Preparation of amphiphilic acrylic acid copolymer and its application in humidity-sensitive coatings

A new kind of water-dispersed resin, amphiphilic acrylic acid copolymer resin was prepared by hydrophilic monomer, hydrophobic monomer, and functional monomer (diacetone acrylamide). The effect of acid value and diacetone acrylamide concentration on water solubility was investigated. It showed that the acid value should be greater than 100 mg KOH/g. The coating properties of the amphiphilic acrylic acid copolymer resin and its film were measured, which showed excellent properties in hardness, gloss, and water resistance. It was applied to prepare the humidity-sensitive coatings. The water absorption of humidity-sensitive coatings was 260%. It could increase indoor humidity or dehumidify in dry or moist environment. On the basis of scanning electron microscopy images, the mechanism of humidity-sensitive activity was also discussed. The humidity-sensitive exhibited humidity sensitivity and excellent humidity retention because fillers of porous structure combined with amphiphilic copolymer. It could be widely applied in indoor coating for controlling humidity. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 3109-3117, 2011