Synthesis and Optimization of a Four-component Acrylic-based Copolymer as Pressure Sensitive Adhesive

Apressure sensitive adhesive (PSA) based on acrylic monomers was synthesized.For this purpose a solution copolymerization process was conducted forpreparation of an acrylic copolymer containing 2-ethylhexylacrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA), glycidyl methacrylate (GMA) and vinyl acetate (VAc),using 2,2''-azobisisobutyronitrile (AIBN) as an initiator. The initial amounts of feedmonomers were constant in all formulations (2-EHA/VAc/ HEA/GMA; 67%, 28%, 4.9%,0.1% by weights). With variation of different parametric conditions such as reactiontimes (3.5, 6.5 and 9.5 h), temperatures (70, 80 and 90°C) and initiator concentrations(0.25, 0.5 and 1 wt%) the copolymerization reactions were optimized. The adhesiveproperties have been evaluated in terms of intrinsic viscosity, glass transitiontemperature (Tg), peel strength and tack value for all samples. It was observed that thetrends in peel strength and intrinsic viscosity variations are approximately correlatedwith the above changing parameters. The synthesized PSAs show good adhesiveproperties and could be easily peeled off from the surface without leaving any residueon the surface. These samples with satisfactory adhesion properties werecharacterized by Fourier transform infrared, proton nuclear magnetic resonancespectroscopy, differential scanning calorimetry and gel permeation chromatography.Based on the optimum time (3.5 h), temperature (70°C) and initiator concentration(0.5 wt%), a formulation with the best adhesion properties and high conversion (86%)was selected as the optimized PSA and it was compared with a commercialized PSAnamely Duro-Tak 2287.