Completely Recyclable Monomers and Polycarbonate: Approach to Sustainable Polymers

Abstract

It is of great significance to depolymerize used or waste polymers to recover the starting monomers suitable for repolymerization reactions that reform recycled materials no different from the virgin polymer. Herein, we report a novel recyclable plastic: degradable polycarbonate synthesized by dinuclear chromium-complex-mediated copolymerization of CO with 1-benzyloxycarbonyl-3,4-epoxy pyrrolidine, a meso-epoxide. Notably, the novel polycarbonate with more than 99 % carbonate linkages could be recycled back into the epoxide monomer in quantitative yield under mild reaction conditions. Remarkably, the copolymerization/depolymerization processes can be achieved by the ON/OFF reversible temperature switch, and recycled several times without any change in the epoxide monomer and copolymer. These characteristics accord well with the concept of perfectly sustainable polymers.

Depolymerization of End‐of‐Life Poly(lactide) via 4‐Dimethylaminopyridine‐Catalyzed Methanolysis

“…An interesting alternative can be the chemical recycling via depolymerization‐polymerization processes, the first one allows the formation of low‐molecular weight valuable monomers by selective degradation of the polymer chain (depolymerization step) (Scheme ) . This can be considered advantageously since the monomers can be applied as feedstock for new high‐quality polymers (polymerization step) and therefore a recycling of the polymer is reasonable . Interestingly, the amount of cultivable acreage needed for bioplastic or bio‐based plastic production can be reduced.…”

Living Coordination Polymerization of a Six‐Five Bicyclic Lactone to Produce Completely Recyclable Polyester

“…Chemically recyclable polymers [1][2][3][4][5][6][7][8][9][10][11][12] have attracted increasing attention in recent years because they allow for recovery of the building block chemicals via depolymerization or creative repurposing through generation of value-added materials,t hus offering af easible solution to the end-of-use issue of polymeric materials and providing ac losed-loop approach towards ac ircular materials economy. [13] However, three key challenges still remain before this approach becomes technologically and economically competitive: energy input, depolymerization selectivity,a nd depolymerizability/performance tradeoff.…”

Catalyst‐Sidearm‐Induced Stereoselectivity Switching in Polymerization of a Racemic Lactone for Stereocomplexed Crystalline Polymer with a Circular Life Cycle

“…Chemically recyclable polymers [1][2][3][4][5][6][7][8][9][10][11][12][13] have lately attracted growing attention because their building block chemicals,o r monomers,c an be recovered for the production of virgin plastics with the same qualities as the original, thus offering af easible solution to the end-of-use issue of polymeric materials and providing ac losed-loop approach towards acircular materials economy. [14] However, there is aparadox between the ability to depolymerize and performance,where polymers that can be readily depolymerized back to monomers often lack physical properties and mechanical strengths to be widely useful, and vice versa.…”