Biodegradable Thermoplastic Polyurethane Pressure Sensitive Adhesives Synthesized From Polyester/Polyether Polyol

Renewable and degradable pressure-sensitive adhesives (PSAs) have emerged as promising green alternatives in the adhesive industry, addressing both petroleum resource depletion and plastic pollution challenges. This work is to provide a design and preparation of high-performance biodegradable bio-based thermoplastic polyurethane pressure-sensitive adhesive(TPU-PSAs) to solve the problem that most PSAs are nondegradable, nonrenewable, and nonrecyclable. Through a solvent-free one-step polymerization process, we synthesized bio-based TPU-PSAs using polylactide diol (PLA), polycaprolactone diol (PCL), and polytetramethylene ether glycol (PTMEG) polyols with varying NCO/OH ratios. Through the correlation analysis of microphase separation morphology, viscoelastic response, and macroscopic adhesion behavior, the structure-performance relationship of the system was established, which promoted the rational design of sustainable adhesives. Notably, HS (30)/0.8 (NCO/OH = 0.8) demonstrated exceptional peel strength (7.5 N/cm) coupled with substantial biodegradability (56.4% degradation within 8 weeks). Meanwhile, HS (30)/1 (NCO/OH = 1) exhibited superior shear resistance (368 kPa on glass substrates) without requiring cross-linking agents. These TPU-PSAs showcase a unique combination of tunable viscoelastic properties through controlled microphase separation, positioning them as promising candidates for sustainable adhesive applications that demand biodegradability, recyclability, and renewability.