lowered, the copolymers exhibit dramatic increases in viscosity as the carboxylate groups are protonated and charge-charge repulsions of the quaternary ammonium groups induce polyelectrolyte behavior. (C) 1997 John Wiley & Sons, Inc.

Publication Title

JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY

Volume

35

Issue

2

First Page

243

Last Page

253