Post-polymerisation oxyfunctionalisation of styrene and butadiene-based (co-)polymers using a homogeneous manganese...

Area of Science:

• Polymer Chemistry
• Catalysis
• Materials Science

Background:

• Post-polymerization modification offers a route to functional polymers not achievable through direct synthesis.
• Commodity hydrocarbon polymers like polystyrene and polybutadiene lack inherent functionality, limiting their applications.
• Developing efficient and green methods for polymer functionalization is crucial for advanced materials development.

Purpose of the Study:

• To demonstrate the oxyfunctionalization of styrenic and rubbery polymers using a manganese-based catalyst.
• To explore the versatility of the catalytic system for modifying various polymer types and C-H/C=C bonds.
• To investigate the potential for controlled polymer degradation into dialdehyde oligomers post-functionalization.

Main Methods:

• Utilized a homogeneous manganese catalyst (MnTACN) with hydrogen peroxide as a green oxidant.
• Applied the catalyst to various grades of polystyrene (PS) and polybutadiene (PBD) homopolymers, and styrene-butadiene-styrene (SBS) block copolymers.
• Characterized functionalized polymers using techniques like gel permeation chromatography (GPC) and analyzed thermal properties.

Main Results:

• Successfully introduced alcohol, ketone, and epoxide functional groups onto PS and PBD polymer backbones.
• Achieved high functionalization degrees: up to 5% for PS, 18% for PBD, and 11% for the butadiene component in SBS.
• Demonstrated random functional group distribution and potential for controlled backbone cleavage into dialdehyde oligomers.

Conclusions:

• The MnTACN catalyst system is versatile for oxyfunctionalizing diverse hydrocarbon polymers.
• Oxyfunctionalization can be coupled with controlled degradation, yielding valuable oligomeric products.
• Functionalized polymers exhibit largely unchanged thermal properties, with minimal backbone alteration for PBD and low/mid M_w PS.