Deconstructing Polymers Synthesized by Controlled Radical Polymerization

Controlled radical polymerization (CRP) is widely used to prepare a broad range of polymeric materials for diverse applications in various fields. One of the most important properties of CRP polymers is the ability to maintain high livingness throughout the polymerization. Although such high end-group functionality has been overwhelmingly exploited for chain extensions and block copolymer synthesis in thousands of publications, it has rarely been explored for the polar opposite: reversing controlled radical polymerization and regenerating the monomer. In this talk I will first discuss about a near-quantitative and catalyst-free depolymerization of various linear, bulky, cross-linked, and functional polymethacrylates made by reversible addition−fragmentation chain-transfer (RAFT) polymerization. Notably, the depolymerization product can be utilized to either reconstruct the linear polymer or create an entirely new insoluble gel that can also be subjected to depolymerization. As this approach only operates under very high dilution, I will then introduce a solvent-free chemical recycling methodology that efficiently operates for both ATRP and RAFT synthesized materials. However, both depolymerization reactions are uncontrolled in nature (i.e. rapid monomerization of activated chains), thus providing no handle over the molecular weight and limiting further applications. To address this, I will finally discuss a controlled depolymerization strategy that enables a linear decrease in molecular weight over time. Such gradual unzipping of polymer chains enables the structural characterization of various copolymers (i.e. AB diblock vs BA diblock vs statistical vs gradient) by facilitating the sequential release of monomers from the chain-end.

Speakers

Athina Anastasaki

KAUST

KAUST Research Centers

KCC Research Groups