THE ASSOCIATION OF AQUEOUS PHENOLIC RESIN WITH POLYETHYLENE OXIDE ANDPOLY(ACRYLAMIDE-CO-ETHYLENE GLYCOL)

Comb copolymers formed from acrylamide and poly(ethylene-glycol) metha crylate macromonomer (PAM-co-PEG) were compared to poly(ethylene oxide ) (PEG) with respect to hydrogen bond complex formation with water-bor ne phenolic resins. The behaviors of the two types of high molecular w eight polyethers were similar. Complex formation gave a transient incr ease in viscosity followed by precipitation. Copolymers with pendant P EG chain lengths greater than or equal to 9 formed complexes with phen olic resin whereas PEG homopolymer with a molecular weight of 2000 did not form a complex. For both copolymer and high molecular weight PEG, the tendency of the complex to precipitate increased when the pH was decreased from 7 to 4. Acridine orange, a cationic dye, bound to the p henolic resin and, after the addition of PEG, yielded visible complex gels with diameters about 20 mu m. (C) 1995 John Wiley & Sons, Inc.