Base-Catalyzed Degradation of Vinyl Polymers via Generation of Anionic Species from C–H Bonds on the Backbones

 Vinyl polymers are widely used in various applications due to their high stability. however, their low degradability poses a significant environmental concern. Most approaches to degrade vinyl polymers rely on the incorporation of cleavable carbon-heteroatom bonds into the backbone by copolymerization, which requires the synthesis of specific monomers and may reduce the thermal stability of the resulting polymers. Therefore, the use of inherent bonds in polymer chains as degradation sites represents a more attractive strategy. 
 In this study, we report base-catalyzed degradation of acrylic polymers via the deprotonation of C–H bonds on the backbone followed by β-scission of adjacent C–C backbones. Using potassium tert-butoxide (KOtBu) as a base, poly(tert-butyl acrylate) (poly(TBA)) with acidic C–H bonds on the backbone was successfully degraded into low-molecular-weight polymers, whereas poly(tert-butyl methacrylate) (poly(TBMA)) without acidic C–H bonds underwent no degradation. This method was extended to methacrylate-acrylate copolymers, where acrylate units serve as initiation sites for degradation. Indeed, TBMA-r-TBA copolymers containing 19% TBA units underwent degradation under optimized conditions, where the molecular weight was reduced from 230,000 to 800, achieving a degradation efficiency of 80%.
 Furthermore, commercially available PMMA pellets composed of methyl methacrylatea (MMA) and methyl acrylate (MA) were similarly decomposed by this method. Mechanochemical-assisted degradation was also investigated using ball-milling without bulk solvents. Additionally, we investigated post-polymerization modification and synthesis of graft copolymers using the backbone C–H bonds as reactive sites.