Enhanced adhesion to low-surface-energy substrates using polyurethane acrylate/polyacrylate interpenetrating network pressure-sensitive adhesives

Abstract

In modern industrial applications, achieving strong adhesion to low surface energy materials, such as polyethylene, polypropylene, and polytetrafluoroethylene, is a significant challenge. This is primarily due to their inherent chemical inertness and weak interfacial interactions. To address this challenge, this study developed a novel pressure-sensitive adhesive with an interpenetrating network (IPN) structure. This was achieved by synthesizing linear polyethylene glycol-based polyurethane acrylate (PUA) oligomers and combining them with polyacrylate pressure-sensitive adhesives (PSA) to form the IPN structure. By adjusting the content of PUA, the viscoelasticity, mechanical, thermal, and adhesive properties of the PSA-PUA system were successfully optimized. The results demonstrate that the PSA-PUA20 exhibits excellent adhesion performance on polyethylene(PE) substrates, with a peel strength of 364.75 N/m and a loop tack of 4.03 N. Compared to polyacrylate pressure-sensitive adhesives (PSA), these values represent increases of 240.25 % and 46.58 %, respectively. Additional lap shear tests further confirmed that the PSA-PUA20 enables cyclic adhesion on polytetrafluoroethylene (PTFE) substrates. A mechanistic analysis reveals that the incorporation of PUA alters the surface energy of the adhesive, improving its spreading properties on low surface energy materials. Additionally, it strengthens the hydrogen bonds and van der Waals forces between molecular chains, significantly improving the cyclic shear performance and adhesion performance on low surface energy substrates. Furthermore, the PSA-PUA adhesive exhibits excellent antioxidant and thermal stability, offering a promising solution for the design of high-performance PSAs.