Chemically Recyclable and Tunable Polyolefin-Like Multiblock Copolymer Adhesives

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Chemistry

Background:

• Hot-melt adhesives like poly(ethylene-co-vinyl acetate) (EVA) and polyurethanes are crucial for multilayer products but pose recycling challenges due to poor chemical recyclability and de-bonding.
• Current adhesives complicate waste management and hinder the development of circular economy models in packaging and construction.

Purpose of the Study:

• To develop tunable, chemically recyclable hot-melt adhesives based on polyolefin-like multiblock copolymers.
• To investigate the structure-property relationships governing the adhesive performance and recyclability of these novel materials.

Main Methods:

• Synthesized multiblock copolymers with controlled incorporation of crystalline hard blocks, amorphous soft blocks, and varying ester content.
• Characterized adhesive properties, including adhesion strength (up to 6.80 MPa), and evaluated de-bonding and chemical recycling processes.
• Demonstrated the application of these adhesives in multilayer film structures.

Main Results:

• Achieved tunable adhesive properties by regulating copolymer composition, resulting in strengths significantly higher than conventional EVA.
• Successfully demonstrated facile de-bonding, recovery, and chemical recycling of the adhesives, yielding virgin-quality material.
• Established a modular adhesive platform with tunable adhesion from low to high ranges.

Conclusions:

• The developed multiblock copolymers offer a sustainable alternative to conventional hot-melt adhesives, enabling chemical recyclability and repeated reuse.
• This platform provides a versatile solution for designing high-performance adhesives with tailored properties for diverse applications.
• The study highlights the potential for advanced polymer design to address critical recycling challenges in the materials industry.