RAFT copolymerization of amphiphilic poly(ethyl acrylate)-b-acrylic acid as a wetting and dispersing agent for aqueous strippable decontamination coatings

Abstract

The widely used indicator, 2-(5-bromo-2-pyridylazo)− 5-diethylaminophenol (Br-PADAP), can enable color tracing of radioactive contaminants when incorporated into strippable decontamination materials. However, its practical application is hindered by poor dispersion in aqueous substrates. To address this issue, this study prepared an amphiphilic diblock copolymer, PEA-b-PAA, using a one-pot synthesis method. Ethyl acrylate (EA) and acrylic acid (AA) were used as monomers, with S,S,S-trisulfanyl dibenzyl carbonate (DBTTC) serving as the initiator for reversible addition-fragmentation chain transfer (RAFT) polymerization. Test results demonstrated that block copolymers with EA:AA monomer ratios of 2:1, 1.5:1, and 1:1 effectively dispersed and stabilized the Br-PADAP indicator. Among these, the copolymer with a 1.5:1 monomer ratio, added at a concentration of 4%, improved the mechanical properties of the peelable decontamination material without compromising the color tracing function of Br-PADAP. This enhancement facilitates practical applications by enabling incorporation into aqueous peelable substrates, while maintaining the indicator’s color development mechanism. The resulting materials exhibit both effective decontamination and reliable color tracing capabilities.