Enhanced recyclability of methacrylic resins by copolymerization or pendant modification using trityl esters

Abstract

The conversion of pendant groups into poly(methyl methacrylate) (PMMA) to triphenylmethyl (trityl) esters facilitates thermal depolymerization, enabling the recovery of the monomer, methyl methacrylate (MMA). While PMMA offers potential for chemical recycling through depolymerization, its complete degradation necessitates extreme heating conditions exceeding 400 °C. Conversely, a copolymer consisting of MMA (95 mol%) and trityl methacrylate (TMA; 5 mol%), synthesized via free radical copolymerization, undergoes depolymerization at 270 °C, yielding pure MMA with 94.5% efficiency. Additionally, commercially available PMMA sheets and modified acrylic resins incorporating n-butyl acrylate as a comonomer were also successfully depolymerized at 270 °C through pendant conversion to trityl esters, achieving high yields of pure MMA.