Commodity Polymer Functionalization by a Combination of Hydrogen Atom Transfer Reversible Addition-Fragmentation...

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Chemistry

Background:

• Commodity polymers possess abundant C-H bonds, offering potential for upcycling and performance enhancement.
• Existing C-H functionalization methods often suffer from low efficiency (<20%) and limited functional group introduction per site.
• Low functional group density hinders significant improvements in polymer properties.

Purpose of the Study:

• To develop an efficient and versatile strategy for functionalizing commodity polymers.
• To overcome the limitations of low functional group content in previous C-H activation methods.
• To enable the upcycling of commodity polymers into high-performance materials.

Main Methods:

• Utilized a photocatalytic hydrogen atom transfer reversible addition-fragmentation chain transfer (HAT-RAFT) grafting polymerization.
• Employed C-H bonds of commodity polymers (polyethylene glycol, polypropylene oxide, polybutylene, polypropylene, polyvinylpyrrolidone) as initiating sites.
• Grafted pentafluorophenyl acrylate (PFA) to introduce activated pentafluorophenyl ester (PFE) side chains.

Main Results:

• Achieved living/controlled and temporally controllable grafting polymerization of PFA.
• Demonstrated an amplification effect, introducing tens of PFEs per activated C-H bond, significantly increasing functional group density.
• Confirmed high reactivity of introduced PFEs for subsequent functionalization via transesterification and amidation.

Conclusions:

• The HAT-RAFT strategy enables highly efficient functionalization of commodity polymers.
• The high density of PFE groups allows for versatile and mild post-polymerization modification.
• This approach provides a promising route for upcycling commodity polymers and enhancing their material properties.