Chlorosulfonated Poly(propylene carbonate)-Based Pressure-Sensitive Adhesives with Improved Thermal Stability and Peel Strength

The challenge of pressure-sensitive adhesives (PSAs) is to develop biodegradable PSAs with prominent thermal stability and considerable peel strength. To overcome this drawback, we designed and synthesized a series of 4,4′-diphenylmethane diisocyanate (MDI)-modified chlorosulfonated poly(propylene carbonate)s (CSPPC-MDIs) using a solvent-free method. We found that the introduction of MDI can effectively increase the molecular weight, T g, and thermal stability, demonstrating that MDI acts as both a capping reagent and chain extender. Rheology profiles, tack test and peel test results demonstrate that CSPPC-MDIs exhibit higher adhesion properties and peel strengths than original CSPPC. Furthermore, the adhesive and cohesive properties of CSPPC-MDIs can be controlled by tuning the MDI feed ratios. The CSPPC-MDI-3.0 (the reaction product of CSPPC and 3 wt % MDI) has a prominent peel strength (9.1 ± 0.1 N/cm) and biodegradable features compared to commercial PSAs such as 3M 810, 3M 2929, and AveryDennison 5078A, indicating that CSPPC-MDIs can be used as a better candidate for high-performance PSAs in the future.