Combined computational and experimental approach for bio-sourced monomers to design green pressure-sensitive adhesives

Abstract

The food packaging and healthcare industries have extensively demanded eco-friendly pressure-sensitive adhesives (PSAs) owing to their inherent renewability, sustainability and adhesion properties. In the present research, linseed oil derivatives have been used to synthesize bio-based PSAs by replacing petro-based low T_g monomers. A dual approach consisting of computational and experimental studies has been conducted to explore the potential of acrylated epoxidized linseed oil (AELO) and acrylated epoxidized methyl ester (AEME) as low T_g resins to develop bio-based PSAs. The thermal studies revealed that poly (AELO) and poly (AEME) are thermally stable up to 610 K and 577 K, respectively. The rheology of these resins suggests that AEME would be easily processable, while the addition of diluents to AELO can improve its processing significantly. The T_g values from DSC thermograms and simulation studies for poly (AELO) and poly (AEME) were in close proximity and met the prerequisite of low T_g monomers, thereby verifying the simulation protocol adopted. Further, surface energy and interaction energy with three different substrates were estimated to understand and compare the adhesion behavior of the synthesized resins. The potential applications of these bio-resins in healthcare and food packaging industries have been explored by estimating the binding strength with human skin and polypropylene (PP), respectively. An increment of ∼37% and ∼809% was observed in the interaction energy of poly (AELO) with human skin and PP as compared with the conventional poly (2-ethylhexyl acrylate (2-EHA))-based systems, respectively. The adhesion strength was found to be 38.2 and 31.5 N m⁻¹ for cured samples of poly (AELO) and poly (AEME), respectively, which are comparable to various commercially available PSAs. This research provides a path for exploring the potential of linseed oil derived AELO and AEME to formulate PSAs with desirable properties for healthcare and food packaging industries.