Influence of Dioctyl Maleate Concentration on Performance Behavior of Water Based Pressure-sensitive Adhesives via Reversible Addition–Fragmentation Chain Transfer Emulsion Polymerization

Reversible addition–fragmentation chain transfer (RAFT)-mediated polymerization was successfully applied for the synthesis of pressure-sensitive adhesives (PSAs) of predetermined molar mass and of low polydispersity index (PDI). The performances of the adhesives were investigated by testing tack, peel, and shear resistance on seven different substrates (coated paper, uncoated paper, polyethylene terephthalate (PET), biaxially oriented polyethylene terephthalate (BOPP), aluminum strip, low linear density polyethylene (LLDPE), and low density polyethylene (LDPE). The influence of monomer composition on the adhesive performance was evaluated by varying the molar ratio of butyl acrylate (BA)/dioctyl maleate (DOM) while keeping the molar ratio of acrylic acid (AA) and 2-hydroxy ethyl acrylate (2-HEA) constant. As the DOM content increased, shear, peel strength, and loop tack were found to increase. It was noted that the adhesive properties of PSAs can be tailored by incorporating small amounts of hydrophobic DOM into the PSAs, which significantly increases the peel and shear strength of the resulting PSAs. Carboxyl terminated bifunctional trithiocarbonate RAFT agent possess the strong potential to polymerize hydrophobic DOM in aqueous phase and exhibit better living character with PDI less than 1.5.