Thermally and base-triggered 'debond-on-demand' crosslinked polyurethane adhesives

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Chemistry

Background:

• Industrial applications require advanced materials with tunable properties.
• Growing demand for environmentally friendly materials necessitates degradable polymers.
• Existing adhesives and coatings lack efficient debonding mechanisms.

Purpose of the Study:

• To synthesize and characterize novel crosslinked polyurethanes (CEPUs).
• To investigate the mechanical, adhesive, and degradable properties of CEPUs.
• To demonstrate the 'debond-on-demand' capability of these new materials.

Main Methods:

• Synthesis of crosslinked polyurethanes using 2,2 -sulfonyldiethanol as a chain extender.
• Mechanical testing including tensile strength and elongation at break.
• Adhesion testing on various substrates, including aluminum.
• Depolymerization studies using tetrabutylammonium fluoride (TBAF).

Main Results:

• Achieved ultimate tensile strengths up to 42.68 MPa and elongation at break of 17.59 %.
• Demonstrated high adhesive shear strength, reaching 7.80 MPa on aluminum.
• Successfully triggered depolymerization and solubilization using TBAF.
• Showcased rapid 'debond-on-demand' adhesion with up to 34% loss in shear strength on aluminum within 30 minutes.

Conclusions:

• The developed CEPUs exhibit a promising combination of strong adhesion, tunable mechanical properties, and rapid degradability.
• The use of 2,2 -sulfonyldiethanol enables the creation of environmentally conscious polyurethanes.
• These materials are suitable for applications requiring depolymerisable coatings and 'debond-on-demand' adhesives.