Bottlebrush Polyolefin Sulfones as Triggerable and Degradable Pressure-Sensitive Adhesives

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Chemistry

Background:

• Bottlebrush polymers possess unique properties due to their architecture, enabling applications as functional materials like elastomers and pressure-sensitive adhesives (PSAs).
• Existing bottlebrush PSAs often face limitations such as crosslinking, thermal instability, or insufficient molar mass, hindering their widespread adoption.
• The development of high-performance, degradable adhesives is crucial for reducing environmental impact and enabling sustainable material lifecycles.

Purpose of the Study:

• To synthesize high molar mass, degradable bottlebrush polymers using a novel copolymerization approach.
• To incorporate various side chains into the bottlebrush architecture, creating versatile functional materials.
• To evaluate the adhesive properties and degradability of the synthesized bottlebrush polymers for potential PSA applications.

Main Methods:

• Alternating free-radical copolymerization of sulfur dioxide (SO2) and norbornene-based macromonomers in a grafting-through approach.
• Synthesis of poly(olefin sulfone) bottlebrush polymers with high number-average molar masses (>1100 kg/mol) and backbone degrees of polymerization (>900).
• Incorporation of diverse side chains including polyacrylate, polymethacrylate, polystyrene, and poly(lactic acid).

Main Results:

• Achieved synthesis of bottlebrush polymers with exceptionally high molar masses, exceeding 1100 kg/mol.
• Demonstrated triggerable degradation of the bottlebrush polymers under mild alkaline conditions within hours.
• The synthesized bottlebrush polymer exhibited PSA behavior with a high peel strength of ~1200 N/m, surpassing commercial non-degradable PSAs.

Conclusions:

• A versatile method for synthesizing triggerable and degradable bottlebrush polymers was established.
• These novel polymers offer a promising route to high-performance, environmentally friendly adhesives with controlled end-of-life disposal.
• The developed bottlebrush polymers represent a significant advancement in sustainable adhesive technology.