The Polymer Society of Korea

Abstract

Pressure sensitive adhesives are widely used in products including sticky notes, tapes, and labels. However, most commercial PSAs are derived from fossil resources, rely on tackifiers, and are non-degradable, raising environmental issues. Therefore, the design of sustainable PSAs with competitive adhesion performance without tackifiers remains a critical challenge. In this study, we report tackifier-free polyurethane PSAs derived from cardanol, a renewable byproduct from cashew nut shells. The adhesives achieved high adhesion strength without tackifiers or plasticizers. This performance is attributed to the unsaturated bulky alkyl chains of cardanol in combination with the hydrogen bonding of urethane linkages, as confirmed through thermal and rheological characterizations. Additionally, the adhesives exhibited rapid degradation under mild conditions. This work provides high performance, degradable PSAs from renewable feedstocks and contributes to sustainable adhesive development.