The Chemical Recovery of PMMA into Monomer

Polymethyl methacrylate (PMMA), commonly known as plexiglass, is widely used in the areas of aircraft, automobile, construction and transplants, due to its high mechanical strength, good corrosion resistance, and excellent compatibility with human tissue. With the increase in production and usage of PMMA, the vast accumulation of PMMA waste has posed a challenge to the recycling of PMMA waste. However, at present, only less than 10 % of PMMA is recycled each year. The cost-effective chemical recovery of PMMA into monomer with high efficiency has attracted wide attention and has become one of the hot research subjects. The chemical recovery of PMMA into monomer are realized mainly via two approaches, including the pyrolysis of common PMMA at high temperature and the depolymerization of end-functionalized PMMA under mild conditions. The second approach has emerged and achieved significant progresses in the past several years. Herein, we provide a review about the researches of chemical recovery of PMMA into monomer. Firstly, the pyrolysis of general PMMA at high temperature is illustrated by typical research works. Subsequently, the depolymerization of end-functionalized PMMA under mild conditions is highlighted and discussed, as this approach is more in line with the green and sustainable development of polymer chemistry.