Pressure-sensitive adhesives based on acrylated epoxidized linseed oil: A computational approach

The nature of the usage of pressure-sensitive adhesives (PSAs) in food packaging and healthcare industries demands them to be biodegradable and biocompatible. In this investigation, a novel renewable class of PSA is proposed wherein the low Tg monomer of commercially available PSAs (2-ethylhexyl acrylate (2-EHA)) is replaced with bio-sourced acrylated epoxidized linseed oil (AELO). For this, molecular dynamics simulations were employed to intensively investigate the potential of such green PSAs by estimating different surface properties and mechanical performance. The basic polymer properties such as density, solubility parameter and glass transition temperature (Tg) were found to be in good agreement with previously reported literature, thereby, validating the simulation protocols adopted. The insignificant change in Tg with the addition of AELO suggests good processability well below room temperature. The torsion and van der Waals' energies displayed transition peaks close to Tg, which make them significant contributors toward Tg. The increase in AELO content helped in achieving substantial enhancement in surface energy and substrate adhesion. The in-depth analysis helps to rationalize the marginal and significant increase of acrylate and hydroxyl groups respectively, contributed to enhance the surface properties. An increase in shear and bulk modulus was observed on increasing AELO concentration due to intra- and inter-molecular interactions between polar groups. This study paves the way for designing novel bio-based PSAs which have immense potential in the healthcare and food packaging industries.