Radical initiators and their influence on the viscosity and molecular weight of acrylic polymers applied in pressure-sensitive adhesives

Acrylic polymers, which can be applied as pressure-sensitive adhesives (PSA), based on 2-ethylhexyl acrylate, methyl acrylate, and acrylic acid were synthesized in ethyl acetate using azoperoxyester radical initiators. First, the investigated azoperoxyesters were synthesized and isolated. In a second stage, the thermally activated azo groups initiated the radical polymerization of the acrylate monomers. The viscosity, molecular weights, and polydispersities of the synthesized acrylic polymers usable as PSA were evaluated. The newly synthesized radical azoperoxyester initiators were compared with the commercial azo-initiator azobisisobutyronitrile (AIBN).